I was looking at the EXIF information from a D500 file (I use the Exiftool program to see this information) and saw a mention of “Primary AF point” followed by a “C9”. What’s that? I didn’t have a particular need to understand the entry, so I just moved on. I was recently trying to understand how a D500 uses focus points in controlling lens focus, and found out that none of the image editors use very much (and sometimes none) of the focus point information. Exif data, however, keeps track of what’s going on with the focus points. You can find Nikon-provided information that discusses which focus points will work with which lens; not all focus points work with every lens. This will greatly complicate figuring out the logic behind how the focus algorithms use the focus points. A picture is in order: Nikon D500 focus sensors I found out that Nikon saves focus sensor information in the picture EXIF data much like a chess board. The middle focus sensor, for instance, is called “E9”. You can only select focus sensors that belong to the rows labelled “A, C, E, G, or I”. You can only select focus sensors in the columns labelled “1, 3, 5, 7, 9, 11, 13, 15, or 17”. Note that “cross” sensors are in red, while the less-capable “line” sensors are in black (they all look black in your viewfinder, of course). You can only select the sensors with a little box around them, either red or black (as shown above). You can’t even see the non-selectable sensors in your viewfinder. The auto-focus algorithms that get executed while trying to keep your subject in focus, however, can make use of ALL of the focus sensors (at least with large-aperture lenses). Using something like “Dynamic-Area 25” AF can make use of up to 25 total focus sensors, or two “concentric” boxes of sensors around your selected sensor, which is a mix of both selectable and non-selectable sensors. The D5 includes “Dynamic-Area 9”, but it’s missing on the D500. The D500 in auto-area AF mode, visually appears to ignore any focus sensors except the one that the user selects (called the “Primary AF Point”). Even viewing the photos in an editor with “Show Focus Point” selected will only ever show you the originally-selected focus point, and not what it actually used to focus. The selected focus point shown in Capture NX-D EXIF data for the picture above. As shown above, the EXIF data indicates that I selected the center E9 focus sensor, and it only used that sensor at the time of the exposure. Focus algorithm used more sensors In the above example, several focus points were active at the time of exposure. At the time of this writing, the only way to reverse-engineer what the focus algorithms must be doing requires use of this EXIF information. Best of luck figuring out the focus algorithms. I suppose hammering out 10 fps while wiggling the camera around various targets could get you enough EXIF data to figure out “how they do it”, but you’d better have a lot of time on your hands.

The only camera manufacturers that presently show the public actual measured lens performance data are Leica and Zeiss, and possibly Sigma. The other manufacturers only show “theoretical” performance, typically in the form of an MTF contrast plot. These idealized plots typically are calculated at both 10% and 30% contrast, and separated into meridional and sagittal directions. Another aspect of these theoretical plots: they don't consider the camera sensor being used. Since I typically mount the lens on a camera to use it, I'm kind of interested in the results of the whole combination. This begs the question: do the theoretical MTF plots have any basis in reality? What if you could estimate your car’s pollution output for the DMV instead of them making you get it measured? I thought so. I figured I’d try to answer these questions. As always, trust but verify. I use the MTFMapper program to measure lenses (mounted on cameras). The recent versions of this program let you display (measured) MTF contrast plots, so that they look just like the manufacturer plots. I’m presently using MTFMapper version 0.6.7, which is for 64-bit Windows. The download site for this free software is here. Before you can make lens measurements, you will need to print, mount, and photograph a resolution chart. My chart is about 40” X 60” in size, so that I can take measurements at realistic focus distances. The measuring program can use a few different resolution chart designs, and I am using the newest design. Chart used to make resolution/contrast measurements Another thing: most manufacturers only show their theoretical MTF contrast plots at the widest lens aperture. Most photographers want to know what aperture gives them the best resolution and contrast, plus how much quality difference there is between aperture settings. To answer these MTF questions, I picked on a pair of pretty good lenses: the Nikkor 85mm f/1.4 AF-S and the 105mm AF-S Micro f/2.8 G. These lenses should have decent quality control, plus they're primes, so the theoretical MTF values should have the best chance to match real measurements. I used a Nikon D610 and un-sharpened 14-bit RAW files for the tests. All pictures were taken using a heavy tripod, Live View mode, “mirror-up”, remote release, and contrast-detect focus. I picked the best results from each aperture, out of a minimum of 10 shots at each aperture. I used “cloudy bright” daylight illumination. I used this full-frame camera so that I could get the same range of information as that from the Nikon web site data. Nikkor 85mm f/1.4 AF-S Lens 85mm MTF Contrast Plot from Nikon Web Site (theoretical plot) I grabbed a screen shot from the Nikon site, showing you how the 85mm lens should perform at f/1.4. This plot would assume that their manufacturing plant is capable of flawless lens assembly and their parts exhibit no process variation. Here, the “S” stands for “sagittal”, or the “spoke direction” from the lens center. The “M” stands for “meridional”, or tangential direction. “S10” is for 10% MTF contrast measurements in the sagittal direction, while “S30” is for 30% MTF contrast (represents resolution) measurements in the sagittal direction. 85mm MTF Measured Contrast Plot, f/1.4 (peak MTF50 41.8 lp/mm) The theoretical and actual MTF contrast plots look quite a bit different. Surprisingly, some aspects of the measured plot actually look better than the theoretical. The pink-ish and blue-ish bands around the plot lines show the actual spread of measurements taken; the dark lines are the average of the measurements. Note that the measurements stop at about 18mm (sensor edge), starting from the lens center. The Nikon-supplied plot has measurements out to the corner, or about 22mm. So, how about the other apertures for this lens? What follows are the measurements at other apertures, to give you an idea of how much the lens improves as you stop it down (until diffraction starts to mess up the resolution). 85mm MTF Measured Contrast Plot, f/2 (peak MTF50 45.2 lp/mm) 85mm MTF Measured Contrast Plot, f/2.8 (peak MTF50 55.2 lp/mm) 85mm MTF Measured Contrast Plot, f/4 (peak MTF50 58.6 lp/mm) 85mm MTF Measured Contrast Plot, f/5.6 (peak MTF50 56.9 lp/mm) 85mm MTF Measured Contrast Plot, f/8 (peak MTF50 53.5 lp/mm) 85mm MTF Measured Contrast Plot, f/11 (peak MTF50 45.2 lp/mm) 85mm MTF Measured Contrast Plot, f/16 (peak MTF50 36.8 lp/mm) Notice how the astigmatism vanishes at about f/8 (no more separation between sagittal and meridional measurements). By f/4, even the edge performance is excellent. When you only see the wide-open MTF plot, you don’t get any of this insight. 105mm AF-S Micro f/2.8 G Lens 105mm f/2.8 MTF Contrast Plot from Nikon Web Site (theoretical plot) Above, I show the Nikon web site plot of the 105mm f/2.8 Micro Nikkor (at f/2.8). Now, it’s time to see how this compares to reality. 105mm MTF Measured Contrast Plot, f/2.8 The f/2.8 measured plot differs a bit more from the theoretical plot than the 85mm did. Nothing in the measured plot is as good as Nikon’s claims. I don’t have another 105mm lens to compare to this data, but I’ll bet it would be different from the above data, too. 105mm MTF Measured Contrast Plot, f/4 105mm MTF Measured Contrast Plot, f/5.6 105mm MTF Measured Contrast Plot, f/8 105mm MTF Measured Contrast Plot, f/11 105mm MTF Measured Contrast Plot, f/16 Although the 105mm measurements don’t stack up to the Nikon claims, try to keep in mind that measurements higher than 0.5 (50% contrast) at MTF 30 lp/mm are really good. Again, keep in mind that these plot measurements extend to the frame edge, versus Nikon’s frame corner, when comparing plots. 2-D plot of MTF50 performance, 105mm @ f/2.8 I added an MTF50 plot at f/2.8 to show how much more informative that style of plot is, compared to the mere MTF contrast plot. You get to see the performance all over the surface of the sensor. Conclusion I pretty much expected that the real measured lenses wouldn’t look quite as good as Nikon’s fantasy plots would imply. The measurement plots bear this out. I’ll bet that Canon et al. would show a similar trend. Personally, I still think that the 2-D plot measurements in an MTF50 chart give much better information about lens performance than these MTF contrast plots. The MTFMapper program is capable of providing both kinds of information, so you get to choose. I have attempted to provide all the information that you will need to make similar measurements for yourself. No two lenses are going to be identical, so you need to always keep that fact in mind when looking at lens measurements. #howto

I did a little analysis of the effectiveness of the “electronic front curtain”, or EFC, on the Nikon D500. The EFC is a feature presently available only on Nikon’s high-end cameras, and only available with “Mirror Up” (Mup) mode. When using EFC, the front curtain of the shutter doesn’t move during the exposure, and therefore doesn’t cause any vibrations. EFC camera menu Nikon D500 User Manual EFC explanation Is this feature one of those marketing gimmicks, or is it truly useful? You probably won’t notice much effect until you get to really show shutter speeds and/or really long focal lengths, where vibrations become a severe problem. There are two substantial sources of vibration, even when your camera is mounted on a heavy tripod. The first vibration source is the mirror, which slaps up out of the way of the shutter. Because of this, you need to either stay in Live View mode or wait about 3 seconds before tripping the shutter. The second vibration source is the shutter itself, which is divided into the sudden front shutter curtain motion, followed by the rear curtain motion. When EFC is active in “Mup” mode, the camera will open the front shutter curtain, but not electronically enable the sensor. When you trigger the completion of the photograph, the camera first electronically enables the sensor (and begins the exposure) and then closes the rear shutter curtain to finish the exposure. To test this EFC feature, I set a Sigma 150-600mm lens on 600mm and stopped the lens to f/22 at ISO 100, so that the shutter speed was on 1/30 second. I disable lens vibration reduction during the testing. This is normally a very problematic shutter speed with this long of a lens, but my goal was to force a vibration issue. Note that vibrations are even worse around ½ through 1/15 second. I used a very heavy tripod while testing, but I know that vibrations are still a big problem when using this long of a focal length (900mm effective). I also used a remote shutter release. I shot a resolution target at 16.8 meters, and then used the MTFMapper program to analyze the results. Since the results can vary from shot to shot, I did about 15 photos with and then without EFC active. I got measurements in both the meridional and sagittal directions, since I figured there might be a directional bias to the vibrations. For the non-EFC mode, I ended up with an average MTF50 of 16.6 lp/mm in the sagittal and 21.3 lp/mm in the meridional directions. For the EFC-active mode, I got 23.6 lp/mm in both the sagittal and meridional directions. For the sensor target area I used for measuring the MTF, the sagittal direction was horizontal and meridional was vertical. Subject motion blur was easily visible in the photographs without EFC active; EFC really makes a difference! The percent increase in resolution when activating EFC was (23.6-16.6)/16.6 * 100 or 42% for the sagittal (horizontal) direction, and (23.6-21.3)/21.3 * 100 or 11% in the meridional (vertical) direction. As I stated earlier, the vibrations would have been even worse at slower shutter speeds than this. Using EFC makes a substantial difference in resolution (at slow shutter speeds or high magnifications). There’s really no reason not to enable EFC if your camera has it; note that the D500 does have a shutter speed limit of 1/2000 while using EFC mode. Again, the EFC mode is only available in conjunction with the “Mirror-Up” mode, although you can still decide if you want to use phase-detect focus or switch to Live View and use contrast-detect focus. Either way you use EFC, you still want the mirror up for at least 3 seconds prior to taking the photo. For my camera, EFC mode is disabled by default, which I think is crazy. I’m not sure if other camera models have the same default, but I bet they do. If your camera supports it, then please, please enable EFC right now. Sigma 150-600 at 600mm on D500. Used EFC to rid any vibrations #review

When you want to get to the next level in getting really sharp distant object photos, like the moon, what do you do? Do you really need to get that $16,000-plus 800mm Nikkor? There’s an enemy that keeps you from your sharpness goal, no matter how much you spend on gear. It’s called the atmosphere. So how do you minimize atmospheric “shimmer”? Here’s where software (and science) can come to the rescue. Shooting the moon can be frustrating, for many reasons. After you get your big lens and really stable tripod, you quickly find you’re not done quite yet. You flip up the camera mirror, use a remote release, and even invoke the Electronic Front Curtain shutter. Even at a motion-freezing high shutter speed, you still aren’t getting satisfactory resolution. Evidently, elimination of subject motion and vibration still isn’t enough. Your next step to sharpness is based on image stacking. You might think that you need a motor-driven “equatorial mount” to counteract the Earth’s rotation to successfully combine your multiple shots, but actually you don’t. The software can fix that. The software I’m going to discuss isn’t limited to the moon or the planets. It can also help with any distant terrestrial landscape shots, as long as your subject holds still. The key to sharpness is based on statistics. Most of the time, details of your subject are in the same location, but with a shimmering atmosphere, sometimes they move a bit. If you take several shots of the same subject and look for details that are “usually” present in each of the photos, you can combine these shots into a single sharper picture. Your camera’s focusing system is another sharpness culprit. As soon as your focus system thinks the focus is “good enough”, it stops trying to focus further. As a result, you’ll find that some shots are sharper than others. The software also recognizes this, and is capable of automatically only selecting the “best” shots it locates in a series (a ‘stack’). The program I’m going to describe is called “AutoStakkert”, version 3.0.14 for 64-bit Windows. I’m using it on Windows 10. It’s available on other operating systems. This free program can be located here. The program author is Emil Kraaikamp. There are other astro-stack programs available, of course. Learning their usage nuances can be really time-consuming, so I can in no way claim that this AutoStakert is the best one. I just know that it is capable of doing what I want it to. I converted my raw photos into 16-bit TIF files to use the program, but it accepts a variety of image formats. It doesn’t accept raw formats, though. There are many, many options available with this program, but I’ll describe a couple of recipes that work for me. Keep in mind that the intended users of this program are astronomers, not photographers. I have had best success when using at least 20 pictures in a stack. I’ve seen extreme examples where users have processed more than 10,000 shots in a stack (frames from a video) with this program! The more atmospheric shimmer, the more shots you’ll need to counteract that shimmer. With newer cameras starting to offer 4K video, this is something to keep in mind. Before I forget to mention it, this program can output a ‘sharpened’ photo, but I don’t like the result (totally over-sharpened with haloes). I use the un-sharpened output and post-process it with my favorite photo editor instead. Finished stack result, after applying an un-sharp mask. Using the Program Run the program “AutoStakkert.exe” as an Administrator (right-mouse click on the file to do this). I believe the program author is from the Netherlands, hence the unusual program name. This program doesn’t like raw format, so you’ll need to convert your photos into any of a variety of image formats (I use 16-bit tiff). For my moon shots, I don’t bother to re-center the moon in the frame to counteract the Earth’s rotation. The software takes care of that, when you choose the “Planet (COG)” Image Stabilization option. If you’re shooting distant landscapes, you need to use the “Surface” Image Stabilization option instead, where your subject isn’t moving. If you don’t use a tripod for this, then you might as well stop reading the article at this point. For the other “Image Stabilization” options, I used the “Dynamic Background” but I honestly don’t understand its impact on the results. Leave the defaults in the “Quality Estimator” section. These are “Laplace” delta, “Noise Robust” 4, and “Local”. The “Noise Robust” value should get increased for more noisy or dim subjects and decreased for more quality input photos. For really high quality shots, a Noise Robust value of 2 is suggested. I leave the “Expand” option alone (it will change to “Crop” if you click it). This will leave the output large if you leave it as “Expand”. The “Local” setting uses each alignment point to further assess each frame quality, versus “Global” to use the entirety of each frame. Click the “1) Open” button, and browse to the folder with your (TIF, JPG, etc.) multiple shots to process. Use the “control” or “shift” buttons to select the desired photos to process as a stack. After clicking on “1) Open” and selecting the 16-bit TIF photos, I press the “Play” button to see if the automatic rough alignment was successful. This rough alignment counteracts the rotation of the Earth between the shots, assuming you don’t bother to realign the moon in your viewfinder. The “Play” button starts a slide show running. Image quality grading numbers get displayed next to the “F#” (frame number) on the photo-display dialog upper left side. You can click in the “Frames” progress bar to manually step through the image stack, too. This lets you easily compare how sharp each shot is, relative to each of the other shots. Click “Stop” to halt the slide show. If you have selected “Planet (COG)”, the stack of photos should already be roughly aligned with each other. If you’re trying to stack a landscape and selected the “Surface” radio button instead of “Planet”, you might want to alter the “Image stabilization anchor” location and window size (green X with green rectangle). While in the right-hand dialog showing you one of your photos, you should probably press the “9” key to get the largest “anchor point” area (a green rectangle) The smallest anchor rectangle uses a value of “1”. Smaller number selections will decrease the anchor rectangle selection size. Hold the control button and click on the desired anchor center, which should include a detail that exists in every shot of your (landscape surface) stack. If your rough alignment doesn’t succeed, then unfortunately further stacking operations will likely fail as well. You can delete any shots where the subject moved too far and then try again. Screen shot after photo stack analysis, before clicking “Place AP grid”. Click “2) Analyse”. This will perform an initial quality assessment of the selected pictures, and then decide which are the best ones. It generates a plot of the shot quality as well. The program will place your shots in order of decreasing sharpness. The gray line in the plot is in the same order as the input file stack, and the green line is the sorted order of the frames. Click on the “Frames” button to switch between sorted or original input frame order, and use the slider to switch from frame-to-frame (or else type in the desired shot number). The “Frames” button turns green when this feature is available. If you hover the mouse pointer in the slider area, the tool-tip text will indicate the active sorting order (“The frames are now sorted by quality”). “Frame” slider/input box to view stack images and their quality rating Note the “F# below the slider, such as “F#2 [9/24]”, which indicates the 9th frame of 24 is the ninth sharpest photo, and the second shot (file) in the stack. This example frame is in the “top 34.8% ” of the entire stack, and has a quality rating of “Q 59.9%”. You generally want a photo quality rating of 50% or better in your final stack. There is a zoom slider and horizontal/vertical sliders to magnify and shift the view of the selected photo in the stack. This is an under-appreciated program feature. You might have hundreds of photos, and it would be a terrible chore to manually figure out which ones are the sharpest. This feature automatically finds them and sorts them. You’ll get an error (!#@Anchor) if your shots aren’t aligned well enough for analysis. You’d probably get this error if you did a whole moon shot but selected “Surface” instead of “Planet (COG)”, and the moon was in a different location in each shot. I presume “!#@Anchor” is some form of Dutch swearing. If the Analysis looks good (view the graph for a nice continuous plot showing gradual decrease in image quality of the sorted shots), you’re ready to select the final alignment points. For quality input images, select a “small” alignment point size (AP Size) of 24. For lesser quality images, select a larger number. I have experienced alignment mistakes when using larger alignment point sizes. I’d suggest you use the automatic alignment point creation, which will put many points on your image (see the little blue rectangles with red dots in the image below). Lots of points are needed for quality alignment of the shots in the stack. There’s a manual placement option (“Manual Draw” checkbox), although I haven’t had good success with it. After Analysis, there will be a red rectangle over your displayed photo. If you want to try placing manual alignment points, don’t put any points outside of this rectangle, since some of your shot details go outside of this rectangle. Click “Place AP grid”. This is the automatic way to get the alignment point grid added to your displayed photo. This is fast, easy, and lazy, which I’m all for. It will put a grid of points over the entirety of your subject, but avoids the black background (if you’re shooting moon shots). There’s an “Alignment Points” “Clear” button, if you decide you’re unhappy with your detail selections (and you want to start over). You can try changing the alignment point size, if you wish to experiment with that option. In the left-hand dialog above, I have a value of “30” (green box) for the “Frame percentage to stack” in the section labeled “Stack Options”. This will cause the program to only use the best 30% of the shots in the final processed shot, and it will throw out the worst (most blurred) shots. Use the “Quality Graph” and “Play” results to help you decide on the percentage of sharp shots you want to retain for the final stacking process. The “Normalize Stack” option will enforce a consistent brightness level for each shot, and isn’t typically needed unless you have a non-black sky with your moon. The “Drizzle” option was originally developed for the Hubble telescope. It is intended to take under-sampled data and improve the resolution of the final image. This option doesn’t seem to help my shots any. It will really slow down the stack crunching if you select it. I selected “TIF” for the output format of the final processed shot (under “Stack Options”), which will be placed in this case into a folder next to your input photos, and called “AS_P50”. This folder name indicates it was created by AutoStakkert, and has the results of selecting “50 Percent” of the input shots. I left “Sharpened” un-selected and “Save in Folders” selected. I’m not a fan of the sharpened results from this program, but it can still be a useful evaluation tool, even if it’s not good “art”. You’ll get an extra output file with “_conv” add to its name if you select “Sharpened”. Autostakkert after “Analyze" and “Place AP grid” is done Notice in the screen shot shown above that the program automatically added 1002 alignment points onto the photo after clicking the “Place AP grid”, and added the text “1002 APs”. When I have used less than 300 points, I have noticed occasional alignment errors in the final results. Now, click on “3) Stack”. And wait. Then, wait some more. You’ll get some progress messages with little green check marks and how much time each of them took as they complete. Expect several minutes to elapse before the stacking is complete. The finished output files will be in TIF format if you matched my TIF output format selection. The result pictures include an unsharpened image and also a sharpened image (with “_conv” at the end of the file name). As I mentioned, I don’t like how this program does sharpening, so I post-process the unsharpened stacking result in another photo editor. The finished result (TIF) file has “_lapl4” and “_ap1002” as a part of the file name, because in this example I used the “Laplace” delta, noise robust 4, and created 1002 alignment points. Stacking has completed. Note in the shot above that you can see green checkmarks with timing measurements. This section gets filled in as the program progresses. Finished results (TIF files here) go into the “AS_P50” folder, since 50% percent was selected for the “Frame percentage”. If you had chosen 70 percent, you’d have an “AS_P70” folder instead. You’ll find that the program is smart enough to not only shift your photos for accurate alignment, but it also applies rotation correction! Impressive. Single (sharpened) shot example detail. NOT a stacked photo. The picture above is the best single-shot photo I had to work with, which has been post processed. It is actually missing some subtle details and also has some ‘false’ details, all due to (minor) atmospheric shimmer. It’s pretty good as-is, but can still stand some improvement. The un-cratered “mare” are particularly noisy and contain some misleading ‘false’ detail. I shot this picture with the moon higher in the sky to avoid atmospheric effects. Cold air and higher elevation would have helped, too. Autostakkert final processed shot detail, no sharpening. The shot above shows the result of using the best 50% of my stack of 24 original shots. It still needs post processing (contrast adjust and an unsharp mask). If I had shot many more photos for the stack, the quality would improve even more. Autostakkert final processed shot detail, sharpened Shot detail using Registax wavelet processing If you compare the details between the “single shot” and the finished AutoStakkert stacked (and sharpened) result, you can see several extra details that show up in the stacked picture. Note the smooth surfaces are starting to show subtle shading, which is missing in any of the single shots. The Registax program with layered wavelet sharpening can enhance details slightly better, as well, although it starts to look artificial to me. I added this shot just for fun; I don't think the Registax results look enough like "art" to be useful to me. Autostakkert really does work. If I had shot many more photos, then the results would improve even more. I’m certainly not an expert at using this program, but it’s clear to me that stacking photos can absolutely increase the level of detail that moon (and general landscape) shots contain. It’s almost like getting a better lens than you really have. You could, if you’re inclined to do so, switch to Live View and even shoot a movie (4K or 8K, please) of your subject (converted to AVI) and Autostakkert can use that as input, too. Landscapes If you photograph a distant subject, especially on a warm day, heat shimmer can be severe. Using the “Surface” option (instead of “Planet”), you can dramatically improve subject detail if you use a tripod and take at least a few dozen shots for stacking. Distant landscape “Surface”, with many alignment points The screen shot above shows the selected options for processing a stack of distant (about ½ mile!) landscape shots. Unlike moon shots, you must keep your subject framed exactly the same shot-to-shot for “Surface” processing. If you look carefully, you’ll notice that the auto-alignment grid shows about 27,000 points (!). Just like moon shots, you can “Play” the stack of frames to evaluate sharpness and alignment. Try to stack only the frames that have a quality rating of 50% or better, and rid any frames that don’t align well relative to their neighboring frames. My best single shot in the stack, sharpened, 100% magnification, 600mm The shot above shows more dramatic heat shimmer, due to the extreme distance. This is actually the best of many frames I shot. Fine branch details are obliterated. Stacked result detail, sharpened, 100% magnification Comparing the above pair of detail shots, you’ll notice that the stacked result brings out really fine details that no single shot can deliver. This example used 10 shots of the stack; more would have been better. If there had been more atmospheric shimmer, the differences between single shots and the stacked result would have been more substantial. You'll need to crop the edges of your finished stack result, much like when you do macro focus-stacking. Keep this in mind when framing your landscape shots. Two miles away, 600mm Sharpest single shot detail. LOTS of heat shimmer at 2 miles Stack of sharpest 40% from 106 total shots. HUGE difference! Conclusion If you’ve got the time and motivation to get the very best out of your gear, then give this program a try. You might just find Autostakkert becoming a welcome part of your tool kit. Don’t hold your breath for Photoshop or Lightroom to include features like these. If you’d like to read more explanations of this software, here’s a handy link. The moon photos in this article were made using a Sigma 150-600mm Contemporary at 600mm f/8.0 1/500s ISO 3200 (VR off) using a Nikon D500 with Electronic Front Curtain shutter. I converted the raw shots into 16-bit TIF, with noise reduction, for Autostakkert to use. I’ll bet you didn’t think this lens was as good as it is, did you? Once again, photos and science make a perfect blend for your art. #howto

How can you make one of those cool star field shots, without making the stars turn into streaks? Is there a way to take these pictures without having to buy special hardware? Yes. Star shot made from multiple photos, using CombineZP. There are few things you will need to make good star field pictures. Not surprisingly, the better (and larger) your camera sensor is, the better chance you’ll have to produce quality results. A stable tripod is a must. A lens with a wide aperture will really help. Get a remote release (or a cell phone app) to trigger your shutter. Finally, you’ll need software to align and combine multiple exposures. What you won’t need is a motorized mount that rotates your camera to track the stars; that’s what the software is for. There are many programs that “align” multiple exposures via a simple shift, but the list gets pretty short when you add the constraint to fix rotation. The Earth rotates, causing the stars to appear to move in an arc. I have been using a (free) program called CombineZP that can fix rotation, scale, and shift changes when combining pictures. The CombineZP program was written by Alan Hadley; he’s a really smart guy, but is a little bit challenged by grammar and spelling (to say the least). In case you’re interested, the program name refers to “stacking/combining photos in the ‘Z’ direction” and the “P” is short for “pyramid”. He uses a “pyramid” algorithm for some of his photo stacking operations, which is really great for solving many issues involving overlapping hairs on bug close-ups when doing focus-stacking. Intense stuff. His program’s Help system explains this and many other things. Alan’s program can do much more than bug shot stacks, as I’ll show you. Here's a link to his free program. The CombineZP program works with Windows10 and many earlier versions of Windows; I use it in Windows 10 x64, although it’s a 32-bit program. I almost forgot to mention that you also need a really dark sky. City lights and the moon will generally ruin your results. The higher altitude and less humidity you can get, the better. The kind of photography I’m talking about here doesn’t work for night landscapes (with a horizon), because you can’t mix a fixed horizon with moving stars. This article is about pure star shots. When I photograph stars, I will typically use my Nikon D610, which has a really, really good full-frame (FX) sensor. My go-to lens is my Tokina 11-16mm f/2.8 (DX), even though it’s not supposed to work on a full-frame camera. It works just fine at 16mm, although I typically crop the edges a bit to rid some vignetting and frame-edge astigmatism/coma. If I owned something as snazzy as the Nikkor 14-24 f/2.8, then I’d definitely use that instead. To get my star photographs, I will typically set my camera on manual exposure, ISO 3200 (or less), f/2.8, and a shutter speed of 10 seconds for 16mm shots. Shutter speeds longer than 10 seconds at 16mm will result in star streaks. This kind of photography requires manual focus on infinity (it’s smart to pre-focus while it’s still daylight). These shots will be under-exposed, but the CombineZP (and some other post-processing software) will brighten things up in the final picture. If you choose a longer focal length lens, they you’ll need to use shorter shutter speeds to avoid getting streaks instead of points of star light. Take a test shot and zoom in on it to view how much streaking you see. I’d recommend you take a minimum of 4 shots to combine. The more shots you have, the better results you can get. Don’t wait too long between shots. Manual method using CombineZP for stacking shots: Convert your Raw star shots into 8-bit Tiff, LZW compression, with an image editor of your choice. CombineZP won’t accept Raw format or 16-bit. Start CombineZP.exe Click “Enable Menu” icon to see the menu system. Click File | New Select the TIFF photos (as-shot order), then wait until each shot is loaded into the stack. Select Stack | Size and Alignment | Auto (Shift + Rotate + Scale), OK. (This will align and replace each shot in the stack with the aligned shots.) Your screen will probably look black after the alignment is done, but that’s normal. Select Stack | Enhanced Average to Out Lowlight Gain (0=none) enter a value between 0 and 50. Press OK. Highlight Attenuation (0-1000, 0=none) enter 0. Press OK. Brighten (1000=stay same) enter 2000 (for 1 stop brighten, 3000 for 2 stops, etc.), Press OK. The “Enhanced Average” step lets you tune the exposure adjustment of the photos, and then combines them (and reduces noise via averaging the shots). When processing is done, mouse-drag a rectangle around what you want saved. In this case, it’s as if you’re using a crop tool. Click File | Save Rectangle As | myStarShot.png (You can choose an output format from jpg, tif, bmp (24 or 32 bit), gif, png.) Now, your “stacked” shot is ready for final adjustment in your favorite photo editor. You will probably want to do additional noise-reduction, Levels and Curves adjustment, white balance adjustment, and apply an un-sharp mask. Create a Macro to Automate Star Stacks If you’re a little more ambitious, you can create a macro to do your star stacks, once you settle in on a recipe you like. Alan explains how to make macros for his program, but here’s a Cliff’s Notes version if you want to try it out. The CombineZP program has several collections of macros, saved in files that have the .CZM extension. Inside these collections, you can have up to 10 macros. Macro names that look like “_Macro4”, “_Macro5” etc. are place-holder (inactive) macros without commands in them (unless you put some there). Since the default macro set has 10 active entries, you’ll need to either make your own macro set or alter an existing macro set. Find an appropriate “macro set” (.czm files) that has an available macro via Macro | Load Macro Set (I will choose “Enhancer.czm”) You’ll want to replace a place-holder name in the set with your new macro: Macro | Edit | Macros. Click on “_Macro 3” to alter it (if you used Enhancer.czm). Note that your new macro name cannot begin with an underscore character, or it won’t be runnable via a user click. The Macro Editor, before any changes. Rename an unused macro (starts with “_Macro”) to a name without an underscore. Here, we’ll call the new macro “Star Stack”. Add steps, along with any parameters it needs, by selecting a “Command” in the drop-drown list. For the first command, we want to align the already-loaded stack of photos: Align the stack Click “Update/Paste” to add the Align command to the macro. This command will replace each original star shot in the stack of loaded images with aligned ones (not touching your original .tif files). You now have a new “stack” of images to perform further operations upon. Next, we want to get the “average” of each shot in the stack, to rid noise and atmospheric interference effects. We also want to enhance the light in each shot while combining it with the others. “Enhanced Average to Out” command with (3) parameters Click the “Update/Paste” button to save the averaging command. The “Enhanced Average to Out” command expects to operate on a stack of images (with any number of images in the stack). It will then place the results into the “Out” location, which is visible on the screen. Click the “Save Macro” button, once all of the steps are added. Click the “Ok/Update” to exit the Macro Editor. The finished Star Stack macro The new macro stack Click on the “X” to close the “Edit Macro” dialog. For use in the future, you will want to save this macro set into a new file. Click Macro | Edit | Save Macro Set As | StarStacker.czm Try out your new macro: File | Empty Stack (to clear out everything) File | *New (select the original .TIF files of the star shots) Macro | Star Stack (It should now run and do both the alignment and averaging) Do the usual “save rectangle as” to save your results. After you’re done running the new macro, you may want to restore the system with the default macro set (for focus-stacking). Click “Macro | Restore Standard Macros” The program now looks like it did when you first started running it. You can now do regular focus-stacking operations. To get back to your new star macro, do this: Macro | Load Macro Set | StarStacker.czm This particular example isn’t very sophisticated, but it shows you the way into the world of CombineZP automation. There are a great many more macro sets to explore that are provided with the program. You can use the help system to research the commands in the sample macros to learn more. Now, get out there and shoot the stars. #howto

Back in the olden days, before computers were generally available, Nikon was making the nicest lenses you could get. How do these antiques stack up to modern lenses? I thought I’d take a look. The Nikkor 300mm f/4.5 was my very first “good” telephoto. This thing even pre-dates “auto indexing”, although later I got a kit and converted it to AI (AI, or auto-indexing, was invented in 1977). It does have Nikon’s NIC (Nikon Integrated Coating) multi-coating. Auto-focus hadn’t been invented yet (Nikon started in that game in 1986). Internal-focusing lenses were about a year away. Nikon’s “ED” (extra-low dispersion) glass hadn’t quite been introduced yet (it got introduced in the next generation 300mm lens). We’re talking 1975. To even the playing field a bit, I have picked my Sigma Contemporary 150-600mm lens for a comparison, which I’ll zoom to 300mm. This Sigma is definitely not the best lens out there, but I think its representative of what is widely available today (and it’s actually cheaper in today’s dollars than the Nikkor was in 1975). Back in the day, no self-respecting photographer would stoop to use a zoom lens; they were complete crap then. This 300mm Nikkor lens was produced from 1975-1977. The aperture is 6-bladed, which is not very nice for “sunstars” or lights at night. It has a rotating, locking, non-removable lens collar that is excellent for balancing on a tripod. It has a wonderful permanent telescoping lens shade, which I sorely miss on today’s lenses. This lens looks, feels, and acts like its brand-new; I expect it to last well beyond my own lifetime. I can’t sufficiently describe how excellent this lens is for manual focusing. It has precisely the right dampening, rotation range, and smoothness. The ‘feel’ of the focusing hasn’t changed any whatsoever over the life of the lens. Nikon built this metal lens to the highest possible mechanical standards. Don’t get me wrong, though. Manual-focus on a long lens is generally a real pain. Ever since Nikon abandoned the “split-screen” focusing screens, precision and fast manual focus is a thing of the past. You can still get accurate manual focus on a long lens, but it pretty much requires the use of a tripod or really stopping down the aperture. It’s possible to buy focus screen replacements, but I heard Katzeye is out of business, and other makers cause really dark viewfinders. I configure my cameras with the “Non-CPU lens” menu setting, and shoot with aperture-priority (or manual) mode, so auto-exposure isn’t any different from modern lenses (except you turn the aperture ring instead of a wheel). If you haven’t used an AI lens before, note that you still get to focus and shoot with a wide-open aperture. Your camera does need to have an aperture-coupling lever, however (I heard they abandoned this on the D7500). Even though such things are totally correctable in post-processing anyway, I thought I’d mention that vignetting, distortion, and chromatic aberration are minimal on this lens. Oh, I forgot to mention that it has a 72mm filter thread size. Also, the lens only focuses down to 13 feet. Nikkor 300mm f/4.5 AI-converted on Nikon D610 with lens shade extended Resolution Testing I haven’t ever seen any resolution analysis of this lens, so that’s what I’m going to concentrate on in this article. I used my Nikon D610 (24 MP, 5.95 micron pixels). I’m only showing the Sigma results at f/5.6 (where the Sigma resolution is at its worst). The MTFMapper software I used for resolution analysis produces charts showing “smoothed” measurements. It’s possible to get at individual resolution measurements, however, in both the meridional and sagittal directions. I did my testing at 10 meters, which is a realistic shooting distance for 300 mm. Beware of measurements where they shoot a lens of this focal length at maybe 4 or 5 meters. Sigma at 300mm f/5.6 (worst aperture) resolution chart detail, D610 Nikkor 300mm f/8.0 (best aperture) resolution chart detail, D610 Peak Resolution Results The Sigma, at 300mm f/5.6, had peak resolution measurements of 48.5 MTF50 lp/mm, or 2329 lines per picture height. Again, this is at the Sigma’s worst aperture! The Nikkor had the following peak resolution measurements: f/4.5 MTF50 lp/mm = 25.1 (meridional and sagittal) f/5.6 MTF50 lp/mm = 25.1 (meridional and sagittal) f/8.0 MTF50 lp/mm = 40.2 (sagittal), 38.5 (meridional) f/11.0 MTF50 lp/mm = 36.8 (sagittal) f/16.0 MTF50 lp/mm = 33.5 (sagittal) The Sigma totally smokes the Nikkor when comparing the same aperture measurements. The Nikkor at f/8.0 and beyond, though, is quite respectable. Since I’m generally against trying to give a single number that represents resolution, the following section shows you the overall lens results. Full-sensor Resolution Measurements First, I’ll show the Sigma at 300mm and f/5.6 and then we'll take a look at the Nikkor. Sigma 150-600 MTF50 lp/mm resolution at 300mm and f/5.6 Sigma 150-600 MTF10/MTF30 contrast at 300mm and f/5.6 Now, here’s the Nikkor 300mm results. I stopped measuring after f/16.0, although the lens stops down to f/22 (and diffraction is really kicking in to spoil the resolution). Nikkor 300mm MTF50 lp/mm (smoothed) resolution at f/4.5 Definitely not up to present-day resolution standards. Nikkor 300mm MTF10/MTF30 contrast at f/4.5 Nikkor 300mm MTF50 lp/mm (smoothed) resolution at f/5.6 Nikkor 300mm MTF10/MTF30 contrast at f/5.6 Nikkor 300mm MTF50 lp/mm (smoothed) resolution at f/8.0 Nikkor 300mm MTF10/MTF30 contrast at f/8.0 Nikkor 300mm MTF50 lp/mm (smoothed) resolution at f/11.0 Nikkor 300mm MTF10/MTF30 contrast at f/11.0 Nikkor 300mm MTF50 lp/mm (smoothed) resolution at f/16.0 Nikkor 300mm MTF10/MTF30 contrast at f/16.0 Sample picture Full picture sample Crop from near the picture center Conclusion In the right hands, this Nikkor 300mm is capable of making beautiful photographs. The level of effort, skill, and patience required for an old manual-focus telephoto lens isn’t for everyone. And forget about birds in flight. And avoid placing your subject in the frame corners. I suppose I’m just sentimental, but I have no plans for ever letting go of mine. I think of it as a real collector’s item. #review

When you do close-up photography, there’s a whole new set of rules to get quality results. I’m talking really close up. Believe it or not, your lens will perform better when it’s mounted in reverse. It will also magnify the image more. When you get this close, you’re also going to have to learn about focus-stacking. I have an article on my close-up hardware that is located here. An article on stacking software is located here. A related program I also use is called “CombineZP”, which has similar stacking features, plus a few more. There are many programs that feature focus stacking; I try to stick with recommending stuff that is free. Some lenses that aren’t meant for macro photography can become quite useful when they’re mounted in reverse. My favorite bellows close-up lens has 52 mm filter threads, which fits my “BR-2” lens reverse ring. For my lenses with larger filter threads, I use “step-down” rings to step from the larger thread diameter down to the 52 mm thread size. I haven’t seen any vignetting by doing this, so don’t worry about this being a problem. I’ll be talking about Nikon lenses here. All of their newer lenses have the “G” designation, which means they have the “feature” of no aperture ring. Believe me, you’re going to need their older macro lenses if you want into the larger-than-life game. If you reverse and/or mount a lens on a bellows, you’re going to lose electronic connections with your camera and therefore electronic aperture control. With the Nikon auto-focus lenses that have an aperture ring (mostly the “D” lenses) you can unlock their minimum-aperture setting and have full use of their aperture. For even older manual-focus lenses, their aperture rings “just work” as-is. You’ll always want to stop down the lens (typically to f/8) for best quality. At high magnifications, the depth of field becomes too shallow to be useful, which is where the focus-stacking software comes into play. Most of my macro shots are stacks of typically 20 to 80 shots. I move the lens on the bellows rack by about 0.2 to 0.5 mm per shot, until I’ve photographed my subject from front to back in slices. I also use a ring light mounted on the (now front-facing) rear of the lens, which I slip over my BR-3 ring that’s mounted to the lens rear. A ring light vastly simplifies lighting and also helps with focus. There are flash and continuous-light ring lights; I prefer the continuous light, but vibrations can be a challenge. Stacking photos obviously means that it’s limited to static subjects, such as deceased bugs. Please don’t kill anything just to photograph it; very uncool. 60 mm Micro Nikkor AF-D reverse-mounted. A bee is checking it out. The shot above shows the 60 mm f/2.8 Micro-Nikkor AF-D lens with step-down rings to attach its 62 mm filter threads to the 52 mm BR-2 lens reverse ring. The LED ring light shown slips over the BR-3 ring mounted on the rear of the lens. I use the PB-4 bellows. You can find modern equivalents of this gear on the web, or maybe locate the original equipment on E-bay. I normally use my 60 mm Micro-Nikkor mounted directly on my camera and stick with magnifications of life-sized or less, plus electronic flash. I just wanted to point out that the AF-D lenses have fully functional apertures when reverse-mounted on a bellows, but you need to get step-down rings to do this combination. Nikkor 105 mm f/2.5 Reverse-mounted, including lens shade The photo above shows my 105 mm f/2.5 Nikkor (pre-AI!) reverse-mounted on the PB-4 bellows. This lens allows a magnification range from 0.28X through 1.6X on the bellows. For lower magnifications, the working distance is as large as 16 inches (and therefore allows use of the lens hood). At maximum magnification, the working distance is reduced to about 115 mm. I keep the lens parked at its infinity setting. This lens isn’t as optically good as the modern 105 mm f/2.8 G Micro Nikkor, but at least it has a working aperture ring on the bellows. When you want to try really, really magnified subjects, you can try mounting a short-focal-length lens. I have tried my 20 mm lens, but I don’t like the image quality. My favorite lens on the PB-4 bellows is my old 55 mm f/3.5 Micro-Nikkor. I have many close-up shots in my gallery page taken with it. I can get magnifications anywhere from 1.68X through 4.3X when it’s reverse-mounted. The quality is simply sublime. It has a working distance at a near-constant value of 75 mm at any magnification setting, which works fine with my LED ring light. This is a bit too close for most live bugs, however, since they’re too skittish for this. The LED light also cuts into the working distance range, so I only use it for static subjects. 105 mm f/2.5 Nikkor (pre-AI) reversed 1.5X focus stack While it isn’t optically stunning for macro, the quality of this 105 mm is very good when reversed. 55 mm f/3.5 Micro Nikkor reversed 4.2X It can be fun to try going way beyond life-size with a bellows. Did you know that a light bulb filament has coils within coils? You’d never know it, if you weren’t able to see beyond life-sized. The blue coils are made of tungsten; they can withstand the extreme temperatures inside a light bulb. Beware that vibrations can get outrageous at these high magnifications. I use the “mirror-up” or live-view mode when using continuous lighting. If your camera supports it, then you should also enable electronic-front-curtain shutter mode. I always use either a wired or wireless remote shutter release. Electronic flash will of course freeze the subject motion. I find extreme close-up photography very rewarding, yet challenging. You get to explore things that are otherwise invisible. If you aren't the patient type, then this venue isn't for you. This is yet another example of how science (focus-stacking software and modern computers) enables a whole new area of art. It's a great time to be alive. #howto

To get the best quality panoramas, there’s more to consider than just how well your pictures are stitched together. You want to stick with RAW format for as many of your editing steps as possible. If you use Lightroom 6 or newer, and you install the (still free) Nik HDR Efex Pro 2 plug-in, you can make maximum-quality panoramas and also have a large tool set for creativity. Update 8-8-2020 The plug-ins from Nik aren't free anymore. You can get the latest plug-ins from DXO. When shooting the pictures, try to keep about a 50% overlap between shots. Don’t forget to try vertical format shooting for a slightly taller panorama. Lightroom is also capable of multi-row panorama stitching. It’s best to shoot your pictures with a single manual exposure setting, so that the frames will match up better. If you’re careful, you can even get by without using a tripod (I use viewfinder grid lines as alignment guides). HDR panorama using Lightroom and HDR Efex Pro 2 Select the RAW photos to stitch into your panorama Before beginning panorama creation, you may wish to perform any “lens correction” steps on the individual shots, since Lightroom can still recognize the lens data at this point. The first panorama creation step, after you import your pictures into Lightroom, is to select the range of pictures to stitch together (click the first, then use the Shift key and select the last shot in the range). Merge your shots into a panorama Next, click Photo | Photo Merge | Panorama… You’ll get a dialog box that lets you decide between Spherical, Clyndrical, or Perspective projection. Click each selection to decide which projection type looks best for your panorama. Select the “Auto Crop” to clean up the frame edges. Click on “Merge” when you’re satisfied with the projection type. Select your new panorama After the panorama is stitched, you’ll need to select it. Note the panorama is saved in DNG raw format, which lets you have maximum flexibility for further editing enhancements. “DNG” is the Adobe “digital negative” format that is very close to “raw”. The light range and color range (bit depth) is maintained, allowing for maximum highlight recovery, shadow recovery, and “tone mapping”. I tend to lump HDR and tone mapping together, but many photographers consider single-shot manipulations to be “tone mapping”, while multiple overlapping shots at different exposures are required to be considered HDR (high dynamic range). Now would be a good time to do the usual sharpening, noise reduction, color balancing, highlight and shadow manipulations, etc. Because the panorama is in DNG format, you have the maximum flexibility for editing at this stage. For many panoramas, you might be ready to simply export at this point into the finished file format, such as jpeg. Or maybe you’re ready to try the Nik HDR Efex Pro 2 plug-in. Assuming you want to try HDR and you’ve installed the Nik plug-in collection from Google, you’ll next need to select File | Export with Preset | HDR Efex Pro 2. Show a little patience here; it will take a while before Nik is ready. As an aside, Google no longer supports the Nik plug-in collection. As of this writing, though, it’s still available for free download from their web site here. I use the Nik plug-ins in Photoshop, Lightroom, and Zoner Pro. Try out some HDR selections in HDR Efex Pro 2 Use Zoom and Navigator to inspect HDR shot details HDR Efex Pro 2 output file format selection Try out the various canned options and fine-tune controls in HDR Efex Pro 2. Don’t forget to use the Zoom/Navigator controls to inspect details. Most people either love or hate HDR. I fall into the love category. When you’re happy with the HDR effect you want, click on Save to return to Lightroom. HDR Efex Pro 2 won’t allow you to save your picture in raw format, so you should have finished your other editing steps in Lightroom before the conversion to HDR. Only jpg or tiff formats are available for output. #howto

Here’s a very specialized kind of a post-processing to simulate a lens with an impossibly thin depth of focus, yet a very wide angle. The guy who is credited with developing the technique is Ryan Brenzier, who uses it mainly for wedding portraits. This kind of photo is intended to isolate the main subject, and makes it look as if you used something like a 20 mm f/0.2 lens wide open. This look is achieved by making a multi-row panorama while using a fast lens at a wide aperture. The effect might even remind you of something that a “LensBaby” might produce. This technique is used for when you want a wide shot, yet you want to isolate the subject. I’ll show you the results of using an 85 mm lens at f/1.4. You’re supposed to use a tripod to enable good control for aligning each overlapped shot (overlapped by both row and column) in the whole grid of photos. On purpose, I tried to see what would happen if I instead hand-held the camera (a sort of worst-case scenario). As with any panorama, it’s best to overlap the shots by 30 to 50 percent. A multi-row panorama requires the shots not just overlap side-to-side, but also above and below. You don’t have to take the shots in any particular sequence; you can start with your main subject and expand out from there, too. You might want to count your shots for each row, so that you get more predictable results when they get stitched together. Try to shoot all of the pictures containing your main subject before it (or they) can move. The shots that are out of focus aren’t as critical as far as minor movement is concerned. If your panorama shooting is going to be time-consuming, then do your people subjects a favor and get their shots in the sequence done first. I used Lightroom 6.14 to create my multi-row panoramas. You use the same menu options for creating a multi-row panorama that you’d use for a single row; Lightroom just figures out what to do. You can, of course use any software that handles multi-row panorama stitching. A word to the wise: re-sample your input photos to have lower resolution. When you create a multi-row panorama, the finished picture can be huge and take a really, really long time to stitch. You’ll thank me for this tip. As with any panorama, it’s best to stick with both manual exposure and manual focus. Don’t change either while shooting the collection of pictures you’re going to use. To physically create the panorama, start by selecting the range of pictures and then click on: Photo | Photo Merge | Panorama… If Lightroom is unable to stitch the pictures, you might try one of the other “projection” options before giving up. I have found that “spherical” is the most forgiving. You might find that one projection option gives you very different picture height-to-width proportions compared to the others. All it will cost you is some time to explore various projection effects. It’s often the case that there might be a little re-touching required, ala the “healing brush”, in the stitched panorama. This will be especially true if subjects are moving a little during the shooting operation. I'm getting quite fond of using Lightroom for stitching, because I usually have very little cleanup work to do. You might also need to perform a little “distortion removal”, if you are close to objects or your panoramas are very wide. Avoid backgrounds that have straight lines, if you want to save yourself a little work. I feel compelled to mention that extreme perspective distortion might be exactly the effect you want; some rules beg to be broken. Lightroom panorama stitching via the ‘Develop’ module I found that Lightroom cropped off several of my hand-held shots, primarily from having ragged row widths. I would have had much better success if I had used a tripod to control shot-to-shot alignment. Not too surprising. The shot above is comprised from roughly 3 rows of 5 shots per row, taken using vertical format. I'm glad I tried this hand-held experiment to convince myself that I don't have to avoid attempting this technique, just because I'm somewhere without access to a tripod. Razor-thin depth of focus over a wide angle Conclusion This type of photographic technique probably won’t find itself being useful on a daily basis, but it might be just the ticket for a special portrait. It’s just one more tool that you should be aware of. If you want your shots to stand out from the crowd, give the Brenzier Method a try. #howto

Here’s a real power trip: make your own worlds! You’ll need a photo editor that lets you map your photo into ‘polar coordinates’. I use Photoshop to get this fun effect, because it has a distortion filter to project the picture pixels into polar coordinates, which is called “mapping”. The ‘planet’ effect won’t work for all subjects; you need to preplan what you shoot to help yourself out. I will typically start with shots that I stitch into a panorama, although the effect can work with a single photograph, too. Try to find a subject that has similar characteristics on both the left and right sides, such as the same height of sky and foreground. You will be doing yourself a favor if you use manual exposure for stitched photos, so the light will balance best between the opposite sides of the final merged photo. A really crowded planet Let’s begin with a panorama that has roughly matching left and right sides. While I shot the original sequence, I was trying to visualize how well the opposite sides of the view would wrap around and touch each other. Start with a balanced shot I was careful to avoid allowing the main subject matter to extend to the top of the frame, because it will cause an ugly effect that would be difficult to blend after mapping the shot into polar coordinates. I arranged for both the sky and the water in the shot above to be reasonably easy to blend together, making it a good candidate for the planet effect. The left and right sides of the panorama have about the same height of sky and water, and their brightness is similar, too. Make the image into a square Before you can convert into polar coordinates, the picture needs to be in a square format, so you need to make the image width match the image height. Make sure the “Constrain Proportions” isn’t selected. Turn the image upside-down You will also need to rotate the square image 180 degrees prior to conversion into polar coordinates. If you skipped this step, you would end up with a “tunnel” effect instead of a “planet” effect. You should try leaving the shot un-rotated sometime to see what happens; there may be subjects where a tunnel effect looks good. Map the upside-down photo into polar coordinates Now you can convert your picture into polar coordinates (from rectangular coordinates). Click Filter | Distort | Polar Coordinates. Make sure the image scale is small enough to preview the conversion effect (click the little “minus” button). Smooth the seams and picture frame edges Now, you’ll need to use the “healing brush” to get the seams and edges of the frame to blend well. There are always some edge spokes you need to tame. You might use the clone stamp here, too. This is where the real effort takes place. It can take a fair amount of finesse to blend the seams to get the shot to look good. Pre-planning your original photos will help minimize how much time and trouble there is to blend the final picture. Rotate 180 degrees to get right-side-up again Now rotate the picture to get it back to the original orientation. You can of course rotate any amount and then crop the shot to your desired proportions, too. Truth be told, I did a little extra 'healing brush' work after what's shown above using Zoner Pro. I like its more sophisticated healing brush tool a bit more than the one in Photoshop. I don't think any single photo editor is the best at everything. There you have it! Your very own planet. Go easy on this technique; a few planet shots are fun, but turning everything into a planet is a bit much. #howto

The newer high-end Nikons, including the D500, let you assign different focus modes to different buttons. Why would you want such a thing? It’s all about fast reactions. Many camera models and camera generations have of course allowed you to set the “focus mode selector” switch to auto-focus and then press the “AF-mode” button and spin the main command dial to AF-C for continuous auto-focus. Similarly, many models have the “AF-ON” button, or buttons that can be assigned this focus-on-demand feature. That’s only the beginning. It’s silly to ever select AF-S mode instead of AF-C mode, since all you have to do is stop pressing the AF-ON button (while in AF-C mode) to stop focusing. A much more subtle focus requirement is to do something like ignore objects near your desired subject, or to ignore a branch in front of your subject. As soon as you figure out how to select the desired number of focus points or how to set near-subject focus priority, something changes to spoil your shot. Now, you need to start all over again, because your camera insists on focusing on a near branch, or maybe you can’t keep that single focus point (single-point AF area mode) on your erratically-moving target. The point is, the focus requirements never seem to stop changing and you just can’t keep up. You’re tired of missing those shots. What to do? The newer high-end Nikons let you at least triple your chances of getting the shot. Now, you can assign multiple buttons with auto-focus, and each button can have a totally different focus mode assignment. The Nikon D500, for instance, will let you assign the “Pv”, “Fn1”, “Sub-selector” (joy stick), “AF-ON”, and your battery grip “AF-ON” buttons with different focus modes on each one of them! On my D500, I presently have the following button assignments: AF-ON = D25, thumb control, for ‘general-purpose’ focus. Pv = Group Area, middle finger control, for near-subject priority. Sub-selector = Single-point, thumb control, for precision focus. Grip AF-ON = “=AF-ON” copies whatever the camera AF-ON has. I don’t assign the “Fn1” button for focus, because I think its awkward to press it while my index finger is on the shutter release. More acrobatic users may not have this same issue. For me, I only want to use either my thumb or my middle finger to activate focus. Unfortunately, the Sub-selector button is squirrelly, and I have to use the focus-selector lock lever to prevent the joy-stick from moving to different focus points instead of acting like an AF-ON button. To assign these buttons on the D500, you go to the “Custom Settings” (pencil) menu, “f Controls”, and then “Custom Control Assignment”. For each of the desired buttons, you select “AF-area mode + AF-ON”. Each button sub-menu under this option lets you select “Single-Point”, “D-a AF 25, or D72, or D153”, “Group-Area AF”, or “Auto-Area AF”. Auto-focus options for button assignment Note that not every auto-focus option is available to these button assignments (e.g. 3-D tracking isn’t there). Because this is Nikon, different camera models offer a different set of AF assignment options. The Nikon D5, for instance, has the “D9” available, but the D500 starts at “D25”. When you press your assigned button, the viewfinder will instantly change to show you the corresponding active focus-point pattern. This way, you get visual confirmation that you are using the focus mode that you intended. Single-Point AF viewfinder view (center point selected) 25-Point Dynamic Area AF viewfinder view Group-Area AF viewfinder view The point I want to make here is that your choices aren’t set in stone. You can experiment with different modes assigned to different buttons until you feel comfortable with them. Don’t go overboard with changing the assignments all the time, however; it will totally mess up your muscle-memory. Once you get used to using different buttons to get different focus modes, you’ll wonder how you ever got by without them. You can now react nearly instantly to changing conditions and get those shots that you used to miss. This is one of my absolute favorite things about using my D500. #howto

I really love shooting with high-speed lenses, like my Nikkor 85 mm f/1.4 AF-S. In some ways, these lenses are like finicky race horses; they aren’t always as well-behaved as you’d like. The Nikkor 85 mm f/1.4 is legendary for its beautiful out-of-focus rendering (bokeh), combined with being sharp at the focus plane. This beautiful bokeh is achieved by a lens design that avoids the use of any aspherical lens elements. The price paid for this bokeh is an effect called “focus shift”, caused by spherical aberration. The outer portions of the lens will focus the rays of light a little differently from the inner portions. If you stop the lens aperture down, those outer light rays are cut off, and don’t contribute to the image. The spherical aberration effect results in the best-focus plane to be located at what’s called the “circle of least confusion”. As you stop down the lens, the “circle of least confusion” shifts, until it stops shifting at typically f/4 or so. If Nikon engineers had used aspherical lens elements in their design, they could have virtually eliminated any spherical aberration. This would have given the lens even higher resolution at large lens apertures (with virtually no improvements at smaller apertures). All designs involve trade-offs, though. Lenses with aspherical lens elements translate into worse bokeh, all else being equal. You start to notice that out-of-focus blobs look like sliced onions, with concentric rings of light-dark patterns. Lights that are visible in the background at night really emphasize this effect. The outer edges of light blobs should gradually melt into the background; they shouldn’t show a ring of light around the edge of the blob. This aspherical tendency is only a generalization, however. As computer modeling gets better, lens bokeh is getting better with lenses having aspherical elements. Sigma, for instance, has a single aspherical element in their 85 mm f/1.4 Art lens; its bokeh can’t compete with the Nikkor, in my opinion, but I can’t say it has ugly bokeh, either. Circle of least confusion with spherical aberration The diagram above lets you visualize what happens as you change the lens aperture. The plane of best focus is located at the “circle of least confusion”, where the light rays get focused into the narrowest bundle. This light bundle always has a non-zero diameter, but gets best at around f/4.0 on the Nikkor 85 mm f/1.4 AF-S. I got the diagram above (I added the labels and arrows) from this site. Many thanks to this organization for making a great graphic depiction of the “circle of least confusion”. The circle of least confusion travels from left-to-right in the diagram as you stop the lens down. With a small aperture, the light rays near the outer portions of the lens get cut off, and the remaining rays (which are consistently focused at a point) now predominate. At a small-enough aperture, focus shift stops. If you keep stopping the lens down, then diffraction starts to take over. The light ray bundle starts to expand again, although it no longer shifts. Resolution starts to degrade in proportion to the expansion of the light bundle. Note that spherical aberration is a result of lens design, and doesn’t correspond to manufacturing variation. You won’t find a lens copy that eliminates spherical aberration, so you can stop looking for one. Nikkor 85mm f/1.4 AF-S lens elements The picture above is from the official Nikon web site, showing the lens elements, which are pure “spherical” shapes. Spherical lens elements have a constant radius on each surface, which makes them much easier to grind than an aspherical surface. The constant radius translates into smooth out-of-focus backgrounds. When I do focus fine-tuning on my camera, I have to note the aperture that corresponds to each fine-tune value (from wide-open until about f/4.0). Unless you shoot using contrast-detect (live view), you’ll need to change the fine-tune value to match the aperture, or else your pictures will be slightly out of focus. Phase-detect auto-focus uses the lens at its widest aperture, which is why you get the focus error. Contrast-detect uses the shooting aperture, which is why you don’t get any focus error in that mode. Some sample calibrations for my cameras look like this: D7000 f/1.4 = tune +1, f/4.0 = tune -4 D7100 f/1.4 = tune +12, f/4.0 = tune +8 D500 f/1.4 = tune +3, f/4.0 = tune 0 D610 f/1.4 = tune +7, f/4.0 = tune +2 The focus shift consistently moves away from the camera as the aperture closes, so the “+” focus-tune needs to decrease to compensate as the aperture closes. As a result, the fine-tune value needs to be decreased as the lens is stopped down. After f/4.0, the focus shift is no longer noticeable. Focus calibration chart, f/1.4, left side rotated further away Focus chart, f/4.0 showing focus shifts further to the left (away from camera) You can see in the focus charts above how the plane of focus shifted to the left (away from the camera) when stopping down. To fix this, the focus fine-tune would need to change from [+7 at f/1.4] to [+2 at f/4.0] for this camera (to shift focus toward the camera). The focus chart was rotated to 45 degrees, with its left side further away from the camera. I used the MTF Mapper program to analyze the photos of the focus chart. It makes it really easy to locate where the focus plane is. It also lets me know how much sharper the lens is when I stop down the aperture! In case you thought of this, I tried to press the “depth of field preview” (Pv) button while I focused. The theory here is that the lens would be stopped down for the phase detect, to eliminate focus error. Unfortunately, the camera refuses to focus while the “Pv” button is pressed. Oh, well. I try to pay as much attention to the backgrounds as I give to the main subject in photographs. Bokeh is really, really important to me. That’s why I love my 85 mm lens so much that I’m willing to put up with its annoying focus shift. If only this lens had vibration reduction… #howto