This review will primarily detail the lens MTF50 resolution performance and how well the lens autofocuses. Other reviews already rehash the Nikon specifications of the lens, so I don’t intend to repeat all of that here. I don’t sweat minor lateral chromatic aberration, noticeable distortion, and vignette issues; software fixes those. Software can’t create missing resolution, solve inaccurate focus, or rid focus chatter. I should mention that vignetting at 140mm is breathtaking, but lucky us that software rids it with virtually the click of a button. 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 D7000 (16 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 try to reduce resolution measurement down to a single number for an f/stop and focal length setting. It’s not that simple; resolution is a 2-dimensional thing (and also a sagittal versus meridional thing). Here’s another gripe: Nikon doesn’t even include a lens hood or lens pouch. That’s really insulting, considering the price of this lens. This lens telescopes out into three sections as you zoom. The tolerances are really tight, though, and it doesn’t have any “wiggle” in it. Everything feels surprisingly solid with this lens. Don’t drop it, though (as if ANY lens handles dropping well). As opposed to most of their “kit” lenses, the focus ring on this lens is a proper one, nearest the camera. It’s sufficiently wide that I have no complaints about it. Just like their ‘pro’ lenses, you can use it anytime you want to override autofocus. The lens also has a proper metal lens mount and gasket (rubber seal). That’s it as far as dust/weather resistance is concerned. If you damage any Nikon lens with water or dust, including weather-sealed lenses, your warranty plus 5 bucks entitles you to a latte. Nikkor 18-140mm zoomed out to 140mm Autofocus Focus was a bit sluggish on my D7000 in dim light, and quite a bit faster on my D7100. Since this isn’t exactly a sports/wildlife lens, that’s a minor point. Focus is very repeatable, and that is what’s important. There was zero focus chatter, and that’s crucial (lenses that have focus chatter are useless, in my opinion). If you’re too far out of focus, you will probably need to give it a nudge in the right direction using the manual focus ring. This is really common for lenses. I may be pickier than many on this point, but I did notice a focus calibration shift at different focal lengths. It’s not huge (about 4 fine-tune units), but I’d have to say that it’s my least favorite thing about this lens. Stopping down about one stop will mask it. I really wish that Nikon would “invent” a docking station like Sigma has, so you could customize focus tuning at different focal lengths and distances; oh, well. 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. Vibration Reduction (VR) This seems to be the most capable lens VR I have yet tried, at about 4 stops. Everybody is different in how they support the camera while hand-holding it, so your mileage will vary here. I determine “sharp” versus “un-sharp” by photographing a resolution chart at slow shutter speeds and measure where the resolution (MTF50 lp/mm) drops by 10% from maximum. I don’t know if there is some industry standard on VR effectiveness, but what counts for me is when pictures just start to show some blur, and I like to do it by the numbers. I haven’t figured out how to calibrate my level of nervousness with hand-holding, so this VR business is literally “hand waving”. Oh, also, I test at the longest focal length. Resolution Testing Here’s where I get to rant about those lens reviewers that grade lens resolution with adjectives like “good”, “fair”, and “excellent”. What the heck does that mean? How about 2 ‘blur’ units??? Really? 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. 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 honestly really bad in the meridional direction. Corners are decent from 18-50mm, but then performance goes south (astigmatism galore). But the middle of the lens, at all focal lengths, is really, really good. In fact, it mostly makes up for the corner performance. 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. 140mm f/5.6 APS-C Corner. Note Sagittal is MUCH better than Meridional 18mm center wide open is quite amazing. Even corners are pretty good. I got 38mm with 35mm mark on lens. Big resolution dip from 18mm. 50mm about the same as 35mm resolution 70mm wide open. Meridional-direction corners aren't looking too good. 140mm wide open. Again, weak corners but great in the center Samples 18mm. You really notice the barrel distortion. 18mm with software lens distortion fix. Voila, you can ignore distortion. Used Capture NX2. Southern Cal. Christmas Tree. 140mm. Near closest focus (1.55 feet versus 1.48 feet closest focus) at 140mm, 1/160, f/7.1, VR ON #review

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

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

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

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

Flash FP Mode This article discusses the Nikon FP flash mode, which is often derided by photographers as ‘beneath contempt’. That’s not my opinion. What is it? FP mode causes your (external) flash to emit a bunch of rapid light bursts instead of one big one. These rapid bursts keep the xenon in your flash continuously energized, so the light output stays at an almost-constant level. The upside to this is that you can use a shutter speed like 1/4000 and still use flash. BTW, “FP” is short for “focal plane”, and is perfectly descriptive to nobody outside of Sendai Japan. Think “flash bulb” for those of you born during the Pleistocene epoch. What is it good for? FP mode enables you to use high shutter speeds in conjunction with your flash, so you can do things like fill in shadows outdoors in sunlight. You can fill in those terrible dark blobs under the eyes and nose, and you can get that sparkle back in the eyes. You can use those large apertures you paid for while outdoors, and still get fill-in flash. FP mode isn’t something you would want indoors; regular flash mode will work better there. It’s really just available so you can get beyond the “sync speed” of the shutter while outside. It's true that you can use something like "D-Lighting" while postprocessing the picture to fill in those shadows, but this is really second-best to getting it right in the beginning. You don't want to add shadow noise when there's any easy (better) option. If you're too far away from your subject you may have no choice, but your flash can have a positive effect from farther away than you might think. There is still no such thing as a free lunch. The light output from your flash will be less (about 2 1/3 stops). And you have to stick that flash on top of your camera. I suppose you could rig up a “light tube” around your flash to project a narrow beam when you use that telephoto and regain some of those lost stops. It’s possible to use “commander mode” with your camera internal flash to invoke FP mode, but it gets too complicated. How do I get it? You have to set “Auto FP” mode in your (Nikon) camera. I’m clueless if Canon has it. You need a separate Nikon flash (I use the Nikon SB600, but the 700,800,900 series have it too). When you set a shutter speed faster than your internal flash can handle (like faster than 1/250), the external flash enters the FP mode. If you’re inside, you can just change the shutter speed to the flash sync speed or lower and the flash will automatically exit FP mode and act like a regular flash. Manual mode A related topic is using your camera in ‘manual’ mode with a flash. Guess what? Your flash is still in ‘automatic exposure’ mode, even when your camera is in ‘manual’! Is that great or what? A nice effect to try is to under-expose in manual mode by about 1 ½ stops and let your flash do the rest. The flash will expose your subject correctly (if you’re close enough), but the background will be nicely under-exposed by just the right amount. Indoor shots are somewhat disturbing when the background goes black, and it screams ‘amateur’; use manual mode to get the ambient light levels up, and the flash can correctly light your subject. Nearly every picture is improved when you use fill lighting. Jacking up the ISO isn’t always the best solution to low light, either. #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

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

This document was created to explain in simpler terms how the mtf_mapper_gui.exe program works. The program has two main purposes, (1) to aid camera focus calibration (2) lens resolution measurement. This program and other programs offered at the link below actually do a lot more, but this is what most photographers are interested in. The MTF Mapper program author is Frans van den Bergh. His software and printable test charts are available here: Frans comes across as a scientist-type guy, and his documents can sort of take your breath away. They’re worth a read, though, even if you can’t grok 100% of their contents. More of his writings about image analysis topics can be found here If you like his stuff as much as I do, please let him know! MTF Mapper uses a program called “dcraw” (included in download) that knows most “raw” formats, and is regularly updated for new cameras. 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. Resolution Measurement To start out, here’s some typical “Profile” output from his program: Resolution profile plot. Lens MTF50 is about 50 lp/mm To make a profile plot, there are a couple of things that need to be done first: Print out a test chart; print it big, mount it flat, use good heavyweight glossy paper. A0 (about 33” X 47”) is great. "Satin" finish papers work well, too. You may need to change the MTF site test chart file formats from ".svg" (scalable vector graphics) into something your program likes better, such as ".pdf". There is freeware that can do this. Make sure you stick with “raw” mode with your camera, and don’t sharpen the pictures. Photograph the chart (‘contrast detect’, live view mode is recommended) in diffused light. I find that a "+1.0" exposure compensation works best to keep the white background light. Run mtf_mapper_gui.exe File | Open… then pick the picture(s) to analyze Click on “profile” on the right-hand side after the picture analysis finishes. You don’t have to wait for the other pictures to get analyzed. Resolution chart with ‘slanted squares’ provided by Frans The resolution chart has little slanted squares that mostly look like spokes branching out from the chart center. The measurement algorithms work best with edges that have a slant around 5 degrees. The “spoke” structure is ideal to get measurements that can be separated into the sagittal and meridional directions, like most MTF plots are. Unfortunately, the spokes nearest a 45-degree “X” pattern get slightly higher measurements than they should (a few percent higher). For most people, this is a “don’t care”. See below for more information on this, if you’re the “care” type. “MTF50” is a pretty stringent measurement. Most manufacturers give you MTF10 (contrast measure) and MTF30 (sharpness measure). Annotated picture up close The ‘annotated’ picture above shows a zoomed-in view of the measurements for each whole square the program could locate. Good measurements are in green. Marginal measurements are in blue (typically within a degree of 0, 26.565, or 90 degrees). Bad measurements are in yellow. If squares are too small (less than 25 pixels per edge) you get a bad measurement. You don’t have to photograph the whole chart; it finds and measures only whole squares. The chart doesn’t have to fill the viewfinder, but don’t let the chart squares get too small (less than 25 pixels). You’ll probably want to add more exposure than your camera meter indicates; you want a light background with the black squares. If the meridional measurement on a square is different from the sagittal measurement, you have astigmatism. You’ll probably notice that the sides of the squares parallel to each other have measurements that nearly match each other. Don’t get too sloppy here. Bad chart rotation can spoil readings. Diffuse light works better than ‘hard’ light. Use a tripod, remote shutter release or self-timer, and mirror-lockup to avoid vibrations. Bump up ISO if you need to for higher shutter speeds, since higher ISO speeds doesn’t mess up the results nearly as much as blur does. I equate the direction “sagittal” to “spoke”, like spokes on a wheel. The term “meridional” is sometimes called “tangent”, and it’s perpendicular to the “sagittal” direction. Note that different resolution camera sensors will give different MTF50 results; this is normal. Remember to set the "pixel size" in the program 'Preferences' to the correct pixel size! How to convert “cycles per pixel” into other measurements Assume the camera sensor is 3264 X 4928 pixels, or about 15.7mm X 23.6mm. Assume an edge measures 0.27 cycles per pixel. MTF50 lp/mm = cycles_per_pixel * height_pixels / height_mm MTF50 lp/mm = 0.27 * 3264 / 15.7 = 56 lp/mm Line pairs per picture height = Lp/ph = lp/mm * height_mm Lp/ph = 56 * 15.7 = 879 Customize the way mtf_mapper_gui works In Settings | Preferences check the “Line pairs/mm units” if you want these units in the “profile” plot. Verify your camera’s pixel size (microns) in the same Preferences dialog. The Nikon D7000, for instance, has a pixel size of 4.78 microns. A D7100 camera is 3.92 micron pixel size. 2-D Grid Plot of Entire Resolution Chart (D7000) Select the “grid2d” to see the resolution measurements throughout the sensor. The pair of plots separate out Meridional and Sagittal readings. This shows that meridional results are better than sagittal results at this f-stop. I like this chart the best of all the available outputs, since it gives a complete picture of the sensor performance, and it separates the readings to get the best understanding of astigmatism (when sagittal/meridional values are different). There’s a “grid3d” plot if you want it, which is basically taking a 2D plot and viewing it at an angle to get the third dimension. Weird “X” Pattern If you ever notice a sort of “X” pattern that fills most of the 2D plot, but only has a difference range of a few percent, it’s an artifact of the square shape of the camera sensor photo sites (its pixels). Frans has an article about this at the download website. Don’t freak out; your lens doesn’t have some kind of cloverleaf inside it. The “green” sagittal cloverleaf readings above are reading slightly better than they really are; the ’52’ scores are probably nearer to ‘50’. If the chart squares were all locked at a 5-degree tilt, the effect would go away, but then you don’t get to see the sagittal/meridional separation. This is the tradeoff being made. The “Imatest” guys opted for the “only 5-degree squares” and sacrificed providing sagittal/meridional data. Frans says he might someday provide both kinds of charts, so you get to choose which you like better. Focus Calibration Focus Chart provided by Frans showing where to focus For focus tests, print out the focus chart and mount it flat. Photograph it while it’s slanted 45 degrees from your camera, with the left-edge (above) of the chart farthest away from you. There are a few charts to choose from; choose the chart that best matches your lens focal length so that the picture looks most like a rectangle instead of a trapezoid. Only use your “phase detect” autofocus setting (not contrast detect live view) to focus the chart, since the point of this test is to test the phase detect system. Use fairly bright light (typically EV10 or better) to make sure your camera doesn’t have to hunt for focus. Use your center focus sensor, and aim it as shown above in red. Plot of focus chart photo The above results show a slight focus error. The camera focus fine-tune (or the lens fine-tune if it’s a new Sigma lens) will need a (-) adjustment to pull the focus nearer to the camera. You might find it easier to determine the focus error by looking at the "annotated" picture values instead of relying upon the "profile" image. Take several shots before you decide how much to change the focus calibration. Each test will probably be a little different. Photo of Chart. Notice the annotated squares added by mtf_mapper_gui.exe The focus sensor was trained on the center of the big rectangle (trapezoid, actually) vertical right edge. Chart was mounted at 45 degrees, with the left side of the chart farther from the camera. #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 review is mostly concerned with the lens MTF50 resolution performance and how well the lens autofocuses. I’m not overly concerned with minor lateral chromatic aberration (since the software fixes it), trivial distortion (software can fix it), and some vignette issues for full-frame users (software can fix it, too). What software can’t fix is a lens that focuses poorly or has weak resolution. The Sigma 150-600 Contemporary lens delivers where it counts. All across the field of view. And it delivers with the aperture wide open (which is pretty much where I park it). This is a “single lens copy” test, so your mileage may vary. I know, you’re suspicious that the Contemporary resolution is garbage compared to the Sports version; read on. I’ve spent the better part of my life wanting a really big lens that wasn’t crap or cost as much as a car. Here it is. It’s liberating to frame a subject the way I want, and actually have some elbow room in focal length left over. For those of you that want to shoot eagles in a dive with a 600mm prime lens, good luck finding it looking through an 11-pound straw. You want a zoom to find the thing and then zoom in. This is among the smartest lenses on the planet to date. Don’t get this lens without the Sigma USB dock and its Optimization Pro program; you’ll regret it if you do. The dock will let you properly calibrate focus at 16 combinations of focal length and distance; all zooms need this capability, but all of the other manufacturers have done nothing about it to date. If you read a review mentioning something like "it focuses well at 40 feet but not infinity" then that probably means that they didn't bother to carefully calibrate the lens at each focal length and distance setting using the Sigma USB dock. Don't be lazy! I hope you’re ready for a 4 1/2-pound lens, though (with hood). I can’t imagine hauling around the ‘Sports’ version all day, which is about 7 pounds (with hood). You might try renting a beast like the Sports version and carry it for a whole day before you buy it. Maybe you shoot in rain and dust all the time and need the Sports version; it’s a heavy price to pay, though. Sorry about the pun. I mostly bring a monopod with a gimbal head and an Arca-Swiss plate when shooting animals. You can shoot all day, properly balance the lens at every focal length, and most importantly not suffer while trying to hold this thing steady. I have lasted maybe an hour with the lens hand-held before I was ready to call it quits. I typically use the “OS2” stabilization setting (panning) instead of “OS1” (general hand-held) in poor lighting on a monopod. If I move the lens both vertically and horizontally, though, then I need "OS1" set (until about 1/1000 second, beyond which it should be turned off). The lens center of gravity shifts quite a bit while zooming, hence the Arca-Swiss plate. 3-17-2017 Update After the firmware update from Sigma (using the optional USB dock) you no longer need to turn off optical stabilization when using high shutter speeds. Yes, you’ll need to stop using ISO 100 with this lens. Get over it. Even the people shooting with the $10K+ super telephotos have gotten over it. Learn to love f/6.3. Here’s a word or two about “plastic”. Some of the finest and most high-tech materials in the world are plastic. They didn’t make this lens out of melted milk jugs. They use thermally stable composite; it’s tough and has excellent dimensional properties, even over a wide range of temperatures. And it makes the lens light enough that you can actually walk around with it. I used to be jealous of those guys with the little wheels on their tripods and their 400mm f/2.8, 10 pound lenses. Careful what you wish for. Just don’t drop the lens. Same goes with metal lenses; drop a big lens on the sidewalk and it’s a goner, period. I don’t see too many plastic football helmets breaking, and I don’t see too many “quality metal” football helmets, either. Sigma gives you a neck strap that attaches to the tripod collar. It might seem a little geeky, but it is a great insurance policy. I use it, especially when I’m adjusting the monopod leg when it’s attached. And never, ever hold this rig by the camera; bad things will happen. I also use a Cotton Carrier to carry the lens on a waist belt when I’m not going to be shooting for a while; it totally saves your back and neck. The lens comes with a zoom lock, so it won’t creep out to 600mm while you’re walking with the lens pointed down on the waist belt; it doesn’t creep getting a moon shot over head if you lock it, either. Nice. The lens hood is bayonet, which is always my favorite. It reverse-mounts for storage, which is exactly what you want. The lens is breathtakingly long at 600mm with the hood on, but what did you expect? You always want to use the lens hood; the longer the focal length, the more important it is to use the hood. Lots of glass in that lens. You also get a pretty nice storage case with the lens. I swear that the Sigma designers must actually use their lenses. What a concept. You have to wonder about some of the other manufacturers. One note about the zooming. It’s Canon-standard direction and opposite the Nikon-standard. Not much of a problem when you’re sticking with one lens, but muscle memory goes haywire when using another lens on the same day. Sigma even offers a service to change the lens mount if you have a mid-life crisis and switch from Canon to Nikon or whatever. It’s my understanding that Canon and Nikon do not offer this service. Duh. Sigma 150-600 Contemporary at 600mm on gimbal head Lens was elevated a little higher than ideal in the gimbal so you can see it better. Properly balanced using Arca-Swiss plate. Note the supplied neck strap Autofocus I prefer to use the camera in AF-C mode and a separate focus button. This lens focuses quickly with absolutely no chatter using the factory default AF algorithm. Lenses with focus chatter (like my Nikkor 70-300 AF-S) drive me crazy, especially with their auto-50%-un-sharp-rate. Three different autofocus algorithms are available with the Sigma Optimization Pro and USB dock. Choose between Speed Priority, Standard (factory), or Accuracy. I wasn’t happy with the repeatability of Speed Priority, and the factory setting works very well for me. I’m leaving this customization alone and sticking with the factory setting. I have, as a matter of fact, assigned “C1” to be Speed Priority and “C2” is Accuracy, but I am presently leaving this custom switch OFF, to get the factory default Standard setting. Sigma is bound to optimize their autofocus algorithms more in the future, so I may re-evaluate my decision to avoid using Speed Priority. You’ll probably want to use the “Focus Limiter” switch to get a more substantial speed-up of autofocus without sacrificing accuracy or repeatability. Just don’t forget when you decide to limit the focus range. I’ve missed several shots when a subject moved just outside the range setting. Update 3/21/2016 Sigma released new firmware that makes focus between 20% and 50% faster. I told you so. Sigma did it for FREE, too. The USB dock just paid for itself yet again. I tried it out, and the focus really snaps. My test shots (not new resolution test charts, though) don't show any obvious loss in sharpness with this speed increase. I found the focus motor to be remarkably quiet. Always a good thing. I focus-calibrate the lens and use the Sigma USB dock to save the data before I do any resolution testing. Tests are done with stabilization off, contrast-detect autofocus (mostly), and I use the infrared remote with the mirror up. I only use RAW, unsharpened pictures for measurements. Testing was done using a Nikon D7000. I have been amazed how close phase detect focus compares to contrast detect focus with this lens. Newer cameras will only be better. Sigma dock 16 focus calibration settings. Your settings will be different. It’s a ton of work to fill in the 16 calibration settings with verified values; there were iterations galore. You’ll thank yourself once it’s done, though; no pain no gain. Maybe some day Sigma can write these values for us at the factory, since they claim to measure every lens MTF anyway for quality control (I bet they don’t do it at all 16 combinations, though). Note that the “Rewriting” button above needs to say “Save”. I wonder how well I would do if I had to label the buttons in Japanese. Focus Limiter Range You can tailor the distance ranges applied to the Focus Limit switch using the USB dock. You probably don’t want to alter the “Full” range setting (minimum focus to infinity), but that’s just me. You might want to change the “10m-infinity” setting to actually use something like “5m-infinity”, though. The focus limit switch settings on long focal lengths can be pure gold for minimizing the time to acquire focus. I’d try this feature first before I’d look at the “Speed Priority” autofocus algorithm. Don’t take my word for it, though; try it for yourself. OS Setting (Vibration Reduction) Customization It claims to alter the amount of visible vibration reduction in the viewfinder (as opposed to actual sensor anti-shake). It presumably provides the same level of anti-shake effect in the actual photographs, regardless of the setting. Honestly I haven’t experimented with this, and the factory setting works well (but the subject does move around more in the viewfinder than I’m accustomed to seeing with Nikon VR in effect). Remember to always turn off the OS when shutter speeds go faster than 1/500 (or at least 1/1000). Do as I say, not as I do. The programmable settings are referred to as “Dynamic View”, “Standard”, and “Moderate View”. I’m personally able to get about 3 stops of shake reduction with the factory setting. Since I mostly use a monopod with this lens, I use the OS-2 (‘panning’) versus the OS-1 (‘normal’) mode in poor light. If I have any vertical motion, however, then the best setting is OS-1. Most reports suggest that the OS provides about 3 2/3 stops enhancement. I guess I shouldn’t have had that last cup of coffee before I tried this. I have found that the shutter range between 1/500 and 1/1000 is 'murky'. Generally I have better results with stabilization ON here; beyond 1/1000 shutter, active OS makes resolution drop about 9%. 3-17-2017 Update: The firmware update fixes the problem with using stabilization and high shutter speeds. It also increased focus speed. "Moderate View" gives the best stabilization effect, although "Dynamic View" provides the smoothest viewfinder effect. See my article here. I was correct about improvements in future firmware updates! This feature (finder view and sensor anti-shake) is likely to get improved in future firmware updates, since stabilization is a mix of both lens hardware and firmware algorithm cleverness. Resolution Testing I hate those lens reviews which grade lens resolution with adjectives like “good”, “fair”, and “excellent”. What the heck does that mean? I want real numbers and I want to see real pictures of things I’d actually bother to photograph. I want to see sharp eyes, fur, and feathers. Does the camera sensor matter? Yes! Tests shown below on a Nikon D7000 can be improved by about 20% by switching to the Nikon D7100, for instance (I tested it). 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, mounted on 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. The MTF Mapper documentation he wrote works best for people with an IQ around 180 and above, I suspect. 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. You can judge for yourself how the sample photos in this article relate to the MTF50 numbers I measured. Always keep in mind that this is just ONE lens sample; I guarantee your mileage will vary. Some physics facts first. The 600mm resolution isn’t going to be as good as 150mm, even if the optics are “just as good”. Vibrations are magnified and the extra atmosphere between the lens and the subject will cause a little shimmer. Just saying. 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 better in the sagittal than the meridional direction when you get away from the lens optical center. BTW, there is a mild “X” pattern that shows up in many of the 2-D focus plots; Frans van den Bergh has shown this to be a consequence of the square shape of the photo sites on the camera sensor itself. The MTF50 values are only very slightly affected by this (about 2% error along the “X”). You can get a load of how smart Frans is by reading his discussion of this phenomenon here. You might want to grab a cup of Joe first. If you think that the resolution test values should match the manufacturer MTF plots, think again. You might want to consult Roger Cicala’s article here to get a rude awakening. BTW, Roger uses “tangential” instead of meridional terminology. What the resolution target looks like. You’re probably wondering by now if I’m ever going to get around to some actual resolution results. I am, but I just wanted to provide some background into why the resolution results have actual validity (for this particular copy of this lens model). I hate “secret science” and hand-waving claims. I guess it’s just the engineer in me (I’m a mechanical engineer and software developer). I want you to be able to do the same tests as me. Thanks again, Frans. 600mm f/6.3 Note peaks at almost 40 lp/mm Note the little red edge measurements in the plot. The sagittal measurements are quite a bit better than the meridional (tangent) measurements. Note the EXIF data shows this was shot at about 62 feet (18.8m). This is a pretty realistic distance for a focal length like this. Farther than most testers would attempt. Tests were done in “Live View”, contrast detect, IR remote. The 600mm f/6.3 test above was 1/640s, ISO 800, +0.7EV exposure compensation, lens vibration reduction OFF. This is approximately EV 12.3. All subsequent tests were ISO 800 to maintain high shutter speeds. Resolution on this camera drops off after about ISO 1600. 600mm f/6.3 whole field of view. Sagittal is better than Meridional 600mm f/8 resolution not much different 600mm f/6.3 Lens Center I know, I know. There’s a little crease in your chart! Fortunately, it didn’t have any effect on the measurements. 600mm f/6.3 APS-C Corner. Note Sagittal much better than Meridional 500mm wide open 500mm wide open 500mm f/8.0 500mm f/8.0 400mm f/6.0 A bit of a surprise seeing this much astigmatism here (look at the wide vertical spread on those data points). Nonetheless, pictures at this focal length look pretty nice to my eye. 400mm f/6.0 whole sensor 2D view It’s the meridional measurements on the sensor edges are bringing down the averages. The center is really, really sharp. 400mm f/8 400mm f/8 300mm wide open. Pretty awesome. 300mm f/5.6 Flirting with 50 The test chart A0 size wasn’t quite large enough to fill the frame at this distance. 300mm f/8. That’s what I’m talking about 300mm f/8 200mm wide open Note the distance change for 200mm and below. The chart is back to filling the frame. 200mm wide open 200mm f/8. Look at all those red specks over 50 200mm f/8 150mm wide open 150mm wide open 150mm f/8 awesomeness It’s a crying shame that I almost never use 150mm (except to locate the target before zooming in). I bet it would make stunning portraits, but depth of focus might be a bit too deep for my taste. 150mm f/8 Sample Pictures Cheetah Deep Shade 500mm f/6.0 1/250 ISO 2000 stabilization OFF Cheetah crop to see eye detail. Enough said. Grizzly 240mm f/5.6 1/200 ISO 1250 stabilization ON Hummer 480mm f/6.0 1/800 ISO 1000 stabilization OFF Lioness 440mm f/6.0 1/500 ISO 1600 stabilization ON Lion 600mm f/6.3 1/1000 ISO 1600 stabilization OFF. Nice background blur #review