I have found the Topaz Photo Studio  editor to be amazing at intelligent object removal. Artificially intelligent, that is. Neighbors and No Neighbors     It’s possible to use Topaz Photo Studio  alone (drag photos to its desktop icon), but I find it preferable to send the photo to Photo Studio  from within my photo editor (normally Capture One ). I always use raw format for the best quality. Launch Photo Studio  from the photo editor   In Capture One, you just right-mouse-click in the photo to bring up the ‘Edit With’ menu. Launch Photo Studio from within the editor, and then convert the shot into DNG format.   It’s still a raw format, which will retain image quality.  Don't do any photo edits before doing this step, since those edits will be discarded. Wait until after processing in Photo Studio  to do any more photo editing. Convert the photo into DNG format To remove objects in  Photo Studio , select a new filter   Note that Topaz has already applied the “RAW denoise” filter. It will always do this step automatically when you send it a DNG (raw) photo. Pick the ‘Remove’ filter Goal: remove the car and the sign in the photo above Draw a mask over an object   Use the ‘removal’ brush to draw over an object. If you have several objects to remove, it’s best to do them one-at-a-time. Click the ‘Remove’ button after drawing over an object. There’s a “Size” slider to alter the brush size. If you make a mistake drawing the mask, you can click the “Add/remove” ‘+’ or ‘-‘ buttons to add or erase the mask.   You can move the zoomed image view around the screen if you hold down the ‘space’ bar. If you prefer, you can change the image magnification to “Fit” the screen using the drop-down list that shows “100%” by default, at the bottom of the window. After clicking ‘Remove’, the car is gone!   Note in the shot above just how intelligently the car was removed. The AI figured out how to re-create the ends of the stairs, for instance. Add some more masks to rid small distracting objects After clicking ‘Remove’ again, the distracting sign is gone   When all of the unwanted objects are removed, click the “Done” button. You are then free to select more filters, such as another “Sharpen” filter. The vertical slider shows the ‘Remove’ filter effect   The vertical white slider can be used to review the ‘before’ and ‘after’ of the filter effects. Just slide it left/right across the photo.   When you’re finished with Photo Studio , just click the “Export to Capture One” (or whatever photo editor you are using). The DNG-format photo will be automatically added to your photo editor catalog, and you’ll be returned to your photo editor to do more editing.   This sophisticated level of object removal is only possible using artificial intelligence. Your photo editor ‘healing brush’ and ‘clone brush’ are no match for this.   For full disclosure, I have had issues with both Topaz Photo AI and Photo Studio  occasionally crashing my computer. I tolerate that irritation, because these programs are so good as sharpening, noise removal, and object removal. My computer exceeds all of the Topaz specifications for CPU memory, GPU memory, disk space, etcetera, but I still have problems. I have tried every version through 4.0.4, but they all cause problems.   I have found that Topaz Photo AI  and Photo Studio  essentially interchangeable programs.

I have found that a single photo editor is rarely sufficient for getting the best results. For starscapes, I use a combination of Topaz Photo Studio and Capture One23. Yosemite Valley night sky   To properly capture the light of the Milky Way, you need a long exposure, but not too long. Let me explain. In the shot above, I wanted the longest exposure I could make that didn’t show star trails. For this shot, I used my Sigma 14-24mm f/2.8 Art lens at 14mm, f/2.8 and 25 seconds at ISO 3200. I always shoot in raw format.   For this 14mm field of view, exposures longer than 25 seconds start to show the star trails, due to the Earth’s rotation. The Topaz Photo Studio (and Topaz Photo AI 4.0.4 ) has a sharpening feature to rid subject motion. I thought that this feature was the ticket to taking really long starscape exposures, but I thought wrong.   Stars in the night sky move in an arc, and not a straight line. The Topaz programmers that train their AI models give it examples of subjects moving in a straight trajectory. When their program is given photos of a subject moving in an arc, it doesn’t recognize that as being ‘motion’, so no motion blur correction is applied. That sucks.   I hope that at some future date the Topaz people will train their AI motion blur correction with star trails. The following discussion shows you how to process star shots such that motion blur correction would  be used, if their AI model gets smarter.   As an aside, I also tried the ON1 Photo RAW  editor, including its “Tack Sharp AI” to rid motion blur, but it didn’t rid star motion blur, either. 14mm f/2.8 at 25 seconds, ISO 3200 with no editing   The shot above shows what the stars and landscape look like before editing. I used my Nikon Z9 in ‘manual’ exposure mode. I use a wired remote release and a sturdy tripod. Launch  Topaz Photo Studio  from Capture One   Before I do any editing in Capture One , I send the picture to Topaz Photo Studio . Inside the Capture One editor, I right-mouse-click the star shot to get the “Edit With” dialog and select the “Process with Topaz Photo (Studio)”. My Topaz Photo AI  works just as well.   Any edits to the raw-format photo will be ignored when you send the picture to Topaz Photo Studio , so don’t bother doing any editing yet. Wait until the photo gets processed in Topaz for more editing back in the Capture One  editor later. The raw (NEF) shot will get converted into another raw format (DNG). Always stick with raw-format for editing, to maintain maximum quality. Topaz Photo Studio   When Topaz Photo Studio  gets launched, it will automatically select the RAW denoise filter when it is given a raw-format photo. For the ISO 3200 shots, the ‘RAW Strong’ denoise strength is preferred. Topaz claims that the RAW denoise filter also automatially removes 'hot' pixels.   It’s possible to add another denoise filter, but usually the ‘RAW denoise’ filter will be sufficient. Click the ‘100%’ to alter the view magnification   Change the default 100% magnified view, because the selection mask is virtually guaranteed to be WRONG. Select “Fit” to see the whole shot Click “Select a filter”   To add another filter, click the “Select a filter”. Pick the ‘Sharpen’ filter next Pick the “Motion blur” filter and the “Sky” mask   As I previously mentioned, the above “motion blur” sharpening filter selection is largely wishful thinking. In the future, I hope the Topaz programmers will get some better functionality behind this. It still does sharpen the stars, however. The AI-generated sky selection mask: pathetic   I’m guessing that the “sky” selection mask is so terrible because it’s a dark nighttime shot. The AI-generated ‘daytime’ selection masks are generally pretty good. Click on the “Edit selection” to modify the Sky mask Clean up the Sky mask   As shown above, adjust the mask-selection brush diameter to both add/erase the red ‘sky’ selection mask. When painting the mask is done, click the “Done” button. In theory, the software would then eliminate the star motion trails and leave sharp points of light. The landscape is left untouched by this motion blur mask. Add another filter (for the landscape) Add a ‘Sharpen’ filter for the Landscape   Add a sharpening filter for the landscape. With low illumination levels, you probably won’t see too much effect on the landscape. Just like the sky, the landscape AI selection mask will probably be really poor. Adjust the mask-selection brush Brush over the entire landscape, then click ‘Done’ It’s possible to remove airplane/satellite tracks…   There is a ‘Remove’ filter option to rid unwanted satellite and airplane light tracks from the sky, but I personally don’t like the results. I save these edits for the Capture One  editor, where I use the healing brush to do this operation. Click “Export to Capture One”   Click the “Export to Capture One” to return to the Capture One editor, where this DNG-format sharpened/noiseless photo will get automatically added to the Capture One  catalog.   Now, you’re going to edit the DNG version of the starscape. Edit the DNG version in Capture One   You can see the edits that I performed in the Capture One  editor above, as shown by the red arrows.  I used the healing brush to get rid of the unwanted satellite track.   I left the landscape quite dark, with just a hint of details. You can, of course, lighten the landscape to your liking (mostly increasing the ‘Shadow’ slider).   The sky color temperature (Kelvin) should be adjusted to taste; most people prefer a cooler color temperature. Star trails close-up with a 60-second exposure   What’s shown above is a star shot after  motion-blur removal with Topaz Photo Studio . The trails were unfortunately virtually unaffected by the motion-blur filter. This is why I keep my exposures shorter, and I don’t depend upon software to fix star trails after the fact. Starscape with editor adjustments to lighten shadows more   I really like how Topaz Photo Studio and Topaz Photo AI  rid image noise and also sharpen details. They just don’t work for fixing star trails (yet).

There are actually physical limits on how sharp your photos can be. Physics itself demands these limits, no matter how much you’re willing to spend on a premium lens. Your camera sensor places additional limits on just how sharp a photograph can be.   Lens Limits   Something called the “Airy Disc”, named after George Airy (1801-1892), places absolute limits on a lens’ sharpness. A lens can only focus a point of light within certain bounds, related to the color of the light being focused. Airy disc in 3 dimensions, courtesy Google AI   Light is actually a 3-D thing. A point of light focused onto a camera sensor looks more like a splash of water. Light waves of different colors have different lengths, where blue light is shorter than red light. Green light is somewhere in the middle.   When a lens aperture is stopped down, the size of this Airy disc starts growing in diameter. The Airy disc diameter is only  a function of the aperture f-number and the color (frequency) of light. When apertures are idealized as being a perfect circle, the Airy disc diameter, measured in microns, can be estimated to be 1.34 times the aperture f-number for green light (549nm or 0.549um). For blue light, for instance, the Airy disc diameter is smaller. Green light can be between 500nm and 600nm, but 549 was chosen here.   The Airy disc formula is:   Airy_disc_dia = (2.44 X frequency_um X F_stop)   For the above,     frequency_um = 0.549 Airy disc sizes with green light   In the table above, I’ve shown how big the Airy disc gets at different lens apertures. I also mention a camera sensor with pixels that are 4.35 microns across, such as my Nikon Z9 and Z8.   This shows that a lens that has absolutely perfect optics can only focus a point of light within limits, depending upon the lens aperture and the light color (frequency).     Camera Sensor Limits For you to notice the image getting fuzzy, the size of this Airy disc has to grow until it covers more than a single pixel on your camera sensor. A rule of thumb is to start getting concerned about diffraction when the Airy disc grows to be two pixels across or more. For making prints, this rule can be loosened up considerably.   For camera sensors that have anti-alias filters (to help rid any Moire effects) the images are even fuzzier.   The sharpness limits for the camera sensor are summarized by what’s called the Nyquist Limit  and the Kell Factor .   According to Edmund Optics , the absolute limiting resolution of a sensor is the Nyquist Limit which is half of the sampling frequency (pixels/mm). For the Nikon Z9/Z8, the sensor is 8280 X 5520 pixels. The dimensions are 35.9mm X 23.9mm. The Nyquist limit is (8280/35.9)/2 pixels per millimeter (231/2 pix/mm) horizontal or (5520/23.9)/2 pixels/mm vertical, or again (231/2) pix/mm.    The Nyquist limit of (231/2) lp/mm is then 115.5 lp/mm.    The typical actual frequency response includes what’s called the “Kell Factor” named after Raymond Kell, which is conservatively set to 0.7.  This value helps compensate for the physical space between the light-sensitive portions of the pixels, and to avoid patterns similar to the moire effect. This means the practical actual sensor frequency response limit is now (115.5 X 0.7) or 80.85 lp/mm.   Given this information, any measured lens resolution above 80.85 lp/mm for this camera sensor is unreliable.     My Best Lens   For me personally, my best lens is the Nikkor 500mm f/5.6 PF. I tested it on my Nikon Z8 camera, where I found that I needed to do minor focus fine-tuning to optimize its focus. Several focus test results for my 500mm f/5.6 PF lens   The resolution results from the data plotted above got an average MTF50 resolution of 77.1. The peak reading was 84.1, with a standard deviation of 5.3.   Using the MTF50 average of 77.1 lp/mm, this lens is quite near the calculated sensor limit of 80.85 lp/mm. As an aside, these measurements are better than I have been able to obtain using my Nikon Z9, although I haven’t been able to figure out why that is (even with focus fine-tune).   If Nikon had made this lens any sharper, you’d never be able to detect it without buying a camera with smaller pixels in the sensor. The absolute sharpest possible lenses would also have the widest aperture, and not suprisingly they'd be super heavy with all of that glass.

Nikon’s Z8 version 3.0 firmware adds the capability to zoom the viewfinder to 400%. I wanted to see if this level of zooming during manual focus could allow even more accurate focus than autofocus.   The most accurate focus that I have tried on my Z8 so far is the “Pinpoint” AF, which is only available in AF-S mode. It’s only a hair better than using 3D focus in AF-C mode, so I rarely bother with Pinpoint focus. For routine day-to-day focus, I much prefer AF-C with 3D focus and the practicality of AF-C over AF-S. What follows is a study comparing those 3 kinds of focus modes.   Manual focus practicality and ease of use heavily depends upon the focus ring range of rotation. Lenses with 180 degrees and less of total focus ring rotation range are quite difficult to get critical focus, especially while hand-held.   I used my Sigma 70-200 f/2.8 Sport lens in these tests, zoomed to 120mm at f/2.8.  Its focus ring rotation range is about 135 degrees, which is fairly typical of AF lenses. The 400% viewfinder zoom was quite challenging to focus; I kept overshooting the best focus slightly. This is a good problem to have, however; the viewfinder made it easy to see how focus changed with even the slightest focus ring rotation.   To get the best analysis of focus accuracy, I will use the MTFMapper program. It is far more picky than human vision to discern what’s in focus, via its resolution measurements of a test chart. The Fn2 button assigned 400% zoom Full LCD display 400% display zoom is pretty extreme     I set up the camera on a tripod and used a wired remote for all of the photographs to rid vibrations. I took 10 shots each with AF-S/Pinpoint, AF-C/3D, and manual focus with 400% zoom. I de-focused between each test shot to guarantee a full re-focus each time.   I assigned the viewfinder zoom feature in the Custom Controls menu to the Fn2 button. The new addition to the version 3.0 firmware is to go beyond 200% all the way to 400% zoom. While using autofocus, the zoom is automatically centered on the current focus point position.   One of the AF-S, Pinpoint shots of my resolution chart got messed up when I accidentally tugged on the wired remote. Since the resulting resolution measurement on that shot was terrible, I omitted that shot from the data that follows. Sample resolution measurement using AF-S, Pinpoint AF-S, Pinpoint test chart with overlaid measurements Sample resolution measurement using AF-C, 3D AF-C, 3D test chart with overlaid measurements Resolution measurement using manual focus, 400% zoom Manual focus, 400% zoom chart with overlaid measurements Each resolution measurement Resolution data plot   If you don’t notice much resolution change from one type of focus method to another, neither do I. That’s a good thing. It means that manually focusing can get just as good of results as autofocus, as long as you use the viewfinder zoom to analyze critical focus.   I decided long ago that focus-peaking wasn’t quite accurate enough for critical manual focus; you could only get approximate focus. By combining focus peaking and the zoom feature, you can be confident that your manual-focus shots will be sharp. Focus peaking is still an excellent way to rapidly get ‘close’ to correct focus.   With the Fn2 button assigned to the viewfinder zoom, it’s simple and fast to press it and toggle between the ‘normal’ and ‘zoomed’ view. Sometimes, 400% seemed a bit extreme when compared to 200% zoom. Since it’s programmable, it’s great to be able to change your mind whenever you want.

Nikkor 500mm f/5.6 PF and Sigma TC-1401 tele-converter     I never did much questioning about using a tele-converter when I needed more optical reach. Since I tend to live by “trust but verify”, it seemed prudent to actually compare using a tele-converter to simple image cropping.   Besides magnifying the image, a 1.4X tele-converter will also slow the lens by one stop. This one-stop light loss also  introduces extra image diffraction, which complicates matters a bit.   If you choose to crop an image instead of using a tele-converter, you don’t get the chance to alter the depth of focus for the same subject distance. For example, 500mm f/5.6 at 10 meters depth of focus is 0.13m. On the other hand, 700mm f/8.0 at 10 meters depth of focus is 0.09m. Most people would rather have the smaller depth of focus that the tele-converter would provide.   I have the Sigma TC-1401 1.4X tele-converter. It works just fine on my Nikkor lenses, even though Sigma and Nikon both tell me not to do it.  There are of course lenses that aren’t compatible with any tele-converter, and I’m not discussing those lenses.   I tested a few lenses to see how much the tele-converter messes up the resolution, and found that the tele-converter was well worth the slight drop in resolution. I particularly like this tele-converter mounted on my Sigma 70-200 f/2.8 Sport lens. My mirrorless Nikons have no trouble with the loss of one f-stop of light, either. Before I got mirrorless Nikons, I never used this combination of the 500mm f/5.6 PF Nikkor and the Sigma TC-1401. The f/8 aperture resulted in unreliable focus with my DSLRs. Even my Nikon D850 and D500 cameras would often fail to focus in deep shade. My mirrorless cameras focus just fine with the tele-converter on this lens, in just about any light.   I use the free MTFMapper   program  to test lens resolution and other lens optical characteristics. This program gives me very comprehensive information on how a lens performs optically.   When I tested my 500mm lens with the 1.4X tele-converter on my Nikon Z9, I got a surprise. The following was what I found. 500mm f/5.6 PF Nikkor MTF50 resolution   The resolution plots shown above give me the overall lens resolution throughout the frame, in both the meridional and sagittal directions. The peak lens MTF50 resolution at f/5.6 was found to be 61.5 lp/mm, which is the same as 2940 lines per picture height on my Nikon Z9 camera. MTF Contrast plot at 500mm f/5.6   The most common plot of lens performance, as shown above, is an MTF contrast plot. I have included measurements at 50 lp/mm, which most manufacturers omit. Test chart edge measurement details at 500mm f/5.6   Overall, this lens is really good, even wide-open. The resolution is consistently high across the whole field of view, at least in the sagittal (wheel spoke) direction.   I mounted the 1.4X tele-converter on the lens and then repeated the resolution testing. This is the equivalent of a 700mm f/8 lens. Nikkor 500mm with TC-1401: 700mm f/8 MTF50 resolution   The EXIF data when using the Sigma 1.4X teleconverter doesn’t notice that the teleconverter is attached, so it still indicates 500mm f/5.6.  In reality, this is 700mm f/8.   The peak lens MTF50 resolution at f/8 was found to be 43.9 lp/mm, which is the same as 2098 lines per picture height on my Nikon Z9 camera. MTF Contrast plot at 700mm f/8 Test chart edge measurement details at 700mm f/8     The lens resolution at 500mm is 2940 lines/ph, compared to 2098 at 700mm, or 61.5 lp/mm versus 43.9 lp/mm.   So, how do we know if using the tele-converter is “worth it”?   Cropping changes the “picture height” portion of the equation, because there are effectively fewer millimeters of image height. The 1.4X tele-converter retains 71.43% of the image width and height, or 1/1.4.   Cropped resolution = (original_resolution) * (1/TC_magnification)   TC_magnification = 1.4X   Cropped resolution = 2940 * (1/1.4) = 2100 lines/ph   Lens MTF50 resolution with  tele-converter = 2098 lines/ph This resolution is the combination of the tele-converter effects and also the 1-stop-dimmer diffraction effects.   Here, it’s better to NOT use a teleconverter! You don’t gain any resolution at the effective 700mm.   If the cropped resolution is equal to or greater than the tele-converter mounted onto the lens, then you s houldn’t  use a tele-converter. Especially when you consider that you’re losing at least a stop of light, it just isn’t worth it.   If the reduced depth of focus is important to you, however, you might opt for using the tele-converter anyway.   If you notice the autofocus getting too slow, then you may opt for cropping the 500mm setup instead.   I tried these same tests on my Nikon Z8 camera, and the 500mm with the 1.4X tele-converter performed better  than on my Z9. In that case, using the tele-converter is worth it.   Not every lens responds the same way to a tele-converter. Take nothing for granted.

A step-by-step tutorial on how to create a resolution chart and use it to measure your lens resolution. Find out how sharp your lens is!

If you own a Nikon Z6, Z7, Z8, Z9, or Zf-series camera, there’s an often-overlooked feature you might just love. It’s possible to assign the focus magnification to the Fn1, Fn2, and movie record buttons, amongst others.   With the high-resolution EVF, you can then instantly see your subject at 50%, 100%, 200%, and even 400% (on some models) magnification. When you want to return to the normal view, all you need to do is press the same assigned button again.   This feature is mainly intended to ensure critical focus on your subject, especially when performing manual focus. I now find myself using this feature most often just to see distant subjects really, really close up.   While it’s true that you can hit the ‘+’ and ‘-‘ buttons to creep in on high magnification, I find it preferable to instantly jump between high/normal magnification. I also find it simpler to locate my assigned function button instead of the ‘+/-‘ buttons on the camera back while looking through the EVF. As a bonus, the +/- buttons are also smart enough to center on the focus point/subject box. 200% zoom on rear camera monitor, Nikon Z9 and 500mm lens   The samples I’ll show in this article are shot viewing the Nikon Z9 rear monitor, which has far less resolution than the EVF does. The same zoom feature works for both the EVF and the monitor. The Z8 and Z9, for instance, have a 3.68 million-dot EVF but only a 2 million-dot monitor. I didn’t have any easy way to photograph the EVF, so I shot the rear monitor instead. Just keep in mind that your viewfinder will show a much more detailed image than these monitor shots.   If you own a Z8 or Z9, there’s an added bonus that the viewfinder operates in real-time, without any time lag at all.   I used my Nikkor 500mm f/5.6 PF lens in these sample photographs. Prepare to assign a button to the screen Zoom on/off feature Selecting the Fn2 button for assignment on the Z8 Select the Zoom feature Select a zoom magnification (some models go up to 400%)       The zoom view is automatically centered where the focus point is located when performing auto-focus, or else where the subject is found if it’s recognized. It’s possible on the Z8 to have the zoom centered on where the subject appears (instead of the focus point), when using subject recognition with manual  focus. Similar to a telescope, you’ll probably need your camera on a tripod with telephoto lenses if you use a high zoom magnification. Many times, the 200% and 400% zoom options are simply too powerful.   The multi-selector arrows are intelligent and know to move in small amounts when you’re zoomed in. This allows you to gradually move around the image and manually track small subject movements.   If you prefer, you can also move around your subject by swiping your finger on the monitor while zoomed in. When I tried this on my Z8 camera, at least, it would even re-focus on the new center of the monitor. This was unexpected and impressive. Be aware, however, that this mode will snap a photo, too. If you don’t want this, then disable or select “Playback only” in the wrench (Setup) menu “Touch controls”. Nikon Z9 rear monitor using 500mm lens   In the shot above, the subject was automatically grabbed and surrounded by a grey box. The focus point, in this case, won’t be used for centering the zoom; the grey box will be used instead. Rear monitor after pressing the Fn2 button for 200% zoom Nikon Z9 rear monitor using 500mm lens 200% zoom rear monitor (warm air shimmer blurs the image a bit)     You may want to change the zoom factor that you use, depending upon which lens is mounted on your camera. Just go back to the Custom Controls menu to alter the magnification.   If you haven’t tried this feature yet, you’re in for a treat. You won’t have any excuses for not verifying a sharp photo. You won’t have to wait until you review the shot to know if you nailed the focus.

The July 1, 2025 version 3.0 firmware for the Nikon Z8 lets you combine focus-shift shooting with pixel-shift shooting. This combination allows your deep-focus photos to also have extreme resolution (about 180 MP) with less noise.   To do anything with this new feature, you will also need to use NX Studio  and a focus-stacking program, such as Helicon Focus . You’ll also probably need to use Adobe DNG Converter , since most editors don’t understand the NEFX image format for the pixel-shifted photos. Focus-stacked, pixel-shifted shot   Before you consider shooting with this new feature, I need to provide you with a little reality check. You need to have a big memory card, lots of disk space, and a very fast computer. I did an experiment with fairly reasonable shooting options to get some idea about what we’re dealing with.   I chose to shoot using “High efficiency” raw format, which is much smaller than compressed raw. I made a 30-shot stack, which yields a reasonable depth of focus for the stacked photos. I selected “16” shots for pixel-shifting to get high resolution and decent noise reduction.   The High efficiency raw shots take about 19.2MB per photo. Shooting a 30-shot focus stack of 16-shot pixel shifts yields a total of 480 photographs. The camera memory card needs over 9.2GB for this many photos.   My liquid-cooled HP Omen computer uses the AMD Ryzen 9 5900X 12-core 3.7GHz processor. It has 64GB of RAM. The GPU is the Nvidia GeForce RTX3080 with 8704 cores. My Z8 ‘ i ’ menu includes focus-shift shooting New firmware 3.0 ‘Focus shift shooting’ menu   Note that the Z8 V3.0 firmware for Focus shift shooting includes extra capabilities, including exposure-locking and the option to reset the focus position back to where you started.   Shown above, I have decided to shoot 30 sets of photos at each focus distance, with a step width of 5. Next, I will configure the number of pixel-shifted shots at each of these 30 focus distances. I will configure 16 pixel-shifted shots per each of the 30 focus distances. Look in ‘Options’ of Focus shift shooting for pixel-shifting     To set up pixel-shift shooting while performing focus-shift shooting, go to the ‘ Options ’ menu option inside ‘ Focus shift shooting ’. Select the ‘Pixel shift shooting’ option Go to the ‘Number of shots’ option Select the desired pixel-shifted shots, with 4,8,16, or 32 Pixel-shifting while focus-stacking is now configured     Now that the shooting is fully configured, it’s now possible to start the shooting of (30 * 16) = 480 photos. Merge the shots in Nikon’s free NX studio   Use the “Pixel shift merge” option inside NX Studio  to convert each set of 16 pixel-shifted raw shots into an ‘NEFX’ merged photo. Click ‘All pictures’ to combine everything at once   NX Studio  is smart enough to recognize each batch of pixel-shifted shots, so that you can get all 30 sets of 16-shot pixel shifts at one time. The raw NEF shots will be combined into an NEFX pixel-shifted shot.   After waiting for 24 minutes on my computer, I had a set of 30 NEFX photos, with each photo being 914MB in size. The combination of each NEF shot and each NEFX shot totals 36GB! I don’t believe that NX Studio  takes advantage of the GPU, so this step is quite tedious.   Next, the merged pixel-shifted shots need to get converted into the ‘DNG’ raw format for my Helicon Focus  focus-stacking program. It doesn’t understand the ‘NEFX’ format, but it does know the DNG raw format. I use the free Adobe DNG Converter  program for the conversion from NEFX into DNG. Fortunately, this DNG converter is really fast.   The 30 converted DNG files consume 13.6GB of disk space. For those keeping track, the (36GB + 13.6GB) now totals 49.6GB  for all of the NEF, NEFX, and DNG files! That’s (480 + 30 + 30) = 540 files, and I still  don’t have my stacked photograph to edit. I used Helicon Focus  to stack the 30 DNG-format pixel-shifted merged shots   The Helicon Focus  program is smart to enough to make maximum use of my GPU, and is able to stack each of the 453MB DNG-format shots in just 3 minutes. Note the photo on the left side, which demonstrates the depth of focus of a single shot in the stack.   All totaled, I have consumed 564GB of disk space to finally get my stacked DNG-format result, which I can then edit in my photo editor. I used the Capture One  editor along with my Topaz DeNoise  program (which of course means generating yet another photo, in TIFF format) to get a proper photograph. I have to convert the TIFF photo into a JPEG photo to publish on the web. Whew. If you're willing to put up with all of this blood, sweat, and tears, the end result is a photo with incredible resolution, low noise, and deep focus.

The July 1, 2025 Nikon Z8 firmware upgrade to version 3.0 has a very nice feature addition for manual focus. This feature works for both AF lenses using manual focus and totally-manual focus lenses with no ‘smarts’. It really helps you nail focus by letting you zoom in exactly where you want it to. Eye detection using manual focus   The feature called “MF subject detection area”, in the “Photo Shooting” menu, is half of this new focus-assist option. It lets you choose between 3 area types, “All”, “Wide(L)”, and “Wide(S)”, in addition to the default “Off”.   If your subject is outside of the selected “detection area”, you of course won’t get any subject detection. Subject detection area in manual focus 3 subject detection area choices       The other half of this new feature is the “AF/MF subject detection options”, which is right above the “MF subject detection area” option. It used to only work for auto-focus mode, and has the same options for subjects that it previously had. Manual-focus subject detect now available Select the same subject types that auto-focus has     To actually take advantage of the new subject detection area feature, you also need to use the display zooming feature. When you zoom, it automatically zooms with the detected subject centered in the zoom. Speaking of the display zoom, the new 3.0 firmware now allows you to zoom all the way to 400%, instead of the previous maximum of 200%.   I have assigned the “Fn2” function button to have “Zoom on/off” via the “Custom Controls (shooting)” menu. This allows me to toggle the zoom feature on and off with the press of a button, where I’m already centered on the detected subject (usually the near eye of a person or animal). Get ready to assign a button for zooming Selecting the “Fn2” button for zooming Select Zoom on/off toggle for the Fn2 button Select the zoom magnification, up to 400%     The display looks a bit different, depending upon using a fully manual “dumb” lens or a “smart” lens that you want to manually focus. In either case, subject detection still works as long as you are looking at a suitable subject. A “dumb” manual-focus lens programmed for birds     Note in the shot above that the subject detection found the eye. I used focus-peaking to get a rough idea of where to focus. By the way, when I switched from “bird” to “auto” subject detection, the camera would no longer automatically detect the eye. The subject-detection box is white with this “dumb” lens. Press the “Fn2” button to zoom in   By pressing the assigned “Fn2” button, the viewfinder zoomed in, centered on the 'subject-detect box' over the eye, which was automatically placed by the subject detection. I could now work on adjusting manual focus with a lot more confidence.   After adjusting focus, I just press the “Fn2” button again to see the whole frame. This ability to toggle between a magnified and full view of the frame is really golden, especially when it zooms in exactly where the subject detection box is presently located. A “smart” auto-focus lens using the manual-focus ring     When switching to a smart lens (the Nikkor 28-400 Z lens), the display shows the little grey box where the subject’s eye was detected. The red square shows where I had placed the focus point (which is ignored during manual focus). When I press the “Fn2” button to zoom, it centers the display on the grey box and not  the red focus point. The magnified view zooms in exactly where I want     I still  need to have the “Focus peaking display” active, via the “Custom Settings Menu”. I almost always use the “low” sensitivity, which has the value “1”. This is also the “accurate” sensitivity, versus being somewhere in the vicinity of “in focus” with the “high sensitivity” setting.   Focus peaking disappears when you activate the zoom feature, but at least it will allow you to quickly get to the “pretty close” focus zone.   Unfortunately, the focus point still  never turns color from red to green when you manually achieve focus on the subject under the focus point, which is why focus-peaking should always be active.   Summary   The new subject-detection feature is invaluable for critical manual focus. I wish that there was an “in-focus” indicator that was tied to the subject-detect grey/white box as well, but I’m just being a bit ungrateful. Thank you, Nikon, for this new Version 3.0 firmware feature that you didn't have to give us.

It’s difficult to appreciate just how complex modern zoom lenses are. In this article, I’ll try to show some of the amazing technology and complexity that is built into a typical Nikon zoom lens.   I disassembled the Nikkor 55-300mm f/4.5-5.6G AF-S ED VR DX lens into its basic components. This lens has very complex glass elements inside it, and these elements have to shift in a very complicated way relative to each other while zooming.   There are also some electrical aspects to zooming, which are there to provide feedback (saved into the photograph EXIF data) about the focal length. Nikkor 55-300 mounted on Nikon Z9 with FTZ-II adapter The 55-300 lens elements, courtesy of Nikon   This lens has 17 different lens elements. For zooming purposes, the elements are housed into 4 different groups. You might think that just the front group of glass moves during zooming, but that’s not even close to what actually happens. The front of the lens, which ‘telescopes’ during zooming   The shot above shows the front section of the lens, which moves away from the camera when zooming to longer focal lengths. 4 main groups of optics   Note that the optics group that’s second from the right above. This group also contains the lens aperture (on its left end) and the vibration-control mechanism (on its right end).   The (left side above) front group has 3 lens elements. The next group behind the front group also has 3 lens elements. The group that includes the VR control and aperture has 7 elements, and the group nearest the lens mount has 4 elements.   As you’ll see, these 4 groups are moved separately from each other during zooming, which alters the relative spacing of each group. The lens front spiral guides   Just inside of the lens front is a cylinder with spiral ridges and grooves. The interior portion of the lens front has cams that move along these grooves when twisting the zoom ring. The first 3 lens elements, which include the exterior front lens element, move together when the lens front moves along these grooves.   The spiral ridges keep the lens front stable and wobble-free, while maintaining a minimum of friction with only a small area of actual surface contact. These ridges are coated in a high-quality grease to further reduce friction.   Note the second group of optics is visible at the top of this module. This optics group movement is controlled separately from the front-most optics group. The lens front spiral guides viewed from behind Lens front spiral guides separated from ‘middle’ zoom sleeve.   Shown above, the front spiral guide sleeve has been turned upside-down and separated from the ‘middle’ zoom sleeve. The middle zoom sleeve shows both a white roller-cam and a black roller-cam in its grooves. These white and black cams move along very complicated grooves, which adjust two separate sets of optical groups.   The shapes of these grooves accommodate the very complex relationship between the optics groups that control the focal length. The spacing between these optics changes at a very un-even pace while zooming. There are actually 3 separate sets of grooves with their independent path shapes. The grooves are machined in triplicate around the sleeve, to provide an even load distribution.       The optics shown on the left-hand side above represent the third optical group. This group is mounted inside the vibration-control module. This same group has the aperture blades mounted at the opposite end. Cams at right-hand side of the grooves   At the zoom position shown above, the optics are at their deepest inside the inner zoom sleeve. The inner zoom sleeve has straight slots in it, and the optics are sitting at the bottom of these slots. This would be the 300mm zoom position. Cams at left-hand side of the grooves   At the zoom position shown above, the optics are at their farthest outside of the inner zoom sleeve, at the top of the inner sleeve’s straight slots. This would be the 55mm zoom position. Side view at mid-zoom position   Note in the shot above that the cams move along straight grooves on the inner sleeve. This moves the optics while keeping them parallel to the camera sensor. The sleeves are coated in grease to reduce the sliding friction. Side view, near the 55mm zoom position Zoom sleeves with optics removed Middle zoom sleeve by itself   Imagine the insane mathematics that goes into these path shapes. Modern optics design is incredibly complicated. Inner zoom sleeve with its straight slots   The cams slide in these slots to push the optics groups forward and backward to adjust the focal length. It’s all coated in messy grease. Who would have expected so much grease inside a lens? Zoom sleeves with optics and cams     Focus SWM stepping motor for autofocus   Just below the SWM motor, with its green teeth, is the gear train that the motor spins to adjust focus. This little motor is only 12 millimeters in diameter, yet it has the power and accuracy to obtain and track focus with very little battery drain. Only the 7-element group of optics gets moved to obtain focus. The front and rear optics groups don't move during focusing. This is what they mean by an "internal focusing" lens.     Focal Length Detection Electrical conductors for focal length detection   The picture above shows 5 rows of gold conductors. 4 of these rows are segmented into an uneven pattern. These rows are the mechanism for how to determine the “Focal Length” setting, which gets saved into the photograph EXIF data.   When you zoom, little conductive ‘fingers’ get dragged along these rows. Depending upon the zoom setting, some fingers will complete a circuit, and some fingers won’t. The 5th (bottom) row is just an electrical ground to complete the circuit.   The vertical positioning of the gaps in the top 4 rows represents bits. With one set of fingers dragging across these rows, you would then get 4-bit data. With 4 bits of data available, this lens can indicate up to 16 different focal lengths.   By the way, there’s a similar circuit for determining the focus distance, but there are 4 rows of gold conductors instead of 5 rows. This gives 3-bit data, or 8 different focus distances saved into the EXIF data. The last row, similar to the focal length circuit, is just an electrical ground.     Summary   There’s a lot more going on inside a zoom lens than most people could appreciate. I hope this little tour helped clear up some of mystery of those inner workings.

This lens has the worst technical specifications of any lens I have ever owned. It has produced some of my favorite nighttime images. The TTArtisan 50mm f/0.95 leaves me perplexed. Photographers are supposed to purchase lenses based upon the best combination of technical specifications and price, unless you’re wealthy enough to just go by the specs. Sometimes, what a lens can produce cannot be defined by specifications.   I really, really like the look of the shots that I make at night with this TTArtisan. Nothing is needle sharp, but I find myself not caring about that. I do, as with all of my lenses, use the Topaz DeNoise AI software on the raw shots.   This lens is specified as ‘DX’, but I always shoot it as full-frame FX instead. Sometimes I crop the shot, but usually I don’t. It has the Nikon Z mount, and I shoot it with either my Nikon Z9 or Z8 camera. None  of the shots in this article are cropped from the FX frame.   Since this lens has no electronics, I have to program my camera to use it as “non-CPU”. This lets my camera get proper exposure, but it also lets the IBIS system work correctly by knowing the focal length. This is probably what I hate most about this lens; I wish it had at least some 'smarts'.   I almost never use any aperture except f/0.95. It’s the reason that this lens exists, really. 50mm f/0.95 1/80s ISO 8000, Nikon Z8 50mm f/0.95 1/3s ISO 8000 EV -4.9, Nikon Z8   I depend upon my camera IBIS system for vibration removal, and I’m able to easily take sharp shots down to around 1/3 second shutter speed. In the shot above, it was so dark that I could barely see anything until I looked through my viewfinder. I should probably use my Nikon Z9 instead of the Z8, since the Z9 has extra weight and therefore more inertia for those really slow shutter speeds.   I use the ‘low sensitivity’ setting on my camera “Focus Peaking” while I manually focus, which makes it really fast and accurate. If I owned the $8000 58mm f/0.95 Nikkor Noct lens, I do exactly the same thing, since it's manual focus, too. Lens field curvature is terrible outside of the DX area   The FX-format frame sides go kind of crazy with focus. A perfect lens would show a straight horizontal band in the shot above, instead of having sharp focus curve away from the camera. This is the main reason that TTArtisan calls this lens ‘DX’ instead of ‘FX’. I did crop the top and bottom of this shot, but the sides are full FX frame. I made this shot using the Photoshop Filter |Stylize|Find Edges  feature, shooting a flat lawn.   This lens also has a fair amount of barrel distortion, but if that bothers you, it’s easy enough to fix in an editor. The lens aperture ring produces very subtle clicks at each half-stop, but you generally need to look at the aperture scale to set it. This isn’t a problem for me, since I leave it parked at f/0.95, but many people would find it irritating. Coma is terrible on frame edges. f/0.95 shot.   Lens coma gets really bad outside of the DX frame. This wouldn’t be your first choice for star shots. 50mm f/0.95 1/80s ISO 8000, Nikon Z8   I wrote a technical article on this lens, which is located here 50mm f/0.95 1/200s ISO 6400, Nikon Z8 50mm f/0.95 1/80s ISO 8000, Nikon Z8 50mm f/0.95 1/80s ISO 8000, Nikon Z8 50mm f/0.95 1/80s ISO 8000, Nikon Z8 50mm f/0.95 1/50s ISO 8000, Nikon Z8 50mm f/0.95 1/80s ISO 8000, Nikon Z8   This lens is small and light enough that it’s easy to take it along on photo adventures with my other gear. If I don’t see any subjects that seem suitable, it’s no big deal. But I’m rarely disappointed with how this lens renders the right kind of subject. It’s hard to believe that a cheap lens with such terrible specifications can consistently produce pictures that have such an elegant look to them. It’s not technical, but this lens has, as the French would say, Savoir-faire .

Most modern autofocus lenses use stepping motors. Canon calls them “USM”, which is short for “piezoelectric ultrasonic motor”. Nikon calls them “STM” and “SWM”, while Pentax calls them “SDM”.   In 1961, Bulova watches invented the “tuning fork”, utilizing the piezoelectric effect for accurate timekeeping. Although interesting, nobody else had any ideas for using this microscopic vibration for anything useful.   H.V. Barth in 1973 proposed the theory of creating ultrasonic vibrations for motor applications, but didn’t do anything with the idea. In 1982, Toshiiku Sashida utilized the standing wave vibrations of ultrasonic piezoelectric motors for rotational motion. In 1985, Canon used Sashida’s technology to make their USM lenses, starting with their EF 300mm f/2.8. Good idea.   Piezoelectric motors are great for camera lenses, because they create high torque, they have great positional accuracy, and they’re energy-efficient and quiet. After Canon's 300mm lens came out, all of their competitors started paying attention.   The basis of the stepping motor operation is the piezoelectric crystal. This material expands when a voltage is applied across it. When the voltage is removed, the crystal returns to its original shape. The expansion is very tiny, but it’s enough to allow the crystal to push against another object and move it slightly.   Piezoelectric crystals can expand and contract very quickly, and they don’t waste much energy while doing so, either. This means that you can drive these crystals for a long time on a battery charge. It’s most efficient to drive these crystals at their “natural frequency”, where they expand to their maximum amount with the least energy. The rate of applying/removing voltage is about 30,000 times per second (30 KHz) at this natural frequency, or “resonant frequency”. The crystals only expand by something like 0.1% of their original dimensions, so they have to be very  close to the part that they push against. Each little push is a ‘step’, which is where these stepping motors get their name.   The ultrasonic motors are ring-shaped, with the crystals placed side-by-side around the ring (typically called ‘teeth’). Voltage is progressively applied/removed moving around this ring of crystals, creating what’s called a “standing wave”. This wave can be envisioned like an ocean wave that pushes a surf board along. In this case, the surf board is replaced with the moving ring of the stepping motor, whose rotary motion causes lens elements to move back and forth very quickly and accurately. These motors can run about 480 degrees/second (Canon specifications) with high torque, so they can focus a lens very quickly.   Many piezoelectric ultrasonic motors are connected to gears, instead of the large and expensive ring motors. These motors are very tiny and cheaper to make than the ring type. A Nikon SWM motor that drives gears for focus   In the shot above, the Nikon SWM autofocus motor uses the green stator to push against the silver-colored rotor to rotate a shaft connected to a gear train. The gears move a lens element group forward and backward along the lens axis to achieve autofocus. The green teeth in the stator of this motor are a piezoelectric material. This particular stator is 12 millimeters in diameter. The Nikon SWM motor and gear module How the motor drives the focus action in a Nikon SWM lens Canon ring drive USM stator Canon ring drive USM rotor Canon USM piezoelectric motor     I read an article by Douglas Kerr here  where he made a very useful diagram of the principle of how a USM motor works. The diagram below shows the expansion/contraction of the motor “stator” ring, which is the part that doesn’t actually rotate. The stator presses against the motor’s “rotor”, which is the part that spins around the stator. In the diagram, the rings are spread out flat, instead of being in a ring, or doughnut shape. Only the expanded part of the stator touches the rotor, while voltage is applied to that portion of the stator. How a piezo stator ‘tooth’ moves in time   In Douglas’ diagram above, the voltage progresses around the motor ring through the stator in an “electrical wave”, moving left to right. The piezoelectric material expands and then retracts in a wave motion, moving from left-to-right following the voltage. If you look at the highlighted green “tooth” on the stator, it moves upward and towards the left (steps 1-3). As the voltage is reduced, the tooth retracts from the stator and back to the right until it points vertically at rest (steps 4-5). The next wave of voltage starts the next expansion.   Due to the tooth’s motion while pressing against the stator, the rotor moves to the left, or in the opposite  direction from the wave induced in the stator.   The voltage can be applied in a wave in the opposite direction, which drives the motor motion in the opposite direction.   Each little tooth tip on the stator moves in basically an elliptical motion in response to the voltage wave. In the above diagram, it moves leftward while expanding and in contact with the rotor and then rightward while retracting and no longer in contact with the rotor. The net result is a leftward push on the rotor. Reversing the voltage wave direction will then reverse the motor’s rotor direction.   The motor’s rotor ring is a bit springy, so that the stator teeth don’t chew it up. As you might expect, there lots of little mechanical details that make the motor work reliably over many years without any maintenance required.   There are also several electrical details not covered here. For instance, the piezoelectric elements respond a little differently according to the ambient temperature and their variation in physical dimensions. Real motors have separate “reference” piezoelectric elements that are used in a feedback control system to adjust the controlling voltage frequency. Life’s complicated.   Toshiiku Sashida was one brilliant individual to have the vision to make these motors from the information he had to work with. Photography wouldn’t be where it is without him.