How it gets information in and out of the lens Sigma sells a USB dock (it looks like a hockey puck) tailored to your lens mount type. It’s cheap enough that you have no excuse not to buy it. The software is free from Sigma. It retrieves the connected lens model, mount type, serial number, firmware version, and customization settings using the Optimization Pro program. It sends firmware updates and any customization settings into non-volatile memory inside the lens. One dock will work with all of your Sigma lenses that support the USB dock (unless you have a mix of Nikon/Canon/Sigma/Pentax/Sony bodies). Older Sigma lenses don’t support this. Optimization Pro Features Firmware updates Update the algorithms for anti-vibration, focus speed, manual focus ‘throw’, and even future added features that haven’t been invented yet (such as focus fine-tune for different apertures on fast lenses? Are you listening, Sigma?) It lets you get any firmware bug fixes without having to send your lens to the factory, and it enables Sigma to alter any communications interface changes, in case Nikon or Canon get cute and try to make a compatibility-breaking change in the future. Tammy (sorry, I mean Tamron) and Tokina users might be out of luck if the lens communications requirements get changed in the future. The lens firmware version is checked when the program gets executed while the lens/dock is connected, so you don’t have to remember to request update checks. Focus Fine Tune For zoom lenses, it can calibrate focus at 4 distances for each of 4 focal lengths (16 total settings). The distances are (1) closest focus (2) near range (3) far range (4) infinity. For prime lenses, you can calibrate focus at 4 distances only. Now, even multiple copies of a lens can be custom-calibrated. Nikon, for instance, can’t tell the difference between two copies of the same lens model, and only knows a single fine tune number to apply. It’s very annoying when you have two camera bodies and you have to mark which lens to assign to which body (I paste the fine-tune value inside each lens cap, along with the lens serial number). Sigma can read its lens serial number electronically, so every lens is unique. Nikon and Canon et al. need to pay attention to details like this. Also note that lower-end cameras with no focus fine-tune can still get tuned lenses if they’re Sigma and use the dock. I think all AF lenses could benefit from this kind of focus fine-tuning intelligence. Real-world zoom optics need different fine-tuning at different focal lengths and different distances, but so far only Sigma seems to acknowledge this problem even exists. The 16 fine-tune settings for my 150-600mm Contemporary zoom Notice the different characteristics of each focal length shown in the “Focus Setting” fine-tune screen. The pathetic single AF shift value that my Nikon D7000 offers would leave the lens functioning very poorly indeed. The available shift range is plus/minus 20. Now I can finally leave my camera AF tune setting on “0”. I suppose a second camera body using this same lens would need a non-zero AF fine-tune value, but at least that would shift all 16 in-lens settings. Note the “Rewriting” button in the dialog box above that should say “Save” instead. Don’t be one of those people that get caught staring at this screen waiting for “Rewriting” to finish. I personally use MTF Mapper software and special focus test charts to evaluate critical focus. MTF Mapper is free; the author is Frans van den Bergh (this guy is absolutely brilliant). His program is available here: . This software lets me get really accurate information to enable me to enter good offset data into the Optimization Pro Focus Setting screen. MTF Mapper can also be used to evaluate lens sharpness, but that’s a topic for another day. It’s an iterative process to estimate the focus offset values to use, reprogram the lens with Optimization Pro, re-photograph the focus test charts, and then re-analyze the photos to see how you did. MTF Mapper uses “dcraw.exe” to decode RAW files, which is frequently updated for new cameras from most vendors. Focus chart analyzed and annotated by MTF Mapper program The above (unsharpened, RAW) photo shows one of the iterations to evaluate focus accuracy. This particular focal length and distance shows a focus error which will require the fine tune value to be decreased to pull the focus more toward the camera. The MTF Mapper web site also provides graphic files that have the test chart images for printing (both focus charts and resolution charts). I mostly use A0 size prints (about 33” X 47”) mounted onto a board; the bigger the chart, the better the results. I also print onto heavy glossy paper. Regular uncoated, lightweight paper sucks for trying to mount it and keep it totally flat. The more diffuse illumination you use when photographing the chart, the better. Also, you want bright light to give your camera focus system the most help (EV 10 or better for most cameras). Charts are of course useless for the “infinity” test shots. With long focal lengths, heat shimmer is a real problem. Maybe something like craters on the moon in cool weather would work best; I have used really distant tree branches or pine needles (600 – 900 feet) with the long focal lengths. Detail from the annotated focus chart created by MTF_Mapper_Gui program Profile view of the focus chart from MTF Mapper program The focus chart large vertical edge is depicted as the vertical blue line above. The smoothed plot of each measured square is depicted in green. Each individual square edge reading is plotted in red (units of MTF50 line pairs/mm). Focus is properly calibrated when the blue line aligns with the green peak. The above plot is from a test of the Sigma 150-600mm Contemporary lens at 600mm at f/6.3 using a Nikon D7000 camera. Note that a few edges actually measure over 40 line pairs per millimeter (and this is considered worst-case sharpness for this lens)! Focus testing was done using AF-C mode (with ‘focus’ button), and it is actually pretty repeatable. This is how this lens is mostly going to be used, so I tested it using the same focus mode. Test-to-test variation was pretty small. I shoot 10 shots at each focal length and distance, and then choose the average focus distance to decide how it is calibrated. By the way, the tested lens (150-600 Contemporary) had zero focus chatter in AF-C. The focus locked and stayed there on the target. This is very un-like my 70-300 Nikkor that chatters constantly, even in good light on high-contrast targets. It’s extremely annoying, and a deal-breaker for me. I read that the new Nikkor 80-400 AF-S VR has the same annoying focus chatter (see the review at photographylife.com). I used to think the chatter was a camera body problem, but now I realize it’s a lens problem. Chatter equals missed focus about half of the time, and focus fine-tune is an exercise in futility. But I digress. Full view of focus chart at 600mm at 19 meters (with annotation text). Note that the focus chart large ‘rectangle’ shown above is actually a trapezoid, to help counteract perspective. The large black ‘rectangle’ edge nearest the photo edge is actually much taller than the large edge in the center of the photo. The little squares are also farther apart vertically at the left edge than the right edge. Use high shutter speeds to eliminate any motion blur side effects; high ISO values have minimal effect on MTF measurements compared to motion blur, so don’t be afraid to push it to get blur-free pictures. I also use my infrared remote unit with mirror lock-up to rid vibrations, in addition to a big-honking tripod. Just remember: “garbage in, garbage out”. It’s worth your while to do careful focus calibration. If you read reviews of a Sigma lens that supports the USB dock but the calibration wasn’t done, then don’t put too much stock in the review in regards to focus accuracy. In this case, the saying goes “nothing in, garbage out”. I don’t see any fundamental reason why Sigma can’t do all of this focus calibration at their factory, but talk is cheap here. Hey, at least they’re giving us the tools to help ourselves. No other manufacturer is even close to this level of sophistication (yet). There a bunch of videos here from a Canadian company that go into detail about using the Sigma software and Sigma topics in general. #howto

The exiftool program lets you extract all of the data out of your photographs into a text file by a simple drag-and-drop operation. This is a really easy way to get at exposure, lens, and camera data, plus much more. You can find out how many total shutter-actuations your camera has done, the “Light Value” (or EV) of the scene, the depth of field, whether you used phase-detect or contrast-detect, etc. What you can’t get is the Nikon lens serial number, although you do get the camera serial number. It’ kind of cool that my Sigma 150-600 Contemporary lens data even gets correctly decoded while on my Nikon. I can give it my RAW files directly, plus a bunch of other formats. You can get this free program here: The author is Phil Harvey. Please thank him! Thank you, Phil. Phil’s software can do many things beyond what I mention here, but here’s how I use it in Windows (Mac OS-X is supported). Select the exiftool.exe file in Windows Explorer Right-mouse click and select Copy and paste into the same directory. Right-mouse click exiftool –Copy.exe and rename it: exiftool(-a -u -g1 -w txt).exe Now, all you have to do is go to a directory with photos and drag/drop a file onto the exiftool(-a -u -g1 -w txt).exe program. You will get a text file (same name as the dropped file, but with a .txt extension) placed right next to the original photograph file. Simple and elegant. Sample Data From Typical Output Text File This program is really, really useful. It's also a real eye opener to know just how extensive the amount of data kept in every photograph really is. Thank you Phil Harvey! #howto

What can you expect from a lens when you change to a higher resolution camera? For crummy lenses, don’t expect improvement. Good lenses, though, are another story. Let’s compare the Nikon D7000 (16 megapixel) against the D7100 (24 megapixel) cameras. The D7000 sensor is 3264 X 4928 pixels, while the D7100 is 4000 X 6000 pixels. Both sensors are the same size, at 15.6 mm X 23.6 mm. Resolution change is evaluated in a linear fashion, so it’s the change in the ratio of either the short or long edge measurement of the sensor, such as 6000/4928 = 1.22, or 22 percent more with the D7100. Doesn’t sound nearly as sexy as 24MP/16MP = 1.5 or 50% bump, does it? If a lens has good enough optics, then you would expect your MTF50 measurements would therefore increase by about 22% by upgrading from the D7000 to the D7100. But wait, there’s more! What about that removal of the OLPF (optical low-pass filter) on the D7100? At the risk of moiré in some pictures (never actually observed by me in any of my pictures yet except for shooting a “Siemen’s star” target) you can squeeze a bit more resolution out of a sensor when you stop fuzzing-out the image by getting rid of that low-pass filter. Low-pass (e.g. don’t pass high-frequency light/dark transitions) filters stop those nasty color patterns you used to see watching TV when some guy would wear a pin-stripe suit. If the pinstripes were spaced at the same interval as the camera sensor elements, it really messes up the image. The OLPF filters work by de-focusing the image a little bit, and therefore ruins those fine details in your carefully-focused picture you paid big bucks to get. You get the lost resolution mostly recovered by using the “un-sharp mask” in your favorite image-processing program. It always seemed a real hoot that “un-sharp” was used to get “sharp”. Another way to get rid of moiré is to use the "moire removal" feature in many modern image-processing programs designed specifically for that task. In any event, moiré is a “don’t care” for most people and most photographs. After that major digression, let’s get back to lens resolution and camera sensors. We’re expecting about 22% improvement in MTF50 measurements, not counting the OLPF filter removal. This assumes the lens resolution isn’t already maxed-out on the D7000. MTF50 results for Sigma 150-600mm lens on D7000. MTF50 results for Sigma 150-600mm lens on D7100. Using the above Sigma lens results, we get a MTF50 high-reading change from 40 to 48, or about 48/40= 1.2 = 20%. On the low end, the change is from 26 to 30, or 30/26=1.15 = 15%. Next, let’s check out my best-resolving lens: MTF50 results for Nikkor 85mm lens on D7000. MTF50 results for Nikkor 85mm lens on D7100. Using the above Nikkor 85mm f/1.4 AF-S lens results at f/4.0, we get an MTF50 high-reading change from 54 to 68, or 68/54 = 1.26 or 26%. On the low end, the change is from 46 to 52, or 52/46 = 1.13 or 13%. Conclusion If you have a pretty good lens, you can expect to get nearly the theoretical maximum resolution change. It’s unclear (no pun intended) the contribution of the OLPF filter removal to overall resolution, but I’m getting around 26% overall (camera sensor plus OLPF removal). The OLPF removal must be at least 4% improvement. Corners aren’t quite as rosy of a scenario, but still a substantial improvement. BTW, don’t abandon the un-sharp mask when post-processing just because you don’t have the OLPF filter. You’ll still see a huge bump in sharpness. #howto

I want to present details on the lens MTF50 resolution performance and how well the lens autofocuses. I won’t rehash the Nikon specifications of the lens, since that data is readily available in any number of other places. My usual disclaimer: this is looking at a single copy of the lens. Yours will be different, but hopefully ‘similar’. The only place I know of that tests lots of copies of lenses is here. I’d also like to mention some comparisons to the 60mm f/2.8 Micro Nikkor AF-D. There is a lot of talk on the internet about how totally inferior the 60mm is to the 105mm. I personally think that the 60mm is more competitive than people think it is, even with its lack of VR compared to the 105. It’s true that you have more working distance between the lens and subject (6 inches versus 3 inches at 1:1) using the 105mm, but often that extra distance isn’t really needed. The working distance goes down to 2.75 inches at 1:1 magnification if you use the 105 lens hood. These tests were done using a Nikon D7100 (24 MP) with unsharpened 14-bit compressed RAW format. Here is a link to get pretty good information on this lens. They reduce resolution measurement down to a single number for an f/stop setting. It’s not that simple; resolution is a 2-dimensional thing. The focus ring on this lens is nice and wide; nobody can complain about that. You can use it anytime you want to override autofocus. Many people use this lens in manual focus mode only, and only use the focus ring to set the magnification before moving the camera/lens back and forth to focus on the subject. You get a rear rubber dust gasket, but that’s it for moisture/weather sealing. Nikkor AF-S Micro 105 mm f/2.8G IF-ED VR with Nano-Coating Autofocus Phase-detect focus was very fast on my D7100 in dim light, and very repeatable. I also noticed that Live-view shot-to-shot resolution measurements had almost zero variation; the lens focus motor is really first-rate. There was absolutely no focus chatter, and that’s crucial (lenses that have focus chatter are useless, in my opinion). I noticed no focus calibration shift at different f/stops. Focus was basically silent (unlike my micro Nikkor 60mm f/2.8). I don’t have a single lens that doesn’t need some focus fine-tune calibration. This lens is no different. If your camera doesn’t have fine-tune, you need to save up and buy one; refurbished cameras are pretty reasonable these days. Your lenses won’t be giving you what you paid for without fine-tune, unless you put up with Live View autofocus. I guess you can manually focus, too (I personally gave up on that the day I got an autofocus lens). Vibration Reduction (VR) This has first-rate VR, which is one of the biggest upgrades over my 60mm f/2.8 AF micro Nikkor. Resolution Testing Now for the real meat of this article. You will get to see the full 2-dimensional resolution of this lens, separated into both sagittal and meridional values. Here’s my customary rant about those lens reviewers that grade lens resolution with adjectives like “good”, “fair”, “excellent”, or “1.5 blur units”. Huh? I want real numbers and I want to see real pictures of things I’d actually bother to photograph. I use a (free!) program called MTF Mapper from here to measure lens resolution. The download site also has files for printing out the resolution targets (mine are A0 size on heavy glossy paper (‘satin’ finish seems to work just as well), dry-mounted onto a board). This program is covered in more detail in another article, but suffice it to say that this is really great stuff; it’s comparable to ‘Imatest’ in the quality of the MTF measurements, and it uses the “slanted edge” technology similar to ‘Imatest’, also. The author of MTF Mapper, Frans van den Bergh, really knows his stuff. Visit his site and give him the praise he deserves. The chart design used for resolution tests orients all of the little black squares to be ‘slanted’ but they’re generally aligned in meridional and sagittal (think spokes on a wheel) directions to correlate better with the usual MTF plots you’re familiar with. There’s often a dramatic difference in sharpness between these two directions, and the chart photographs show it clearly, when it exists. The meridional/sagittal differences are what “astigmatism” is all about. This lens isn’t perfect in that regard, but it’s better than most. What the resolution target looks like. Mine is mounted ‘upside down’. At long last, I’m getting around to some actual resolution results. Tests were done with “Live View” AF-S autofocus, contrast detect, IR remote, VR OFF, really big tripod. That’s how I get around any phase-detect problems with focus calibration. The results don’t seem to improve using manual focus and 100% magnification in Live View, so I don’t bother. I use the “best of 10 shots”; not every shot gets the same resolution results. All cameras operate on the “close enough” principle for focus, so many tests are needed to determine the best resolution that the lens can produce. That said, this lens was so repeatable that they were all just about the same sharpness. Wide open. Already impressive resolution, all the way to the edges. Peak sharpness at f/5.6 These numbers bring tears to my eyes. Diffraction setting in at f/8, but still excellent. Resolution Summary Pick an f/stop according to desired depth of field. You needn’t bother about trading off sharpness with f/stop. Diffraction starts at f/8, but there isn’t that much of a resolution penalty until about f/16. Some people refer to a lens with good resolution and contrast as having 'bite'. This lens has big-dog bite. If you can afford it, get it. Sample Pictures Humming bird warning me I’m too close. 105mm Micro Nikkor, 1/60, f/8.0, flash. I combined sharp flash with ambient light at a slow shutter speed to make it a bit more interesting. Detail from above. This is one sharp lens. Hummer posing. I normally don't display blah images like this, but note how SHARP it is. Feather details. #review

This is the Tokina version that uses the screw-drive for auto-focus. It has the same optics as the newer internal-focus motor “Pro II” version. The newer version also claims to have improved anti-reflection coatings. I have read that some users find the newer “Pro II” to be less sharp than this original version, but I suspect it’s just lens sample variation they’re seeing. I’ll concentrate on the lens resolution performance in this article, in addition to my observations on any unusual behavior I have noted in using it. Some people are averse to lenses that use the “screw drive” focus, but for me it’s basically a “don’t care” when the focal length is small (e.g. non-telephoto). Focus is still plenty fast (camera model dependent) and actually one of my more repeatable lenses for phase-detect focus. An interesting thing I noted on focus is that the “live view” autofocus wasn’t consistent. This is the exact opposite of what typically happens with other lenses, where the “phase detect” is less consistent. I got such consistent results with phase detect that I used it for the resolution tests and got absolutely repeatable results. Since I only have one copy of this lens, I can’t say if you will see this effect or not. Although it’s a “DX” lens, it has full frame coverage on FX at the 15mm-16mm lengths. I’ve read that corners are fairly soft on FX, but I haven’t tested it. Update 6-10-2016: I have tested it on a Nikon D610. It's very good at 16mm, but I don't like the level of vignetting at 15mm. See the my review here. Tokina built this lens for professionals, so it’s a metal and glass hulk. It’s actually quite beastly in size and weight. It uses 77mm filters; I keep a UV filter on it, mainly because the front element is challenging to clean due to its substantial curvature. What you get for that big diameter: f/2.8 and constant-aperture while zooming! What you don’t get: vibration reduction. Not such a big deal on short focal lengths, however. These tests were done using a Nikon D7100 (24 MP) with unsharpened 14-bit compressed RAW format. I actually left the UV filter ON for the tests; the filter doesn’t have any measureable effect on resolution results. I’ll let the pictures at the end of this article speak for themselves in regards to the anti-reflection coating and contrast. Yes, you’ll get internal reflections to show up when you point it at the sun; you will get flare when you “provoke it”, so don’t provoke it! The lens also has a proper metal lens mount and gasket (rubber seal). That’s it as far as dust/weather resistance is concerned. I read plenty of complaints about the focal length range only going from 11 to 16. I bought this lens for 11mm, so I really don’t care about how ‘long’ it can get; you’ll have to decide if this is important to you or not. You can bet that a longer focal length range would result in more optical problems. I am very pleased with the optical quality of this lens. It would be nice if the corners were a bit sharper, of course. But when you compare it to the competition, you’ll see that the corner performance is actually first-rate. Note that in the resolution plots below you can get really good corner performance when you stop down. Although this is a rectilinear lens, you’ll notice barrel distortion, particularly at 11mm. Since you can correct it using your favorite image editing software, it’s not a big deal. For landscapes, it is a total non-issue about 99% of the time. I bet you won’t even notice distortion when you get to 16mm. What I didn’t notice was vignetting, which surprised me. Take a look at the sample photos at the bottom. Make it disappear with your image editor if it bugs you; same goes for any lateral chromatic aberrations. This is a really great video lens. If you mess with focus while shooting video, you’ll want manual focus; it works by pulling the focus ring toward you to engage a clutch. I didn’t notice any focus breathing (grow/shrink image size with focus change), either. It also appears to be “parfocal”, so you don’t need to refocus after zooming. Tokina 11-16mm f/2.8 with removable lens hood (plus 77mm UV filter). Resolution Testing This is why you should read this article. My goal is to enable you to evaluate resolution between lenses in a standard, scientific way. I also give you the information (see my MTF Cliff’s Notes article) to be able to repeat these tests for yourself. Resolution measurements are in MTF50 lp/mm. This measurement represents how many image line pairs can fit inside a millimeter before the white-to-black chart transitions degrade to 50%; e.g. “turn to mush”. For me, anything beyond about 30 lp/mm is fine, and beyond 50 is outstanding. Higher-resolution sensors yield higher measurements, much like you’d expect. Before I forget, you will notice a couple of tiny weird blobs in some of the resolution plots that follow. Please ignore these, since they are definitely not a lens imperfection. The measurement software is extremely sensitive, and an imperceptible chart surface indentation shows up very clearly in the measurements. I use a (free!) program called MTF Mapper from here to measure lens resolution. The download site also has files for printing out the resolution targets (mine are A0 size on heavy glossy paper (‘satin’ finish seems to work just as well), dry-mounted onto a board). This program is covered in more detail in another article, but suffice it to say that this is really great stuff; it’s comparable to ‘Imatest’ in the quality of the MTF measurements, and it uses the “slanted edge” technology similar to ‘Imatest’, also. The author of MTF Mapper, Frans van den Bergh, really knows his stuff. Visit his site and give him the praise he deserves. The chart design used for resolution tests orients all of the little black squares to be ‘slanted’ but they’re generally aligned in meridional and sagittal (think spokes on a wheel) directions to correlate better with the usual MTF plots you’re familiar with. There’s often a dramatic difference in sharpness between these two directions, and the chart photographs show it clearly. The meridional/sagittal differences are what “astigmatism” is all about. This lens is decent in the sagittal direction when you get away from the lens optical center. Meridional direction isn’t nearly as good; this is the “norm” in most lenses. The middle of the lens is beyond impressive, as you’ll see. What the resolution target looks like. Mine is mounted ‘upside down’. Finally, I’m getting around to some actual resolution results. Tests were done with phase-detect back-button autofocus, IR remote, and a really big tripod. As I mentioned before, this lens likes phase-detect better than contrast-detect focus. I use the “best of 10 shots”; not every shot gets the identical resolution results. All cameras operate on the “close enough” principle for focus, so many tests are needed to determine the best resolution that the lens can produce. MTF Mapper “focus target” plot. Note the “+15” fine-tune for phase detect. Focus fine-tune was set to +15 to calibrate this lens to my D7100. Take a look at my MTF Mapper Cliff’s Notes article if you’re curious about the details. The lens is so wide that I had to have my A0 target at only 1 meter away. Distortion Analysis Worst-case distortion at 11mm showing the resolution target Same 11mm photo after software distortion correction 16mm uncorrected distortion. I don’t see any distortion. Resolution Results The following measurements were done at the extreme focal lengths of the lens. 11mm wide open. Great center, corners not very good. f/5.6 has outstanding center, and now corners are quite good. Diffraction is killing resolution at f/16 16mm wide open. Again, corners aren’t that good yet. f/4.0 has exceptional center, and corners are now fine f/16 and diffraction is again killing resolution f/22: Don’t go there. Sample Pictures Great for emphasizing the foreground. 11mm Drinking Dragon (Los Arcos). 16mm. #review

One of the more obscure features offered by the Nikon D850 is the ability to directly convert your color or black and white film negatives into digital positives. There are of course companies that still offer to convert your film to digital, but many people want to do this activity themselves. The file output format created by the D850 when using the “negative digitizer” is strictly jpeg, even if your camera is set to record as NEF. A word of caution: this feature is unavailable if your camera settings are configured to use live view “silent photography”. The “Negative digitizer” option will be greyed-out if this mode is active. D850 with Negative Digitizer active You don’t have much control over the photograph in-camera; you can’t even control the colors. You’ll need to provide good lighting, such as normal daylight, for the conversion to be successful for color negatives. You can adjust the brightness, if needed. Please, please dust off your negatives first; the healing brush in your editor gets really tiresome. Gear Selection Nikon PB-4 Bellows and PS-4 slide copy adapter I have the Nikon PB-4 bellows and the Nikon slide copy adapter PS-4 that fits onto it; this is still the Cadillac system for copying filmstrip negatives and mounted slides, in my estimation. I also use my old Micro-Nikkor 55mm f/3.5 pre-AI lens, which is absolute perfection for life-size copying of film with this bellows and slide copy attachment. I had to remove my vertical battery grip from the camera to mount it onto the PB-4. I also had to place the PB-4 camera mount into vertical orientation to attach/detach the camera; once attached, I could rotate the camera into the horizontal (landscape) orientation. Additionally, I had to move the rear bellows back to its end of travel on the rack to attach or detach the camera. You need diffuse, even lighting to illuminate your film; the slide copy adapter provides exactly that with milky white glass behind the negative, which also keeps the film flat. I use a wired remote release, to eliminate any vibration concerns. Copying Procedure Once your have your negative mounted in front of your camera, you’ll first need to switch into Live View. Make sure you’re using a good full-spectrum, “daylight-balanced” light source. Zoom in (the “+” button) to make sure that your negative is properly focused (with a wide-open aperture). I like to use the Live View “focus peaking” feature to make manual focus much simpler. Step down the aperture to the sharpest setting (e.g. f/8.0) after focus is confirmed. Next, press the “i” button and choose the “Negative digitizer” option, which will either have a “CL” or “MC” icon displayed to indicate this option. Press the “up/down” multi-selector to get to the icon. The camera remembers the last digitizer mode you had selected. The two options for using this feature are “CL” for “color negative” mode or “MC” for “monochrome”. Press the “right arrow” to select the color/monochrome screen, and then press the “up/down” arrows to select which CL or MC option you want. Press “Ok” after the color/monochrome is selected. Your exposure mode will be automatically set to “A”, and you cannot change it. Press the “Ok” button, when prompted, to adjust the brightness, and then press “Ok” after finishing your brightness adjustment. Take the shot. Live View with an old “orange film” color negative I always thought that the old orange color negative film looked particularly terrible. I never fully understood the necessity to add the awful orange cast to everything, including the film edges. Negative Digitizer “CL” mode When you enter the CL mode, the view you get is worlds better than the orange and purple “negative” view. Live View with a black-and-white negative Notice the little red “focus peak” marks on the LCD; this makes critical manual focus much simpler. Negative Digitizer “MC” mode The “positive” view of your negative in MC mode is slightly different than the recorded image; the recorded image is definitely better. Finished photo from color negative conversion Color negative film doesn’t age nearly as well as black and white film. The shot above is from 1993. There’s not a lot that can be done to fix fading, but at least the digital version will stop any more fading. Maynard Ferguson, 1976. Converted from film negative. I’m impressed by how faithfully the black and white negatives get converted into positives. The tonal range seems excellent to me. That being said, working with these film negatives reminds me how modern digital sensors totally smoke film. More tonal range, more sensitivity, and more resolution. I made the shot above with a Nikon F2 and Nikkor 300mm f/4.5 lens (and these still perform as well today as the day I bought them). If black and white film is properly developed and stored, it can last multiple lifetimes. There doesn’t appear to be any change to this negative over the 44 years of its existence. I remember that I used Tri-X pushed to ASA 1600 for this concert (ISO used to be called ASA). Conclusion The Nikon D850 provides a simple way to see and photograph your negatives as positive images. Since it only provides jpeg output, you don’t have as many knobs to adjust the output as you may be accustomed to having available when shooting Raw. Most of my old color film work was done with slides; I always disliked color negatives. If all you have is color negatives, here’s your chance to convert them to digital before they fade away. Go ahead and convert those slides while you’re at it, even if you don’t need the “Negative Digitizer” feature to do it. I have always had an affinity for black and white, and I have a huge body of work done with film. I think that this D850 feature works really well for converting those negatives into digital positives, without much loss of sharpness or tonal range. I’m really glad that Nikon added this little-advertised feature to the D850. We need to praise and encourage the Nikon engineers for thinking up new ways to expand the power and usefulness of their cameras. It’s a comfort to finally have some backups for my film negatives. I admit that I’m way past due in getting this done; my video tapes got digitized years ago, but I neglected my stills. And rest in peace, Maynard.

Short answer: heck yes. But it depends. This is one of the internet topics that go round and round with lots of hand waving, but not much to back up opinions. I decided to test it for myself. Turns out that it's a bad idea if you don't turn off VR with high shutter speeds. You’ll lose about 9% of resolution with your shutter at 1/1000 if you leave vibration reduction (VR) ON. Turn it off if you go above 1/1000! It's lens-dependent in the range between 1/500 and 1/1000. My Sigma 150-600 generally works best with vibration reduction ON between 1/500 and 1/1000. BUT not all lens VR is created the same. The Sigma 150-600 firmware update 1.01, for instance, seems to have changed this story. VR works with higher shutter speeds in this case. Same goes for the Nikkor 24-70 f/2.8 VR; you can use higher shutter speeds at least with these lenses. Check out the link here for more. Present technology in vibration reduction can only run up to so high of a frequency, and that limit corresponds to about 1/500 second. Beyond that shutter speed, it actually hurts more than it helps. Below that speed, it can be an amazing aid to keep pictures sharp. I tried some tests using the Sigma 150-600 Contemporary at 600mm, 1/1000, f/6.3, ISO 2000, using the factory image stabilization (OS) algorithm. I used the 'overall' image stabilization, versus the 'panning' stabilization algorithm, since the viewfinder image showed the subject moving as much vertically as horizontally. The basic idea is the same for Nikkor lenses with "VR", although you don't get as many options for VR algorithms as Sigma provides. I set the lens onto a tripod with a gimbal mount, but I left the gimbal adjustments loose and held onto the Nikon D7100 and used AF-C while I tried to train the focus sensor on the middle of my resolution target at about 55 feet. These are typical shooting conditions, where the subject is jumping around in the frame and you'd swear that VR would be a good idea. Here's the first set of test results: VR (OS) ON while shooting the target with AF-C (using back-button focus). MTF50 Max. MTF50 Min. (corners) 46 28 46 30 46 28 44 30 46 30 44 30 38 30 44 30 42 30 42 28 44 28 34 22 Average maximum resolution = 43 lp/mm Average minimum resolution = 28.67 lp/mm (corners) Here's the second set of test results: VR (OS) OFF while shooting the target with AF-C (using back-button focus). 44 30 48 30 48 30 48 30 46 32 48 30 46 30 46 30 45 30 48 30 Average maximum resolution = 46.7 lp/mm Average minimum resolution = 30.2 lp/mm (corners) Comparing the two tests: 46.7 / 43 = 1.09 = 9% sharper with VR OFF while using 1/1000 shutter. 30.2 / 28.67 = 1.05 = 5% sharper with VR OFF (corners) using 1/1000 shutter. Also, notice that the results vary more when using vibration reduction at high shutter speeds. Therefore, don’t use VR going beyond 1/500 shutter! Unless your own tests of a specific lens indicate otherwise, that is. Life is so complicated. #howto

This review is primarily concerned with resolution. The Nikkor 60mm f/2.8 AF-D seems to have a mixed quality reputation among users. My copy of this lens is really, really good in the center. Corners aren’t so hot until f/5.6. This is an older lens (1993-2008), but it’s built to very good mechanical standards. Note that you will need an upper-end camera body that has a built-in focus motor to use this lens. It’s an “FX” lens, so it will work on full-frame models. I have read lots of reviews where they complained about its short focal length, but on a DX camera I have rarely had any issues with a too-short lens-to-subject distance. This includes many butterfly shots; lighting isn’t a problem, nor do I have much of an issue with scaring bugs away. I generally use an SB-600 flash and “FP” mode outdoors for close-ups with high shutter speeds. I have a separate article on “FP” mode if you’re interested. Please, please don’t use the camera built-in flash. If not for you, do it for sake of art. I have always liked this lens for portraits, too. On DX, the focal length is quite nice. The 2.8 aperture might be considered a limitation for portraits; it’s a matter of your own taste. I’m not saying it’s going to replace my 85mm, but before I got my 85, the 60 was the go-to lens for portraits. Autofocus isn’t perhaps blazingly fast, but it’s not a problem. Maybe it’s just me, but I still like having autofocus available when I’m shooting close-up and hand-holding the camera. Judging sharpness with manual focus just isn’t for me. There’s a “focus limit” switch for quicker focusing at non-macro distances. If you’d rather do manual focus, then press the little chrome "unlock" button on the lens barrel and then rotate the "M - A" ring to “M”. Most people obviously use macro lenses for close-up photography, and I’m no different. I almost always use a flash, and I stop the lens down for depth of field. A bonus with stopping the lens down is resolution; you’ll see below how dramatically the resolution across the frame improves at smaller apertures. Resolution peaks at f/8.0, and then diffraction rears its ugly head after that. The lens focuses down to 1:1 magnification. If you like to standardize on this level of magnification, you may want to consider other lens options that aren’t going to be as challenging for lighting and lens-to-subject distance. It’s only about a 3-inch gap from the front of the lens to your subject at 1:1 magnification! If you want to go through the pain of evaluating your own stuff, then you need to get the MTF Mapper program and print out the resolution target files at that site. The software (as of this writing) is free, and the author Frans van den Bergh is to be commended. The download site is here http://sourceforge.net/projects/mtfmapper/ I discuss using his program in another article. The article is a ‘Cliffs Notes’ version with enough detail to get you started, but without the finer points being included. You really should give Frans’ stuff a read, however, if you want to understand the technology it contains. MTF50 Measurements I measure lens resolution at MTF50. Most published manufacturer MTF charts are at MTF10 (contrast) and MTF30 (resolution). Except for maybe Zeiss and Leica, those MTF charts are “theoretical”, meaning they don’t have much basis in reality. And they don’t ever show the whole frame, which is the only decent way to evaluate resolution. The "MTF" refers to Modulation Transfer Function, which refers to how light/dark transitions happen. "MTF50" refers to the highest line frequency (line pairs per millimeter) you can have before 50% of the contrast is lost. Values above about 30 lp/mm are considered pretty good, and anything above 50 lp/mm is outstanding. I made the tests with a Nikon D7100 (APS-C sensor, 24MP). Bear two things in mind; corners for FX will be worse and other camera resolutions will get different MTF50 values. For instance, the D7000 gets up to 24% less resolution (I tested it). Lesser lenses will show a smaller improvement with higher-resolution sensors, because the lenses aren’t as capable. What the resolution chart looks like The picture above shows what gets photographed (unsharpened, RAW) and evaluated. The program author, Frans, has a couple of chart designs, but the main idea is to align the little squares to get their edges in sagittal (spoke) or meridional (tangent) directions. The squares need a little ‘slant’ to them (5 degrees is optimal) to get measured optimally, similar to what Imatest does. Measurement algorithm problems arise if the little square orientations approach vertical or 26.565 degrees. If you try testing yourself, don’t get too sloppy about orienting the chart, and bear in mind that the squares must always be bigger than 25 pixels on an edge. The chart squares emanating from the center along 45 degrees (“X”) have MTF readings that can be 2 or 3 percent higher than they deserve. This is the tradeoff between the desire to get sagittal/meridional measurements and approaching the critical ‘bad’ slant angles. The Imatest guys have punted on this and don’t align their target squares in sagittal/meridional directions; they have 5-degree slants on all of the squares. You’ll see an “X” pattern on some of the 2D resolution plots below, due to this effect. Resolution Tests MTF50 60mm f/2.8 wide open This is really good performance for being wide open, in my opinion, but NOT in the corners or edges. Note that the EXIF data got messed up for “focus distance”. The tests were done with an “A0” chart size. I don’t have a really good small-sized resolution chart, so tests were done at more conventional distances. Limited testing I tried at closer distances didn’t show resolution improvement, although urban legend says macro lenses improve resolution as you get closer. 60mm f/4.0 MTF50 Notice you get an immediate 40% jump in resolution going from f/2.8 to f/4.0 (just a one-stop difference) in the corners. Again, this is only one copy of the lens being tested; no guarantees on how yours might perform. Only a 9% resolution increase in the center, but resolution was already stellar at f/2.8. 60mm f/5.6 MTF50 I’m getting another 29% resolution jump going from f/4.0 to f/5.6 in the corners, but I didn’t see center improvement; it’s already so good that I can’t complain. 60mm f/8.0 MTF50 This brings tears to my eyes. I’m so proud of this lens! Peak performance everywhere in the frame. This is the aperture to even start to have sufficient depth of field for most close-ups. 60mm f/11.0 MTF50 Diffraction starts at f/11. Still great resolution, so don’t feel you need to avoid this aperture. Beyond f/11, resolution suffers quite a bit. The lens goes to f/32 (f/57 at 1:1 magnification!) for those subjects where depth of field needs to trump resolution. Conclusion I have compared this lens to the 105mm f/2.8 AF-S VR Micro Nikkor, and it is actually sharper in the center than the 105 (by 13%). The 105 smokes it in the corners until f/5.6, though. Again, this is only looking at a single copy of each lens. Both are fine lenses, but the 105mm costs way more. I love my 60mm; it’s a true classic and I have no intentions of giving it up. Now let’s talk about un-sharp corners at f/2.8. Depth of field approaches zero at that aperture when doing actual macro photography. I would virtually never use the lens that way, so corner performance at f/2.8 is a “don’t care” for me. It is only useful for seeing a bright image through the viewfinder and enabling the camera to focus faster. It should be one of the last considerations for buy/no buy decisions unless you’re into astrophotography. Samples Butterfly 60mm f/10, 1/320, ISO 100, SB600 Flash Butterfly 60mm f/7.1, 1/500, ISO 200, SB600 Flash FP mode Lizard Fight 60mm f/18 1/60 ISO 200 Flash Don’t fear stopping down! Sufficient depth of field far outweighs resolution to capture important subject matter. #review

Nikon ML-L3 Infrared Remote Don’t have your Nikon ML-L3 IR remote handy? No problem. Did you know that there are programs that you can download for your smart phone and use its infrared capability to trigger your camera shutter? You can even get more capability than the ML-L3 has, such as timed triggering and sound options. You can also select other camera remote identities, such as Canon, Olympus, and Sony. I downloaded Camera Remote Control from Dev Null using Google Play, but there are other choices as well. How cool is that? When I use a tripod, I always trigger the shutter with an IR remote. I configure (via the camera "Shooting" menu) the "Remote control mode (ML-L3)" and set it to "Remote mirror-up". The first press of the remote (or on the phone app) will raise the mirror, and the second press will release the shutter. This way, you can wait for vibrations to die down before releasing the shutter. #howto

Did you know that when you set your Nikon camera to manual exposure mode that your flash is still on automatic exposure? Why should you care? This happy combination of manual camera exposure and auto flash exposure is a big deal to me. Your main subject can be well-exposed by the flash, while the ambient light in the background can be controlled by how you set the manual exposure. Nothing screams amateur like indoor flash shots with jet-black backgrounds. If, instead, you expose the background about 1 to 2 stops under (using the camera meter), then your main subject can be exposed properly by the flash while the background (which is out of range of the flash) is pleasingly de-emphasized. If you use “FP” mode on your external flash, then you can even use this technique outdoors at whatever shutter speed and aperture combination that suits the scene. The flash “FP” mode allows any shutter speed, while filling in those nasty shadows in someone’s face under their eyes and nose. Your subject, of course, needs to be within range of the flash. The camera internal flash cannot be set to FP mode. Canon calls it HSS (High Speed Sync). Lower-end cameras may not offer this feature. If you set “Auto FP” mode for your external flash, then it’s a set-and-forget scenario. Your flash will go into FP mode when you set a high shutter speed, or else stay in the usual high-power-short-flash-duration mode with lower shutter speeds. My cameras are always configured this way. FP mode uses a series of quick flash bursts while your shutter is open, so it’s like continuous light. The quick bursts overlap each other just enough to seem like the flash is on the whole time the shutter is open. Any motion-stopping capability only resides in the shutter speed you use and not the flash. Be aware that the overall light intensity is reduced, so your flash won’t have the usual range. Expect to lose about 2 stops of flash intensity. Here’s a good resource on flash here. In case you’re wondering, “FP” is short for “focal plane”, and it really has nothing to do with an electronic flash. It alludes to special old-time “FP” flash bulbs that had long-burning characteristics, so that they would burn the whole time your “focal plane” shutter was open. This mode emulates that same long-burning flash bulb. You might need a neutral density filter if you’re using a really wide aperture in the sun, but the flash fill light really makes your subject pop (it adds that sparkle to the eyes). Please use bounce flash or a flash diffuser indoors when you can, or you risk getting those nasty hard shadows you really don’t want to see. Even the old lens tissue over flash with rubber band can be really helpful if you can’t use bounce. Diffusing the light will rob even more flash power, however. I guess that’s why they sell those powerful pro flashes. Macro photography outdoors using flash FP mode and manual exposure is a marriage made in heaven. It’s the cat’s pajamas. It’s the bee’s knees. You get the picture. Yet another pun, sorry. To summarize, when you set your camera to “manual”, you use it set the background (ambient) exposure to your taste. The flash will (usually) handle the foreground subject exposure. Check out a real pro like Neil van Niekerk here to appreciate what flash photography can do for you. I’m not worthy. Samples of Using Manual Exposure and Flash FP Mode 1/640, f/8.0, manual exposure, Auto-FP mode, Nikon SB-600, D7000, Nikkor 60mm f/2.8 AF-D. 1/1000 f/6.3, manual exposure, Auto-FP mode, Nikon SB-600, D7100, Sigma 150-600 C at 600mm. The subject would have been a near-silhouette without flash here. #howto

The bulk of this review will concentrate on the lens resolution. The Nikkor 85mm f/1.4 AF-S is considered by many to be the gold standard for Nikon lenses. It not only has outstanding resolution, but it also produces among the best out-of-focus characteristics (bokeh) of any existing lens. This combination, in addition to its perspective at 85mm, makes it the ideal portrait lens. One of the few complaints (other than cost) about this lens is that it doesn’t have vibration reduction (image stabilization). As of this writing, none of the major manufacturers have a fast prime 85mm lens with stabilization. It’s probably non-trivial to maintain the premium optical characteristics and add vibration reduction. Due to its nano-coating, this lens is very resistant to flare. Even still, a lens hood is always recommended. Nikon, as just about everybody knows, also makes an 85mm f/1.8. I don’t own this lens, but it is said to have at least comparable resolution to the f/1.4. People who buy the f/1.4 primarily get it for the ability to obtain a very thin depth of focus wide open, with world-class bokeh in the background. Autofocus isn’t perhaps blazingly fast, but it’s pretty good; keep in mind that f/1.4 takes extreme precision and therefore the focus is slightly slower to achieve this precision. My personal major complaint about this lens (and Nikon isn’t alone) is the spherical aberration. What this means is that focus fine-tune wide open doesn’t work for the lens when the aperture is stopped down. My camera lens combination, for instance, needs +1 at f/1.4, 0 at f/2.0, and -4 when stopped down beyond that. I write this calibration information on the inside of the lens cap, since I’m terrible about remembering these rules. You can always shift to Live View with contrast-detect autofocus to avoid the focus fine-tune problem. What is needed here is a “smart lens”, such as what Sigma offers with its USB dock, that allows in-lens firmware to compensate for this focus shift. Even Sigma only compensates for distance/focal length combinations and not focus shift due to an aperture change. This spherical aberration phenomenon only seems to be an issue on high-speed lenses. If a camera could keep the aperture at the stopped-down position while focusing, then the problem would go away. An aspect of spherical aberration is “spherochromatism”, which this lens shows at wide apertures (I think all really fast lenses exhibit this to some degree). Out-of-focus objects just in front of the plane of focus are magenta and objects just behind are greenish. It’s pretty much academic in real-world use; the effect is really small and is hard to notice unless the subject is white. I briefly had another copy of the Nikkor 85mm f/1.4 AF-S. Note this is in the past tense. Its resolution measurements were generally about 11% worse (some were 26% worse). Not all lenses are made the same. Consult here if you really want to learn about lens-to-lens variation. I read a review of this same model lens here. It sounds like they might have gotten my old lens. If you want to go through the pain of evaluating your own stuff, then you need to get the MTF Mapper program and print out the resolution target files at that site. The software (at this writing) is free, and the author Frans van den Bergh is to be commended. The download site is here . I discuss using his program in another article. Since Frans tends to write for an audience at the mensa level, my article is a ‘Cliffs Notes’ version. You really should give his stuff a read, however. MTF50 Measurements I measure lens resolution at MTF50. Most published manufacturer MTF charts are at MTF10 (contrast) and MTF30 (resolution). Except for maybe Zeiss and Leica, those MTF charts are “theoretical”, meaning they’re blowing smoke you know where. The "MTF" refers to Modulation Transfer Function, which refers to how light/dark transitions happen. "MTF50" refers to the highest line frequency (line pairs per millimeter) you can have before 50% of the contrast is lost. Values above about 30 lp/mm are considered pretty good, and anything above 50 lp/mm is outstanding. I made the tests with a Nikon D7000 (APS-C sensor). If you have a quality lens like this one, then you'll get up to 26% higher resolution by switching to the 24MP sensor D7100 (I tested it). You lucky dogs with your full frame sensors will get slightly different results on the edges. What the resolution chart looks like The picture above shows what gets photographed (unsharpened, RAW) and evaluated. The program author, Frans, has a couple of chart designs, but the main idea is to align the little squares to get their edges in sagittal (spoke) or meridional (tangent) directions. The squares need a little ‘slant’ to them (5 degrees is optimal) to get measured optimally, similar to what Imatest does. Measurement algorithm problems arise if the little square orientations approach vertical or 26.565 degrees. If you try testing yourself, don’t get too sloppy about orienting the chart, and bear in mind that the squares must always be bigger than 25 pixels on an edge. The chart squares emanating from the center along 45 degrees (“X”) have MTF readings that can be 2 or 3 percent higher than they deserve. This is the tradeoff between the desire to get sagittal/meridional measurements and approaching the critical ‘bad’ slant angles. The Imatest guys have punted on this and don’t align their target squares in sagittal/meridional directions; they have 5-degree slants on all of the squares. You’ll see an “X” pattern on some of the 2D resolution plots below, due to this effect. MTF50 85mm f/1.4 wide open This is really good performance for being wide open, in my opinion. It’s just about even resolution across the APS-C sensor, too. I get to avoid any nasty dips that might lurk on those full-frame camera edges. The center of the chart at f/1.4 The MTF Mapper program provides annotations on every measured edge for every little complete square it locates in the photograph. The annotations are in units of “cycles per pixel”. These units are converted into “MTF50 line pairs per millimeter” in the plots, if the program options are configured to request that format. Nikon Official 85mm AF-S MTF ‘theoretical’ chart from their website f/1.4 MTF50 lp/mm over the whole frame This 2D view makes it easy to see how the sagittal direction brings down the averages as you get away from the lens center. The MTF Mapper program also has a 3D view option to turn those reds and greens into mountain peaks. 85mm f/1.4 worst corner for APS-C sensor The worst this lens could come up with is the top-left corner at f/1.4 reading of 28.3 lp/mm in the sagittal direction (0.13 cycles/pixel). The worst is something like 0.15 c/p or 31 lp/mm in the meridional direction. 85mm f/2.0 MTF50 85mm f/2.0 MTF50 85mm f/2.8 MTF50 85mm f/2.8 MTF50 Again, please ignore the little chart bubble defect at the top of the plot. 85mm f/4.0 MTF50 85mm f/4.0 MTF50 85mm f/5.6 MTF50 You’re getting into a rarefied atmosphere here. Due to the resolution chart individual square edge orientations along meridional/sagittal directions, it’s probably fair to knock off about 2 or 3% from the values shown for the squares that align along the main diagonals of the test chart. Even still, these readings are outrageously good. This is peak resolution performance for this lens. 85mm f/5.6 MTF50 85mm f/8.0 MTF50 Diffraction is starting to set in, so the resolution is starting to drop a bit. 85mm f/8.0 MTF50 Sample Images Bear, Sequoia at dusk. 85mm 1/500 f/2.2 ISO 640 at 30 feet. Could have used anti-shake here for my knees. Glad the termites were more appealing than me. Forest 85mm f/1.4 1/200 ISO 200 The background just melts away. This is why you buy this lens. #review

This article will show the lens MTF50 resolution performance and discuss how well the lens autofocuses. Repetition of the Nikon specifications of the lens will be mostly avoided. This is one of the most popular Nikkor DX “prime” lenses ever produced. It is also one of the most inexpensive lenses; I avoid labelling it “cheap”, since that has a connotation of “low quality”. Nearly everybody will tell you to “just get one”, and with good reason. It’s reasonably fast, focuses well, and provides the natural perspective that equates to the FX “50mm” standard lens. What you don’t get: vibration reduction and great corner resolution. My usual disclaimer: this is looking at a single copy of the lens. Yours will be different, but hopefully ‘similar’. The only place I know of that tests lots of copies of lenses is here . These tests were done using a Nikon D7100 (24 MP) with unsharpened 14-bit compressed RAW format. Here is a link to get pretty good information on this lens. My main complaint with them (and most of the other web sites) is that they simplify resolution measurement down to a single number for an f/stop. It’s not that simple; resolution is a 2-dimensional thing (not to mention directions within those 2 dimensions). The focus ring on this lens is a properly wide one, nearest the filter. Just like their ‘pro’ lenses, you can use it anytime you want to override autofocus. This ring is much better than most of Nikon’s kit lenses that have that skinny plastic thing at the end of the lens. The lens also has a proper metal lens mount and gasket (rubber seal). That’s it as far as dust/weather resistance is concerned. Annoyingly, there is no distance scale. Not a huge problem, but still it should have one. Also note: don’t use this lens for infrared; it produces a nasty hot spot in the middle of the field of view in infrared; Nikon’s (even less expensive) 50mm f/1.8 AF-D lens in comparison is wonderful when shooting infrared, and it also is an FX lens. As an aside, Nikon’s 18-55 various kit lenses are all very good at infrared. Nikkor 35mm f/1.8 DX AF-S with included hood Autofocus Fast, repeatable, silent. Enough said. All of my lenses need some focus fine-tune calibration; so does this lens. Vibration Reduction (VR) Nope. Helps keep this lens inexpensive. Even Nikon’s 85mm f/1.4 AF-S doesn’t have VR. Just saying. Resolution Testing This is why you should read this article. I won’t mention “good”, “fair”, “excellent” or “blur units” to interpret resolution. I promise. My goal is to enable you to evaluate resolution between lenses in a standard, scientific way. I also give you the information (see my MTF Cliff’s Notes article) to be able to repeat these tests for yourself. Resolution measurements are in MTF50 lp/mm. This measurement represents how many image line pairs can fit inside a millimeter before the white-to-black chart transitions degrade to 50%; e.g. “turn to mush”. For me, anything beyond about 30 lp/mm is fine, and beyond 50 is outstanding. Higher-resolution sensors yield higher measurements, much like you’d expect. Before I forget, you will notice a couple of tiny weird blobs in some of the resolution plots that follow (along the top edge). Please ignore these, since they are definitely not a lens imperfection. The measurement software is extremely sensitive, and an imperceptible chart surface indentation shows up very clearly in the measurements. I guess I’ve been doing too many tests and will soon have to retire this chart. I use a (free!) program called MTF Mapper from here to measure lens resolution. The download site also has files for printing out the resolution targets (mine are A0 size on heavy glossy paper (‘satin’ finish seems to work just as well), dry-mounted onto a board). This program is covered in more detail in another article, but suffice it to say that this is really great stuff; it’s comparable to ‘Imatest’ in the quality of the MTF measurements, and it uses the “slanted edge” technology similar to ‘Imatest’, also. The author of MTF Mapper, Frans van den Bergh, really knows his stuff. Visit his site and give him the praise he deserves. The chart design used for resolution tests orients all of the little black squares to be ‘slanted’ but they’re generally aligned in meridional and sagittal (think spokes on a wheel) directions to correlate better with the usual MTF plots you’re familiar with. There’s often a dramatic difference in sharpness between these two directions, and the chart photographs show it clearly. The meridional/sagittal differences are what “astigmatism” is all about. This lens is decent in the sagittal direction when you get away from the lens optical center, and corners are “okay”. Meridional direction is a less rosy proposition, but judge for yourself in the ensuing resolution plots. The middle of the lens is impressive, as you’ll see. What the resolution target looks like. Mine is mounted ‘upside down’. At long last, I’m getting around to some actual resolution results. Tests were done with “Live View” AF-S autofocus, contrast detect, IR remote, VR OFF, really big tripod. That’s how I get around any phase-detect problems with focus calibration. The results don’t seem to improve using manual focus and 100% magnification in Live View, so I don’t bother. I use the “best of 10 shots”; not every shot gets the same resolution results. All cameras operate on the “close enough” principle for focus, so many tests are needed to determine the best resolution that the lens can produce. Small resolution chart imperfection on top edge; please ignore. Diffraction is exacting its toll at f/16. Sample Pictures Pumpkins that look amazingly like a tiger Panorama from 5 vertical-format shots stitched using the Hugin program #review