Sigma 100-400mm f/5-6.3 DG OS HSM C Lens Review

Sigma has a long history of designing and manufacturing long focal length telephoto zoom lenses, so we should not be surprised to see this one hit the streets. However, this lens is likely to garner more attention than many of the predecessors. The 100-400mm f/5-6.3 DG OS HSM Contemporary Lens is Sigma's first "Global Vision" entry featuring this approximate focal length range and most of the GV lenses have been well received. That this lens is easily the smallest and lightest in its class warrants attention and that it is very-low-priced raises eyebrows. With great image quality from a feature-filled package, this lens warrants kit-addition consideration.

Focal Length Range

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Getting the right focal length range is a critical part of the lens selection process and once again, the focal length range made available by this lens is a compelling feature. This medium-to-long telephoto focal length range has a great number of uses and is ideal for general purpose telephoto needs.

Wildlife photography is one of the best uses for the 100-400mm focal length range. As the "wild" in wildlife hints to, it is often not easy to get close to wild subjects that can run/hop/leap/crawl away. These subjects can be found right in the backyard.

The cottontail rabbit above was photographed handheld at 400mm f/6.3 on a full frame camera just outside of the house.

A few days later, my wife informed me that there was a garter snake in front of our house. I asked if it was in a tree and she replied that it was on the ground. I figured that I had spent an hour photographing the same subject a few days prior and shouldn't spend the time capturing a same-species snake in a less-intriguing environment.

I can't remember the reason why, but I went outside not long afterwards and ... there was the snake she told me about. It was neatly wrapped up in an interesting position and I couldn't help myself. The snake had to be photographed.

The long focal lengths available in this lens allowed me to capture some images from a non-scary distance. To clarify: I was not afraid of the snake, but the opposite was not true. I was able to set up a tripod and frame the snake relatively tightly at 345mm (f/11), leaving some focal length still available while giving the snake enough room to be comfortable with my presence.

Especially at 400mm, this lens can capture even skitish wild critters nicely large in the frame from a not-terribly-threatening-to-the-animal distance. Or, there are some subjects that you may not want to get closer to and this focal length range is there for you in that regard.

Another good reason to use medium and long telephoto focal lengths is for the compressed perspective the narrow angle of view invites. And, landscape photography is an excellent opportunity to use this technique. It is no secret that landscapes are one of my favorite subjects and ... I got distracted at this point in the review.

I looked out the studio windows to see some beautiful clouds (one of my weaknesses) and I saw a great opportunity to put the Sigma 100-400mm OS lens into use. I mounted a circular polarizer filter and went outside.

Yes, that appears to be a mushroom cloud, but no, the local town was not attacked. Can you see clouds from where you live or from places you visit? Clouds can be incredibly beautiful and ever-changing, meaning that you can always be photographing something different and likely different from what someone else has photographed. Even at 220mm, it doesn't matter what the landscape looks like because the image can be just clouds.

With a unique weather pattern moving through, including many small rain storms, I decided to take the Sigma 100-400mm f/5-6.3 DG OS HSM C Lens mounted to a Canon EOS 5Ds R along with a wide angle lens for a trail run. Yes, now I am distracted and I'll take you along for the tangent as it helps to illustrate the value of this focal length range. My distraction was worth it and hopefully this tangent will help you see the value in having this focal length range available in your kit.

At about 1 mile (1.6 km) out and at a high elevation, I could see small storms moving through and was photographing them with sunbeams shining through them. Then this little storm came directly at me.

I photographed the storm until I began to get rained on. Small storms with sun behind them forecast something that everyone loves, so I put the camera and lens back into the small Think Tank Photo StreetWalker backpack and ran about 1/4 mile (.4 km) through the woods to a view overlooking some fields where I predicted the special subject should become visible and .... bammm! There it was.

The same weather pattern provides for dramatic skies at sunset and I of course stayed for that event. Long focal lengths are great for making colorful sky photos from even modestly nice sunrises and sunsets. I'll restrain myself from sharing more of the images from that evening, but a couple of hours with the Sigma 100-400mm C netted me a quite-significant number of images I liked.

Whether the reason you cannot get closer is motivated by a safety concern (from or for the subject) or just because there is a physical barrier to getting closer, this might be the right focal length range to have mounted on the camera. The sideline of a sports field qualifies for the latter and sports photography is another pursuit that begs for telephoto focal lengths. While 400mm may still feel short in front of a full frame camera when photographing deep into large-field events, in front of an APS-C model where it provides an angle of view equivalent to a 160-640mm lens on a full frame camera, 100-400mm can cover a significant portion of even large soccer, football, field hockey, lacrosse, etc. fields.

Often prime lenses are used for telephoto needs, but the advantages of being able to zoom out to wider angles (129mm in this case) has great benefits. With a zoom range, it is possible to move in front of obstructions (tree limbs for example) and zoom out while still maintaining the ideal framing in a wide range of situations. Also, less cropping may be required due to the ideal framing being quickly selectable via the zoom ring. Taking up a position that provides focal length headroom for the subject allows the ideal composition to be adjusted just-prior to capture, resulting in higher resolution results compared to cropped alternatives.

Sometimes, laziness is a good reason to use the 100-400mm focal length range. Sit in the comfort of your car, avoid the need to cross a creek, stay back from the surf, etc.

While wildlife, sports and landscape photographers will make up large percentage of the owners of this lens, there are plenty of other uses for this wide 4x focal length range. This zoom range is a great choice for chasing the kids outdoors such as at the park or at the beach. Photojournalists with restricted access to their subjects may find this focal length range useful. Portraits, especially the tightly framed variety, are on this lens's to-do list. This focal length range will be nice for zoo photography and for airshows.

Here is an example of what this focal length range looks like:

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Here is an example of what this focal length range looks like on an APS-C format DSLR (borrowed from the Canon EF 100-400mm f/4.5-5.6L IS II USM Lens Review).

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In summary, the 100-400mm focal length range can be found useful by most and it can be highly rewarding to have such a lens in the kit.

Max Aperture

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Because aperture is measured as a ratio of lens opening to focal length and because this lens maximum opening does not increase enough with focal length increase to maintain the same ratio, the max aperture is a variable one, ranging from f/5 to f/6.3 as the focal length range is traversed.

As always, the lower the aperture number, the more light the lens will allow to reach the sensor. Each "stop" in aperture change (examples: f/2.8, f/4.0, f/5.6, f/8, f/11) increases or reduces the amount of light reaching the sensor by a factor of 2x (a big deal). Allowing more light to reach the sensor permits freezing action and handholding the camera in lower light levels and can also permit use of a lower (less noisy) ISO setting. In addition to allowing more light to reach the sensor, increasing the aperture opening permits a stronger, better subject-isolating background blur (at equivalent focal lengths). Also, lenses with an opening wider than a specific aperture (often f/2.8) enable the higher precision AF capabilities (most often the center AF point) in some cameras and present a brighter viewfinder image.

The advantages of a narrow aperture, because the lens elements can be reduced significantly in size, include lighter weight and lower cost. Those are two factors that we all can appreciate and these principles are hard at work here. The variable max aperture has the same two advantages, compounding the benefit. A downside to the variable max aperture is that, by definition, the widest available f/5 max aperture cannot be used over the entire focal length range. Your camera will automatically account for the change in auto exposure modes, but making use of the widest-available aperture in manual exposure mode is complicated somewhat.

The bottom line is that this lens has a relatively narrow aperture at the widest focal length and by 234mm, it has the narrowest max aperture found with any frequency in any modern camera lens. In fact, it is 1/3 stop narrower than many cameras require for autofocus to function (f/5.6). Apparently, there is some leniency in this spec as, fortunately, these cameras will autofocus this lens.

This lens is not an ideal choice for stopping low light action. When the sun goes down, action sports photographers using this lens (or similar models) will be reaching for high (noisy) ISO settings to keep images bright enough with the short shutter speeds needed to freeze their subjects' motion. This lens is not a good choice for indoor sports or for anything else that moves in low light.

It is normal for long focal length zoom lenses to have a variable max aperture and the Sigma 100-400 Contemporary Lens is one of the darkest lenses available – though the difference from its nearest competitors is not dramatic.

Model	f/4.0	f/4.5	f/5.0	f/5.6	f/6.3
Canon EF-S 55-250mm f/4-5.6 IS STM Lens	55-63mm	64-99mm	100-154mm	155-250mm
Canon EF 70-300mm f/4-5.6L IS USM Lens	70-103mm	104-154mm	155-228mm	229-300mm
Canon EF 70-300mm f/4-5.6 IS USM Lens	70-84mm	85-134mm	135-224mm	225-300mm
Canon EF 100-400mm f/4.5-5.6L IS II USM Lens		100-134mm	135-311mm	312-400mm
Nikon 80-400mm f/4.5-5.6G AF-S VR Lens		80-134mm	135-249mm	250-400mm
Sigma 100-400mm f/5-6.3 DG OS HSM C Lens			100-111mm	112-233mm	234-400mm
Sigma 150-600mm f/5-6.3 DG OS HSM Sports			150-184mm	185-320mm	321-600mm
Sigma 150-600mm f/5-6.3 DG OS HSM C			150-179mm	180-387mm	388-600mm
Tamron 150-600mm f/5-6.3 Di VC USD G2 Lens			150-212mm	213-427mm	428-600mm

Yes, this lens has an f/5.0 max aperture, but ... it is only available for 11mm of the focal length range, from 100mm through 111mm. That is enough to count and that is enough to give you f/5 in those cases where you must have it. Most of the differences shown in the above table are 1/3 and 2/3 stops.

This lens cannot create the shallowest depth of field in its class, but by virtue of its long focal lengths, it can create a strong background blur. I'll share an example of the background-elimination capability of this lens in the minimum focus distance discussion later in the review.

Image Stabilization

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Telephoto focal lengths magnify camera shake and faster shutter speeds are one way to retain sharp images at telephoto focal lengths. Without wide apertures helping to make fast shutter speeds available, this lens is disadvantaged. That is where Optical Stabilization (OS) saves the day, adding significantly to the versatility of this lens.

Usually, a manufacturer specifies the number of stops of assistance stabilized lenses are rated for, but I have not yet been able to find that specification for this lens. My experience using a Canon EOS 5Ds R in ideal conditions is that, at 100mm, I had decent keeper rate at a 1/13 second shutter speed with a relatively quick drop in sharp image percentages at longer exposures. Keepers trickled in through 1/5 second. At 400mm, the scenario was similar with 1/40 being the approximate exposure duration prior to the rapid drop-off in sharp image rate.

I'll talk more about the Sigma USB Dock later, but the dock permits this lens's OS to be further configured to one of three settings described by Sigma as:

Dynamic View Mode – This mode offers a recognizable OS effect to the image in the viewfinder. This helps to ensure the composition of images quickly.

Standard Mode – This is the default setting. The OS effect is well-balanced and suitable for various scenes.

Moderate View Mode – This mode offers an excellent compensation of camera shake, and achieves smooth transition of the image in the viewfinder. The composition of the image remains natural even when the angle of view keeps changing.

One of the great advantages of optical stabilization in a telephoto lens is the stabilized viewfinder making composition easier. However, in the default Standard mode, the image in the viewfinder shows only modest stabilization taking place. I much prefer the Dynamic View Mode for general purpose photography. The viewfinder becomes noticeably more stable than in Standard Mode.

In addition, Mode I (normal) and II (panning mode) are provided via a switch.

This OS system is rather quiet with some clicking/clunking being heard during operation including at startup and shutdown. At startup and shutdown, the scene in the viewfinder often bounces noticeably. Expect to see some noticeable drifting of framing while this system is in use. The drifting is especially noticeable if the lens is tripod-mounted and I suggest turning OS off when photographing in this manner.

Image Quality

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While this lens has a lot going for it from a physical perspective, the optical side of the evaluation always holds make or break potential. While I went into this review skeptical about a low-priced, lightweight lens delivering image quality that I liked, the lab tests quickly pointed toward the "make" side of the equation for this lens.

Is the Sigma 100-400mm f/5-6.3 DG OS HSM Contemporary Lens sharp? Yes. Quite sharp. And really nice is that quite sharp describes the wide open aperture performance of this lens. Typically, a lens is sharpest when stopped down one or two stops, but in this lens's case, there is not a lot of aperture remaining to stop down to and diffraction quickly becomes a limiting factor to sharpness when it is stopped down. So, wide open image quality is especially important here.

The 100-400 C is sharp wide open and there is little differentiation between focal lengths aside from the 400mm results being slightly softer than the wider options.

Our standard lab tests are great for seeing the capabilities of this lens (use the "Image Quality" link to see these results), but I also like to share some real world examples. The images below are 100% resolution crops captured in RAW format using a Canon EOS 5Ds R. The images were processed in DPP using the Standard Picture Style with sharpness set to only "1". These examples are from the center of the frame.

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I more-typically show examples of multiple apertures for each focal length, but ... there was little differentiation between them for this lens and they were not worth your time/bandwidth. And, the longer the exposure, the more that heat waves affect the sharpness under full-sun/clear-sky conditions, especially at 400mm.

Often a lens is noticeably sharper in the center than in the corners and this is another case where the Sigma 100-400 C at least somewhat breaks the norm as mid-frame and corner performance nearly matches the center. Extreme full frame corners show just a bit of softness. Here are some real-world examples showing the extreme bottom left corner of an ultra-high-res 5Ds R frame.

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A touch of softness is visible at 100mm, the 200mm result looks great and a bit of softness along with a bit of heat wave influence shows in the 400mm result. Again, stopping down resulted in little change.

One corner difference created by stopping down is reduction of vignetting. However, the amount of vignetting is not especially strong to begin with. Expect about 2 stops of shading in 100mm corners and about 1.6 stops of shading in longer focal length results. Stop the lens down to f/5.6 and 100mm delivers a similar amount of shading as the longer focal lengths do at the same/similar aperture. At f/8, approximately .8 stops of shading remains over the entire focal length range. This amount is just-visible in certain situations, such as a clear blue sky. At f/11, the wide end of the focal length range has a usually-negligible .3 stops of shading while the rest of the range retains slightly more – about .5 stops. Overall, this lens performs well in this regard.

If lens elements refracted all visible wavelengths of light identically, a lens designer's job would be a lot easier. Because they do not, we get aberrations caused by various wavelengths of light being magnified and focused differently.

The most easily recognized type of CA (Chromatic Aberration), lateral (or transverse) CA, shows as different colors of the spectrum being magnified differently with the mid and especially the periphery of the image circle showing color fringing along lines of strong contrast running tangential (meridional, right angles to radii) as this is where the greatest difference in the magnification of wavelengths exists.

Let's look at worst-case examples from each of the marked focal lengths of this lens. These are 100% crops from the extreme top-left corner of 5Ds R frames.

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There should be only black and white colors in these images and the additional colors illustrate lateral CA. At 100mm, there is moderately strong color misalignment and this issue is in part what caused the slight softness in the 100mm corner example shared above. Lateral CA diminishes until it becomes negligible at 300mm before becoming modestly noticeable again at 400mm (again having influence on the above 400mm corner sharpness result).

Fortunately, lateral CA is easily software corrected by radially shifting the colors to coincide. Unfortunately, other-brand camera manufacturers do not make Sigma lens correction profiles available for their cameras. That means lateral CA correction is not available for JPG format image capture and it means that this CA will be recorded in videos.

A relatively common lens aberration is axial (longitudinal, bokeh) CA, which causes non-coinciding focal planes of the various wavelengths of light, or more simply, different colors of light are focused to different depths. Spherical aberration along with spherochromatism, or a change in the amount of spherical aberration with respect to color (looks quite similar to axial chromatic aberration, but is hazier) are other common lens aberrations to look for. Axial CA remains at least somewhat persistent when stopping down with the color misalignment effect increasing with defocusing while the spherical aberration color halo shows little size change as the lens is defocused and stopping down one to two stops generally removes this aberration.

In the real world, lens defects do not exist in isolation with spherical aberration and spherochromatism generally found, at least to some degree, along with axial CA. These combine to create a less sharp, hazy-appearing image quality at the widest apertures.

If spherical aberration was a problem with this lens, we would most likely see sharpness improve with narrower apertures. It does not and I'm seeing only little evidence of any of the other issues. Below is the worst-case result I produced.

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These are 100mm f/5 100% crops showing the same subject with the lens focused in the foreground and then in the background. Notice the color fringing on the silver bracelet's specular highlights changing between the images. The longer focal lengths showed less of this issue and the above performance has not proven to be an issue either.

Put a bright light into a high element count telephoto lens (21 elements in 15 groups) and flare effects can be expected. This lens meets expectations, but does not exceed them. Note that the sun viewed in an optical viewfinder can cause rapid and irreparable eye damage, especially at telephoto focal lengths. It can also cause camera damage.

From a geometric distortion perspective, this lens has slight pincushion distortion at the wide end that slowly increases to a modest amount at the long end. Look at the bottom of the following images to see the lines in the bricks take on a curve.

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While no distortion would be better, this lens is not looking bad in this regard. Most will find that linear distortion matters less as the focal length increases.

This lens's bokeh, referring to the quality of the out-of-focus areas of the image, appears nice.

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The rounded 9-blade aperture creates nicely-rounded specular highlights. While these highlights have some concentric rings that can be seen around the borders (very normal), the outer transition is not harsh and the centers are smooth.

A 9-blade aperture stopped down will create 18-point sun star effects from point light sources, but ... doing that is not a strong capability of this lens. Here is an f/16 example:

I don't rate that one among the most attractive sun star effects I've seen lenses make.

As I indicated earlier, I find the image quality coming from this lens to exceed expectations. Overall, this lens has excellent image quality.

Focusing

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The 100-400mm Contemporary lens's AF system, like most of Sigma's other lenses, is driven by Sigma's HSM (Hyper Sonic Motor). This is a "contemporary" AF system and, with the optional and highly recommended Sigma USB Dock, this AF system is customizable.

The 100-400 C internally focuses quietly with only some faint shuffling heard and it focuses fast in the default "Standard AF" mode.

Using the dock, two custom modes are available for programming (via the dock), including AF speed options of "Fast AF Priority" and "Smooth AF Priority". Sigma has described Smooth AF Priority as offering a slightly slower but smooth autofocus (ideal for use with video) and Fast AF Priority seems self-explanatory though Sigma has indicated that it comes with a "... slight risk of decrease in accuracy". The programmed custom modes are then selectable via a switch.

Often I find that Sigma's Standard AF mode is considerably slower than the "Fast AF Priority" option and I usually make the latter my default because ... fast usually proves similarly accurate (I didn't perceive a difference with this lens) and ... I like fast. With the 100-400 C, I am struggling to perceive the differences in speed between any of the mode options even when testing them in various sequences one immediately after the other. They are similar enough that I thought I had not properly configured the custom modes and re-docked the lens to try again. I indeed had programmed them properly. All seem rather fast to me, and the difference between the slowest and the fastest mode seems minor.

I spent a solid amount of time testing this lens's AF accuracy on both Canon EOS-1D X Mark II and 5Ds R camera bodies. The day after I spent much of a day evaluating this lens's AF accuracy, Sigma released a firmware update with one of two feature updates being "Improved the AF performance." As I could no longer trust my work as being current, I updated to the latest firmware (an easy task with the Sigma Dock) and spent much of another day re-testing the lens.

Of course, the results of this testing are what you want to hear about and to cut to the chase, this lens focuses with decent accuracy overall and the relatively narrow max apertures make the AF performance modestly less critical. Most of the 100-400 C images were properly focused in One Shot AF mode, including both in-the-field and in more-critical testing. As is often the case, the peripheral AF points performed slightly worse than the center AF point.

Interesting is that, in a couple of tests, this lens focuses differently based on a foreground or background starting AF position. The above image shows 10 consecutive 100% crops captured using AF with a peripheral AF point selected. The first five images, shown in the left column, were captured with the lens pre-focused to the foreground. The second five images, shown in the right column, were captured with the lens pre-focused to the background.

In low light, this lens tends to hunt for focus a significant amount, but that behavior is not unexpected with a slow telephoto lens.

To test AI Servo continuous AF accuracy, I photographed a soccer match (one of many images I like from this match is included in the focal length discussion earlier in the review). While I captured a lot of great images that evening, I wasn't overly impressed by the focus accuracy I saw. I primarily selected peripheral cross-type AF points (with surrounding points enabled) for this testing as players' faces are seldom desired to be in the center of the frame.

AF consistency is the primary issue I test for, though focus calibration also matters a lot. My 100-400 C arrived properly focus calibrated for my cameras, but if a calibration issue was encountered, the dock stands ready to resolve that issue. The Sigma Dock allows focus calibration adjustments to be made at 4 focal lengths for 4 focus distances (16 total adjustments).

To (potentially) reduce autofocus hunting, autofocus distances can be restricted using the focus range limit switch. Distance ranges provided are Full, 19.69'(6m) - ∞ and 5.25'(1.6m) - 19.69'(6m). Using the dock and a custom mode, the autofocus range can be customized as desired.

FTM (Full Time Manual) focusing is available in AF mode (this feature can be disabled using the dock) and manual focus override (allows AI Servo AF to be overridden by turning the focus ring even during continuous AF) is another custom switch option.

A distance scale is provided in a window and as usual, the scale shows both feet and meter increments.

A modestly-sized (.95"/24.2mm) focus ring takes up position in a common location, just in front of the switch bank and behind the zoom ring. This ring has plastic (not rubber) ribs recessed into (vs. raised from) the ring. The rate of focus adjustment provided by the ring's 142° of rotation is nice at 100mm and rather fast 400mm. There is little play and the ring is nicely damped.

At 100mm, subjects remain similarly-sized as they go in and out of focus, but that is not the case at longer focal lengths and especially at 400mm where noticeable size changes occur (and subjects go in and out of focus rapidly). Focus at 400mm and the subject appears to remain in focus as the reviewed lens was zoomed out to 100mm.

This lens's 0.26x maximum magnification spec, achieved at 400mm at the 63.0" (1600mm) minimum focus distance, is a big asset to this lens. While this number is not best-in-class, it is among the best-available in zoom lenses and it is useful.

Here is a comparison table showing minimum focus distance and maximum magnification specs for similar-class lenses.

Model	Min Focus Distance "(mm)		Max Magnification
Canon EF-S 55-250mm f/4-5.6 IS STM Lens	33.5	(850)	0.31x
Canon EF 70-300mm f/4-5.6 IS II USM Lens	47.2	(1200)	0.25x
Canon EF 70-300mm f/4-5.6L IS USM Lens	47.2	(1200)	0.21x
Canon EF 100-400mm f/4.5-5.6L IS II USM Lens	38.4	(980)	0.31x
Nikon 80-400mm f/4.5-5.6G AF-S VR Lens	68.9	(1750)	0.20x
Sigma 100-400mm f/5-6.3 DG OS HSM C Lens	63.0	(1600)	0.26x
Sigma 150-600mm f/5-6.3 DG OS Sports Lens	102.4	(2600)	0.20x
Sigma 150-600mm f/5-6.3 DG OS C Lens	110.2	(2800)	0.20x
Tamron 150-600mm f/5-6.3 Di VC G2 Lens	86.6	(2200)	0.26x
Tamron 150-600mm f/5-6.3 Di VC Lens	106.3	(2700)	0.20x

The poppy shown below was captured at this lens's maximum magnification/minimum focus distance.

This flower is just-over 3" (75mm) in width. Also nicely illustrated here is how diffusely 400mm and f/6.3 can blur the background when used at a close focus distance.

Magnification from telephoto focal length lenses can be increased modestly by the addition of extension tubes. Extension tubes are hollow tubes (with electronic connections) that shift a lens farther from the camera. Doing so allows the lens to focus at closer distances, though at the expense of long distance focusing.

Providing significantly more magnification capability to this lens are teleconverters. The 100-400 C is compatible with the Sigma TC-1401 1.4x and TC-2001 2x Teleconverters, respectively generating a 1.4x and 2x increase in both focal length range and MM values.

The 1.4x TC creates a 140-560mm lens, closely matching many of the other zoom lens options shown in the above table. Not so closely matching is the 1-stop-narrower max aperture this teleconverter creates, making this a dark f/7.1-9 lens. As mentioned earlier, many cameras require an f/5.6 max aperture for conventional phase detection AF to work and the best require f/8. Expect, minimally, focus hunting to be a common issue. Live View and other sensor-based AF systems can often AF with lenses as dark as f/11, so that option remains available.

The viewfinder is not terribly bright with an f/6.3 max aperture and it will noticeably darken with the 1.4x in place.

When the base image quality of a lens is magnified, defects are also magnified and I was not expecting good results with teleconverters behind this lens. Surprisingly, this lens does not show much sharpness degradation with the 1.4x behind it and the added barrel distortion offsets some of the lens's native pincushion distortion. A downside is that lateral CA is increased.

Addition of the 2x TC makes this a impressive 200-800mm lens. Much less impressive is the resulting f/10-13 max aperture and equally unimpressive is the sharpness of this combination that is diffraction limited wide open on many current and recent model cameras. Additional lateral CA and reduced barrel distortion are two more attributes of this combination.

Build Quality & Features

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To keep this lens light and inexpensive, Sigma once again features Thermally Stable Composite (TSC) materials along with traditional metals in the design. While there is some plastic feel to the lens, the quality finish gives it a nice touch and provides a classy look. The shape makes the 100-400 C comfortable to use.

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Most zoom lenses reaching to 400mm extend at their longest focal length and this one stays the course, extending up to 2.38" (60.5mm). With that much extension happening, some play in the extension may be expected, but that is not the case with this lens. The extending lens barrel, rings and switches all have tight tolerances with no play.

The focus ring is not the easiest to locate via tactile methods and the partially-ribbed barrel is partly to blame, but the large zoom ring is definitely prioritized for use. The crisply-ribbed, substantially-sized rubber zoom ring is smooth with an ideal rotational resistance (I didn't notice that the zoom ring ribs are slightly twisted on this lens copy until looking at the product images). This ring's 80° of rotation provides an ideal rate of transition between focal lengths. The 100-400 C zoom ring rotates in the Canon-standard direction (opposite of the Nikon standard).

A front-positioned zoom ring and rear-positioned focus ring is not my preferred design. This lens balances on a non-gripped camera at around the switch bank position. The switch bank is not as comfortable to grasp as just in front of it and I find my left hand typically holding under the focus ring. This means that any movement of that hand after focusing (such as when recomposing) can change the focus distance setting and that of course can mean an out of focus image. This design also means that the lens is unbalanced when using the zoom ring, requiring the right hand to aid in supporting the weight during that process. All that said, this is the normal design for lenses in this class and it works fine.

This lens has, minimally, a dust & splash proof mount as indicated by the rear gasket seal. In the press release, Sigma mentioned a "dust- and splash-proof design", hinting that the lens has sealing throughout. I used the lens in light rain prior to photographing the rainbow and had no issues. The front and rear elements of this lens receive a water & oil repellent coating.

If this lens is pointed downward and some movement is occurring (such as walking), gravity will extend the lens to a longer focal length. To prevent this, Sigma provides a zoom lock switch. Unlike some of Sigma's other recently introduced telephoto zoom lenses, this one can be locked into the fully-retracted 100mm position only.

Aside from the lock switch, 3-position switches are standard on this lens. It is easy to misposition a short-throw 3-position switch such as these and care must be exhibited to achieve the middle switch positions (commonly used Mode I OS for example). Classy-appearing is the white backgrounds on the AF and lock switches, visually indicating their set positions. I'll talk more about the Custom switch under the dock subheading below.

Sigma has obviously made light weight a priority for this lens. This lens can easily be handheld for long periods of time. I'm not saying that you will not eventually get tired of holding this lens, but I am saying that most people will find it usable handheld in many situations. Here is a comparison chart to put everything in perspective.

Model	Weight oz(g)		Dimensions w/o Hood "(mm)		Filter	Year
Canon EF-S 55-250mm f/4-5.6 IS STM Lens	13.2	(375)	2.8 x 4.4	(70.0 x 111.2)	58mm	2013
Canon EF 70-300mm f/4-5.6L IS USM Lens	37.1	(1050)	3.5 x 5.6	(89.0 x 143.0)	67mm	2010
Canon EF 70-300mm f/4-5.6 IS II USM Lens	25.1	(710)	3.1 x 5.7	(80.0 x 145.5)	67mm	2016
Canon EF 100-400mm f/4.5-5.6L IS II USM	55.4	(1570)	3.7 x 7.6	(94.0 x 193.0)	77mm	2014
Nikon 80-400mm f/4.5-5.6G AF-S VR Lens	55.4	(1570)	3.8 x 8.0	(95.5 x 203.0)	77mm	2013
Sigma 100-400mm f/5-6.3 DG OS HSM C Lens	40.9	(1160)	3.4 x 7.2	(86.4 x 182.3)	67mm	2017
Sigma 150-600mm f/5-6.3 DG OS HSM C Lens	68.1	(1930)	4.1 x 10.2	(105.0 x 260.1)	95mm	2015
Sigma 150-600mm f/5-6.3 DG OS Sports Lens	101.0	(2860)	4.8 x 11.4	(121.9 x 289.6)	105mm	2014
Tamron 150-600mm f/5-6.3 Di VC G2 Lens	71.0	(2010)	4.3 x 10.2	(108.4 x 260.2)	95mm	2016
Tamron 150-600mm f/5-6.3 Di VC Lens	68.8	(1950)	4.2 x 10.1	(105.6 x 257.8)	95mm	2013

For many more comparisons, review the complete Sigma 100-400mm f/5-6.3 DG OS HSM C Lens Specifications using the site's Lens Spec tool.

Putting a visual to the chart, here are Nikon and Canon's most-similar lenses beside the Sigma:

Positioned above from left to right are the following lenses:

Nikon 80-400mm f/4.5-5.6G AF-S VR Lens
Canon EF 100-400mm f/4.5-5.6L IS II USM
Sigma 100-400mm f/5-6.3 DG OS HSM C Lens

The same lenses are shown below with their hoods in place.

Use the site's product image comparison tool to visually compare the Sigma 100-400mm f/5-6.3 DG OS HSM C Lens to other lenses. I preloaded a comparison that you might find interesting and there are many other good comparisons to be made.

For the size of this lens, it uses relatively small and common 67mm filters. In keeping with the overall low cost of this lens, 67mm filters are relatively inexpensive. Note that a thin-ringed filter is difficult to access with fingertips due to the thickness of the lens barrel at the threads. I always recommend having a filter wrench on hand, but especially recommend having one readily available with this lens if using a circular polarizer filter or other thin-rimmed filter.

Not included and not optionally available for the 100-400 C is a tripod ring. Removal of this feature aids in the compactness, weight savings and low price enjoyed by this lens, but ... you may miss this feature. While small and light for its class, this is a large, heavy lens to be hanging from a camera mounted to a tripod or monopod and you can expect even a strong tripod and head to sag a bit when locking it down. This makes careful frame alignment a bit challenging, requiring prediction of the final sag. The lack of a tripod ring also makes vertical orientation more difficult to use. When using a monopod, a monopod head or L-plate is needed to use the camera in vertical orientation and the additional time required to change orientation will not go unnoticed when photographing action including sports.

The rigid plastic Sigma LH70-04 Lens Hood is included in the box. This is a moderately large hood that provides plenty of protection to the front lens element – protection from flare-inducing light, protection from impact, protection from dust and moisture, etc. The interior of the lens is ribbed to avoid light reflecting into the lens and the front of the exterior is ribbed in the other direction to aid in grip during installation and removal. The rear of the hood is contoured significantly, permitting the lens to be push-pull zoomed from this grip position.

No lens case is included with the 100-400 C, but you can likely find a Lowepro Lens Case to meet your needs.

Sigma Global Vision and the Dock

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Sigma's Global Vision lenses (this is one) get a classification of "A", "C" or "S", representing a primary Sigma-intended designation of "Artistic", "Contemporary" and "Sports". A full description of these categories can be found in the Sigma 35mm f/1.4 Art Lens press release.

As I've overstated, I am not a fan of the rather narrow categorization structure. This lens gets a "C" stamped in a classy chrome circle on the lens barrel. While "Artistic" and "Sports" give direction toward their suggested use, "Contemporary" is more vague. Are not all lenses being newly introduced "Contemporary"? And, what happens when "Contemporary" lenses become 15 years old? While this lens is currently a "Contemporary" one, it can be used for sports photography and it is at least as well-suited for wildlife and landscape photography, which lack their own categories. There is also no reason why artistic images cannot be captured by this lens.

I have also not been shy about stating that I am a fan of what Sigma is doing with the Global Vision lineup. The lenses in this series continue to impress and gain popularity – just don't limit the lens's use to its letter designation.

A great feature of the Global Vision lenses is compatibility with the Sigma Dock. The dock, working in conjunction with the Sigma Optimization Pro software, allows the lens's firmware to be updated (bug fixes, compatibility updates, feature enhancements, etc.) and allows precise autofocus calibration at four distances for four focal lengths.

Load Comparison Images

The second row of options illustrate what is available for programming into the C1 and C2 Custom switches. These settings become immediately available at the throw of a switch. I programmed Custom switch 1 to "Motor's drive speed priority" and "Dynamic View Mode".

Price, Value, Compatibility

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The price is relatively low and the usefulness of the lens is high. The image quality this lens delivers competes with much more expensive models and this is a full-featured lens (well, the tripod ring is missing). What you get for the price makes this one a bargain.

The Sigma 100-400mm f/5-6.3 DG OS HSM C Lens is available in Canon (reviewed), Nikon and Sigma mounts and the Canon and Sigma versions can be used on a Sony E-mount camera body via the Sigma Mount Converter MC-11. This lens qualifies for Sigma's Mount Conversion Service in case you later change your mind. My standard disclaimer: There are potential issues with third party lenses. Since Sigma reverse engineers (vs. licenses) manufacturer electronics and algorithms, there is always the possibility that a DSLR body might not support a (likely older) third party lens. Usually a lens can be made compatible by the manufacturer via a firmware update, but this cannot be guaranteed. Compatibility with the Sigma USB Dock is risk reducing as Sigma can release firmware updates for dock-compatible lenses. Sigma USA provides a 4-year limited warranty.

The reviewed Sigma 100-400mm f/5-6.3 DG OS HSM Contemporary Lens was online retail-sourced.

Alternatives to the Sigma 100-400mm f/5-6.3 DG OS HSM Contemporary Lens

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Which telephoto lens should I get? That may be a question you are asking right now. There are a LOT of options, but if the 400mm focal length is needed, those options are quickly narrowed down.

Many of the remaining options are the 150-600mm telephoto zooms included in the above table comparisons. While these lenses offer significantly longer focal lengths, they are much larger and heavier and are, essentially, in a different lens class.

Remaining are the Canon and Nikon options.

Canon owners have the incredible Canon EF 100-400mm f/4.5-5.6L IS II USM Lens to consider. The image sharpness and overall quality of the 100-400 L II launched it to immediate success. I didn't expect the Canon vs. Sigma comparison to be close, but ... I was wrong. I'm not saying that the Sigma is sharper than the Canon (the Canon advantage is most-noticeable at 400mm), but the Sigma is much closer than its much-less-than-half price would indicate. The Canon has less vignetting and shifts the distortion profile toward the barrel distortion side, taking on a bit of barrel distortion at 100 and giving it both a near-0 distortion setting and a touch less distortion at the longer end of the focal length range. The Sigma is smaller and lighter and uses smaller filters (67mm vs. 77mm), but the Canon has wider apertures, a tripod ring and has a higher maximum magnification (0.31 vs. 0.26x). The Canon AF system is my preference.

Nikon owners should opt to compare the Nikon 80-400mm f/4.5-5.6G AF-S VR Lens. In the Sigma vs. Nikon comparison, I see the Nikon delivering similar sharpness at the wide end, but the Sigma pulls away at the longer end. The Nikon has less vignetting, but priced similarly to the Canon, costs more than twice as much as the Sigma. The Sigma is smaller and lighter, uses smaller filters (67mm vs. 77mm) and has a higher maximum magnification (0.26x vs 0.20x). The Nikon has wider apertures and a tripod ring.

If you can drop down to 300mm on the long end, more options open up, including the Canon EF 70-300mm f/4-5.6 IS II USM Lens and Canon EF 70-300mm f/4-5.6L IS USM Lens. Use the site's image quality and other tools to see how these lenses compare.

Summary

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If you've stayed with me throughout this entire review, you know the final story. The AF accuracy could be slightly improved and a tripod ring would be nice to at least optionally have available, but otherwise, the 100-400 C gives you a useful range of focal lengths in a relatively small and light, nicely-designed, full-featured package. This is a lens that you will want to take with you and that alone means you will capture more images. The great image quality for a reasonable price seals the deal on this one. The Sigma 100-400mm f/5-6.3 DG OS HSM Contemporary is another lens warranting kit-addition consideration.