Ed Dozier

Sep 4, 2015

Sigma 150-600 f/5-6.3 DG OS HSM C 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.