Archive for Canon 100-400mm lens

Sigma 50-500mm f4.5-6.3 APO DG OS HSM Lens Review – A Field Test

Posted in Articles about Photography, Lens Review, Photography Gear, TCBlog, Videos with tags , , , , , , , , , , , , , , , , , on June 21, 2011 by Darwin

Note: To see all future reviews please note this blog is no longer active, please visit me over at oopoomoo.com

Recently Sigma Canada lent me a copy of their new 50-500mm f4.5-6.3 DG OS HSM lens to try out on my Spring Photo Tour in the Canadian Rockies. I used the lens for six days in a variety of conditions and took hundreds of photos. Here is what I thought of the big lens with the 10x zoom! Note: all sample images were made with a Canon EOS-1ds Mark III full frame camera.

The Background

Listed below are the ‘features’ of the lens that might entice someone to consider this piece of glass:

  • crazy all-in-one 10x zoom range; 50-500mm on a full frame camera or 75-750mm lens on an APS-sized camera!
  • optical stabilization feature for a 2-4 stop shutter speed advantage for hand-held photography.
  • HSM (hyper-sonic motor) for silent auto-focus.
  • low dispersion glass elements for best lens performance.
  • ‘reasonable’ price for a lens with these capabilities (approx. $1800 CAN, street price).

The Results

OK, so what’s not to like about a lens that goes from the normal point-of-view of the human eye to pinpoint telephoto images? How much zoom is 10x in the real world? The two images of the below highlight the incredible zoom range in action and show the same subject photographed from the same position (in my car) only seconds apart.

©Darwin Wiggett - Bear at 50mm with the Sigma 50-500mm lens

©Darwin Wiggett - Bear at 500mm with Sigma 50-500mm lens

During my spring photo tour I mostly used two lens; my trusty Canon 24mm TS-E (tilt-shift lens) for big wide-angle scenes and the Sigma 50-500mm lens for everything else. I loved the flexibility of the zoom range of the big Sigma lens from normal for generic landscape photography to telephoto for skittish wildlife and distant scenes. The more I used the lens, the more I liked rarely having to change lenses and the better prepared I felt for any photo opportunity! I could frame and zoom on the fly and get things I would have missed if I had to change lenses.

©Darwin Wiggett - Sigma 50-500mm at 500mm, 1/40s at f6.3

©Darwin Wiggett - Sigma 50-500mm lens at 58mm, 1/4s at f14

Besides loving the zoom range and the flexibility of the lens I also really liked the build quality and the operation of the zoom and focus rings. Best of all the lens was snappy and fast to focus and auto-focus was accurate on my 1ds Mark III. The OS (optical stabilization) worked well down for me down to about 1/60th of a second hand-held even at 500mm. I was able to walk around and photograph wildlife without a tripod and the lens seemed to grab focus the majority of the times (except in very low contrast light).

©Darwin Wiggett - Sigma 50-500 at 500mm, 1/250s at f6.3

500mm at f6.3 - detail at 100%, no post production sharpening

I also liked the ability of the lens to focus close at all focal lengths. I could make images of flowers and hummingbirds and other small subjects from a distance and nearly fill the frame. I cropped the image slightly to make a more squarish presentation but even at this distance I was not a minimum focus.

©Darwin Wiggett - Sigma 50-500mm lens at 500mm, 1/250s at f6.3

All in all the lens was a joy to use because of its crazy zoom capabilities and responsive auto-focus. I felt like I could photograph anything I could see and I certianly got images that I would not get with a kit full of prime lenses or regular zooms because the opportunity would be lost when changing lenses.

©Darwin Wiggett - Sigma 50-500mm at 413mm, 1/15s at f10

©Darwin Wiggett - Sigma 50-500mm at 167mm, 1/400s at f5.6

Ok, so the zoom range is fantastic… but what about sharpness?

Sharpness is subjective. In the end, is the sharpness of the lens going to suit your purposes? Are you selling professionally, do you make mega-big prints or will you never make anything over 12×18 inch prints? What is sharp for one person is crap for another….

When I test lenses for myself, I have a simple subjective scale for lens sharpness:

  • Excellent (the rating for sharpest lenses I have tried e.g. macro lenses or prime short telephoto lenses like an 85mm or 135mm lens). Does the tested lens match up to these levels of sharpness?
  • Very Good (good zoom lenses like a 70-200mm lens, or a prime 50mm lens would fall into this category).
  • Good (decent zooms producing professional or nearly professional quality).
  • Acceptable (good enough to make a nice 12×18 prints with a post-production sharpening)
  • Crap (Coke bottles are better than this)

Most lenses I have ever tried are normally in the good (consumer lenses like a 70-300mm f5.6) to Very Good range (pro level lenses like a 24-70mm f2.8 lens). Some lenses have sweet spots. Some lens are sharp in the center but crappy on the edges. Some zooms are better at some focal lengths than others. Some lenses are optimized for sharpness wide open while others need to be stopped down a bit for good performance. You can spend a lot of time testing every possible permutation and other sites offer this information on the web by running the lens through bench tests in the lab. But for me, I just want to know what I can get in the field with a lens and if the results give me what I need (publishable sharpness). I am lens interested in optical bench tests.

Based on my field tests making actual images in the field I would rate the sharpness of the Sigma 50-500mm lens as follows:

  • 50mm – Acceptable
  • 100mm – Good-
  • 135mm – Good
  • 200mm – Very Good
  • 300mm – Very Good
  • 400mm – Good +
  • 500mm – Good –

The lens seems to have a sweet spot for sharpness in the 200-300mm range. I found the 400mm images from the Sigma 50-500mm lens to be sharper than the 40omm images taken with a Sigma 120-400mm lens or the Canon 100-400mm lens so I would say this is a great lens to use in the 200-400mm range. I think 50-150mm  is the weakest performing range of this lens.

©Darwin Wiggett - Sigma 50-500mm lens at 332mm, 1/25s at f10

At 500mm the Sigma is decent but of course it’s nothing like a 500mm prime (I have tried the Canon 500mm f4L and would rate it as Very Good). I got publication quality photos with the Sigma 50-500mm lens at 500mm and even though it does not perform to the levels of a 500mm prime, it still gives decent results. Everything is a compromise, even if you could afford a 500mm prime ($6000-$9000 CAN) would you constantly carry the giant beast in your camera bag (over 8lbs)? With the 50-500mm it was small and light enough that I actually had the lens with me all the time and got shots at 500mm that I would have missed if I owned a 500mm prime (because I would have left the lens in the car). Sharpness is the be-all for some photographers, but having a great shot that is a little softer but useable is better than having no shot at all!

©Darwin Wiggett - Sigma 50-500mm at 500mm, 1/25s at f10

©Darwin Wiggett - Sigma 50-500 at 450mm, 1/640s at f7.1

The Dislikes:

No lens is perfect and the 50-500mm lens has some flaws that may make or break it for you:

  • 95mm front lens element means the lens is hard to filter. I managed to use a polarizer and ND filters by using a Cokin Z-Pro Holder and a Cokin Z-Pro 95mm adapter ring but using filters on this lens will cost you big bucks to buy Z-Pro or Lee sized filters. This is not an easy lens to filter.
  • if you use 1.4, 1.7 or 2x extenders you will not be able to auto-focus your lens (manual focus only). I would not recommend extenders for this lens as sharpness suffers to non-acceptable levels. Plus who needs an extender when you got this much zoom range?
  • the lens is less contrasty than Canon or Nikon lenses and sometimes the colours seem a bit flat (but for me that was an  easy fix in  JPEG camera settings or in RAW conversions).
  • when I use live view and manual focus I love it when the lens stays sharply focused no matter what focal length I zoom to (like my Sigma 120-400mm lens does) – the 50-500mm lens needs to be refocused every time you change the zoom setting (frustrating for the way I shoot). But when auto-focus is used, the lens is zippy and so refocusing is less of a chore.
  • the weight and bulk turns some people off but it is only a tad bigger than the Canon 100-400mm lens and for what you get I think the lens is actually surprisingly small.
  • like all big lenses, to get optical sharpness requires precision in technique – this lens requires a super robust and sturdy tripod for any shots less than 1/60th or 1/125th of a second. People might complain that this lens is not sharp but chances are good it’s an inadequate tripod problem and not a problem with the lens! For longer shutter speeds, 1/30th of a second or longer,  mirror lock-up and a remote release are a must! It is difficult to get a sharp shot with this lens at slow shutter speeds unless you are using proper technique and have a super solid tripod and tripod head.
  • this lens (and many super long lenses) doesn’t do great with distant subjects; atmospheric haze, heat shimmers and other atmospheric effects can reduce apparent sharpness in long lenses and long zoom settings; realize this is not a issue with this lens but is a a long telephoto issue in general.
  • the lens vignettes (slight darkening of corners) at all focal lengths in apertures from f4.5 to about f9.0. I don’t mind this because I often purposefully add vignetting to my photos in post because I like the effect (the vignetting can easily be fixed in Camera RAW). But some people demand and need even exposures across the frame.
  • the lens does suffer from fringing at the edges of the frame with full-frame cameras when the lens is in the 50-150mm range and shot in contrasty light (this can easily be corrected in Camera RAW in Photoshop or Lightroom). If you plan to shoot JPEGS and do not want to spend time correcting fringing, then this lens might be problematic for you.
  • edge sharpness on full frame cameras is about one quality factor from center sharpness (but this is common with most lenses).  On APS-sized sensors both edge vignetting and edge sharpness concerns disappear because of the crop factor of the camera.

©Darwin Wiggett - Sigma 50-500mm at 450mm with a Cokin P173 Blue-Yellow polarizer, 1/4s at f16

Below is an image shot at 50mm with the Sigma 50-500mm lens and the image that follows shows the fringing at the edge of the frame in contrasty light.

©Darwin Wiggett - Sigma 50-500mm lens at 50mm, 1/1600s at f10

Colour fringing at the edges of the frame at 50mm with the Sigma 50-500mm lens

Conclusion

I was super skeptical about this lens. Any lens with a 10X zoom range I am ready to write off as crappy in terms of image quality. I told Sigma I would test it but that they should be prepared for a completely honest review. I was prepared to pan this lens. But I was wrong.

Sure the lens is not as sharp as a 300 or 500mm prime lens, but who would expect it to be? I was surprised by how good this lens actually was especially in the 200-400mm range. It was decent at 500mm and yields publication quality images (with a little help from post-production sharpening). The weak spot in the lens is the 50-150mm range where sharpness and fringing are problems that need to be fixed in post-processing. Also this lens needs to be used with proper techniques to yield optimal results.

©Darwin Wiggett - Sigma 50-500 at 244mm, 1/30s at f13

The one thing that caught me off guard is how much I loved the zoom range and how I felt I was ready to capture any subject from intimate details, to landscapes both grand and extractive, to wildlife all with one lens. I got addicted to having one do it all (and more) lens on my camera. How liberating! And surprisingly I found that long lens settings in the 400-500mm range made up the vast majority of my landscape work with this lens.

If I was going on a trip that was a combination of generic nature photography where I might expect grand landscapes, wildlife and intimate details, then I would be tempted to take just two lenses; a 24-70mm f2.8 and the 50-500mm lens. Two lens and I am covered for every possibility! In fact next year I am going to Iceland and these two lenses might be my perfect travel companions.

©Darwin Wiggett - Sigma 50-500mm lens at 167mm, 1/60s at f5.6

The Dilemma

Sigma lenses are made to fit Canon, Nikon, Pentax, Sony, and Sigma cameras so if you have one of these camera systems, then you might consider the Sigma 50-500mm lens. The problem is Sigma makes a few long range telephotos to choose from and so your choices become a bit difficult:

Sigma 50-500 f4.5-6.3 – reviewed above ($1800 CAN)

Sigma 150-500mm lens f5-6.3 – (street price $1200 CAN)

Sigma 120-400mm lens f4.5-5.6 – see my review here (street price $1000 CAN)

Which one to buy?? It all depends on what you own already, your needs, your photographic subjects etc. I bought the 120-400mm lens after I reviewed it because I liked it better than Canon’s 100-400mm lens and I liked that I could filter the lens easily (77mm filters which I already own). Plus I already have a 70-200mm lens. That choice made sense for me. Look at the specs of each of these lenses and check out several reviews to decide if any of these lenses shoot your shooting style and budget.

For an all round nature shooting I would be happy with either the 50-500 or the 120-400mm lenses. I have not used the 150-500mm lens. If I planned to be a wildlife specialist, I would save up my coin for a fast prime lens (300mm f2.8, 500mm f4 or a 200-400mm f4 or Sigma’s new 120-300 f2.8) but all of these these lenses are very expensive and very heavy. There is no perfect lens but with a little research you can find one that is a good match for you. Good luck!

Full disclosure: I am sponsored by Sigma Canada. I give fully honest reviews of what I think but for some people the issue of ‘sponsorship’ might colour their view of this review. I only accept sponsorship from companies where I am allowed to say whatever I think, Sigma Canada allows this. If you buy from B+H Photo I will get a small percent of the sale that helps support this website.

If you want to buy the 50-500mm lens in the USA I recommend B+H Photo (good service and prices and they support this website) and for Canadian customers please support The Camera Store – the best place to buy any camera stuff in Canada (a biased but honest opinion!).

I hope this field review has been useful. Feel free to comment but keep things polite and reasoned and offer useful input that will help others make informed decisions. Name-calling, thoughtless comments or personal attacks on anyone will not be tolerated and those comments will be removed. Play nice!

©Darwin Wiggett - Sigma 50-500 at 167mm, 1/4s at f13

©Darwin Wiggett - Sigma 50-500 at 167mm, 1/10s at f10

©Darwin Wiggett - Sigma 50-500mm lens at 500mm, 1/250s at f6.3

Lens Review: The Sigma 120-400 4.5-5.6 APO HSM Telephoto Zoom

Posted in Photography Gear, Techniques with tags , , , , , , , , , on February 23, 2010 by Darwin

First the preamble:

I am a working landscape photographer. I am not a lab technician. I do tests in field conditions shooting with the gear just like I normally do. I do not take photos of lens charts or do studio tests. I want to know how well a lens or camera works in the field. I am not paid to do these reviews nor do I get a kick back for any sales of products reviewed. I do not get free camera equipment nor am I sponsored by any camera or lens manufacturers. I am only interested in finding decent gear at a fair price. When I do find a ‘good buy’ I will share my findings with others and then you can decide if the gear will be a good fit for your shooting style.

Note: To see all future reviews please note this blog is no longer active, please visit me over at oopoomoo.com

The Backgound

Anyone familar with my work knows I use Canon cameras and Canon Tilt-Shift lenses for the majority of my landscape work. Overall I am pretty happy with the gear I use and when I am not I freely express what I think are the short-comings of the gear (which probably has not made Canon happy at times).  🙂

What is less well known is that I love telephoto zooms to create ‘extractive landscapes’ (like the one below). I carry a little Canon 70-200 f4L lens in my pack and a Canon 300mm F4L IS lens to cover my telephoto needs. When the 70-200mm does not supply enough reach, I switch to the 300mm. I am happy with these two Canon lenses but sometimes I wish I had all that zoom range in one lens. So I thought I would test the Sigma 120-400mm lens. I chose this lens for it useful focal range, the fact that it accepts 77mm filters (I love filters!), the fact that it is not too crazy heavy (1750 grams) and the fact that it is affordable (about $1000 CAN). I also compared it to Canon’s 100-400 f4.5-5.6L lens which I used to own but sold because I was not a huge fan of the lens (but maybe that was a mistake–we’ll see).

©Darwin Wiggett

The Procedure

In the field I used a solid Gitzo tripod and a Really Right Stuff BH-55 ball head to support the camera and lenses. I used mirror lock-up, a cable release, no filters, and used live view to focus. I have tested my Canon EOS-1ds Mark III extensively and I get sharper photos using Live View at 10x magnification than I can get with the camera using auto-focus even after focus calibration . I also turned off Optical Stabilization (Sigma) and Image Stabilization (Canon) for all tripod shots. I shot near and distant scenes. Here are my findings:

The Lenses Tested

The lenses compared from left to right:

Sigma 120-400 4.5-5.6 APO, Canon 100-400 f4.5-5.6L, Canon 70-200 F4L and Canon 300mm F4L

First Impressions

I was impressed by the build quality and handling of the Sigma lens. It felt sturdy, and the focus and the zoom mechanisms were smooth and silky. The lens did not feel ‘cheap’ or clunky in any way. The zoom ring is at the front of the lens and a half twist of the hand takes you quickly from 120 to 400mm. Most Canon lenses have the focus ring in the front of the lens and the zoom ring behind so it took me some time to get used to having the opposite arrangement with the Sigma lens. The Canon 100-400 lens has a push-pull zoom that also takes a little getting used to. People that own the 100-400 either love or hate that push-pull zoom, few people are neutral about it. Sigma’s rotating zoom is probably more acceptable to a wider audience.

The Sigma 120-400 and the Canon 100-400 zoomed out to 400mm

An interesting note about the Canon 100-400mm. Numerous photographers I know refer to the Canon lens as the Vacuum Cleaner. Take the back lens cap off the 100-400 and cup your hand over the rear lens element. Now push and pull the zoom back-and-forth. You’ll get a good stong flow of air sucking in and out of the lens. Guess what moving air attracts? Dust. A fairly common complaint with the Canon 100-400mm lens is that it is a big dust sucker leaving you with a dirty camera sensor. I tried the same test with the Sigma lens and there is still airflow while zooming but significantly less than with the push-pull Canon Lens. If you want to vacuum your carpet as well as take photos, then the Canon 100-400 might be a good choice 🙂

Sharpness Tests

I compared all the lenses at every aperture and at numerous overlapping focal lengths. Rather than bore you with pages and pages of 100% screen captures just let me summarize my findings below. You’ll need to take a leap of faith that I did my best to make the field comparisons as fair as possible and to keep shooting conditions as controlled as I could. I repeated the tests three times to confirm my initial findings. I will include a couple of critial comparison for visual reference. Also I will let you know about my preconceptions before the test so you know what I expected to find (my bias). I assumed that the 70-200 f4L and the prime 300 f4L would outperform both the Canon 100-400 and the Sigma 120-400. Also I expected the two big zooms would probably be close in quality.

Sharpness and Aperture

Lenses all tend to have a sweet spot where there are one or two apertures that give the best resolution or sharpness performance. All four of the lenses tested here had the best sharpness at apertures of f5.6 to f11 with f8 being the sweet spot for all the lenses at all focal lengths. For example, I photographed the image below with the Sigma 120-400 at 200mm.

Shot with the Sigma 120-400 lens at 200mm

 In the 100% magnified view of the same scene you can clearly see that apertures larger than f11 start to lose edge sharpness.

100% view of Sigma 100-200 at 200mm based on aperture

All of the Canon lenses used in this test had a minimum aperture of f32. I would happily use any aperture on any of these lenses from wide open to f11. Even f16 was acceptable in most cases. But f22 and especially f32 are useless apertures in my opinion due to loss of sharpness through diffraction. Below is a 100% view of a photo of a fence in my backyard showing a comparison of f11 and f32 using the Canon 100-400mm lens at 200mm – the differenes are striking. I repeated this test three times in different light and with all the Canon lenses–in the end I found that  f22 and 32 are useless if you want pro caliber results and/or the capabilities to make large prints.

Canon 100-400 at 200mm

Vignetting

Often zoom lenses will show some uneven exposure across the frame at wide open apertures where the edges and corners of the frame are darker than the center. Usually one or two apertures down from wide open and exposure across the frame evens out. The photo below shows the lens vignetting for the Canon 100-400 at 120mm (left) and the Sigma 120-400mm at 120mm (right). By f11 the exposure totally evens out for both lenses. The Sigma seems to suffer from a bit stonger lens vignette than the Canon. The other interesting difference is in the colour between the lenses. The settings on my Canon EOS-1ds Mark III were exactly the same for both sets of pictures and the sets were taken only minutes apart. The Sigma lens renders colours much warmer than the Canon lens.

Lens Vignette Test, Canon 100-400 on left, Sigma 120-400 on right

I found that the Canon 70-200 F4L and the 300 F4L have slightly less lens vignette than the  the two big zooms and that the exposure across the frame is even at f8.0. Whether lens vignette is a problem for you depends on what you shoot and your style. Correcting vignette is easy in Adobe Camera Raw and in Adobe Lightroom so if you like to shoot wide-open alot then you may need to correct this problem in post-production. But frankly, most people are purposely adding a vignette effect to their photos so I really think only the most anal photographer would be bothered by the vignetting seen on any of these lenses. But do note, the Sigma has the greatest lens vignette of all the lenses tested.

Sharpness comparisons

I tested all four lenses in the field using various subjects but the the three scenes that showed the differences in sharpness the best were the photos below. One image (the trees) was shot in overcast light, while the wooden fence and the chain link fence with signs were shot on a sunny evening . I  compared the sharpness of Sigma lens with the Canon lenses based on these three scenes.

The scene used to compare lens sharpness

Scene used to compare lenses on overcast day

Scene used to compare lens sharpness

Canon 70-200f4L vs Sigma 120-400mm lens

When I compared the Sigma 120-400 with the Canon 70-200f4L I was surprised by how well the Sigma lens performed. Both lenses seemed sharpest at f8. At the tested focal lengths of 120mm and 200mm there was little to distinguish the two lenses in terms of sharpness. The Canon slightly edged out the Sigma at f5.6 but  after that they were about even in sharpness until f16 when the Sigma had a tiny edge. Really I could not see much of a difference between the two lenses.  Below is a comparison of center sharpness in both lenses at f8. Do note the slightly bluer colour cast to the Canon lens

Canon 70-200f4L vs Sigma 120-400mm lens - Center Sharpness

Where I did notice some differences between the lenses was at the edges of the frame. The Canon is better controlled at lens vignette at wider apertures but when it comes to edge sharpness the Sigma came out on top at all apertures tested. The disturbing thing about the Canon 70-200 f4L was that there was some colour fringing (magenta) at the edges of the frame (see photo below). Maybe Canon needs to update this lens to a Mark II version to overcome this flaw. For me as a landscape shooter, I like the files I got from the Sigma in the 120-200mm range better than the files that came from the Canon 70-200 f4L.

Canon 70-200 F4L vs. Sigma 120-400mm lens - edge sharpness

Canon 300mm F4L vs Sigma 120-400mm lens

For me this test was a no brainer, I figured that the prime Canon 300mm lens would easily surpass the Sigma lens in terms of sharpness–a prime versus a big range zoom–c’mon! But, I was impressed by the Sigma lens. At 300mm, at almost every aperture, the Sigma zoom could easily match the sharpness of the Canon prime. At f5.6 the Canon had a slight edge but by f8 and past the two lenses performed almost identifcally in terms of sharpness. The Canon lens has a tiny bit more ‘snap’ (contrast) and a slightly cooler colour cast but otherwise the lenses performed essentially the same. The photo below compares center sharpness at f8 between the lenses.

Canon 300 f4L vs. Sigma 100-400 - center sharpness

When I compared edge sharpness between the two lenses I was surprised that the Sigma lens was just as sharp along the edges as the Canon prime. And the good news is neither lens showed the magenta fringing at the edges like I saw in the 70-200mm lens. I also compared the sharpness of the Canon 300mm lens coupled with a Canon 1.4x converter to give me 420mm. I zoomed the Sigma out to 400mm and compared the sharpness of the two lenses. The Canon lens with the 1.4x converter could not match the sharpness of the Sigma zoom at any aperture whether in the center or along the edges. Below is a photo showing center sharpness at f8 for both lenses.

Canon 300mm F4L with a 1.4x converter vs. Sigma 120-400

The Sigma 120-400 can easily compete with Canon’s 70-200 f4L and 300mm F4L lens in terms of sharpness. The other two lenses have a bit of a speed advantage with a wide aperture of f4 (useful for sports and wildlife shooting) but for landscape purposes, the Sigma is way more flexible combining a huge zoom range with excellent overall sharpness.

Canon 100-400 f4.5-5.6 vs. Sigma 120-400 f4.5-5.6

Ok, this is the shootout that I was really interested in. Are the two lenses comparable? I tested the lenses at 120, 150, 200, 300, and 400mm at all apertures. In the images below I present the results at f8 where both lenses tended to perform the best.

At the 120 and 150mm the Sigma was superior because it had much better edge sharpness and very little colour fringing. The Canon lens has noticable fringes in contrasty areas along the edge of the frame (see photo below). Also note that the Canon has a much cooler colour cast than the Sigma lens.

Canon 100-400 and Sigma 120-400 at 120mm

At 200mm sharpness evens out between the two lens with similar center sharpness and a a slight nod to the Sigma for better edge sharpness (see below)

Canon 100-400 vs Sigma 120-400 at 200mm

At 300mm the Canon is sharper in the center but the Sigma is sharper at the edges of the frame (see photo below) so I would call the test a draw.

Canon 100-400 vs. Sigma 120-400 at 300mm

At 400mm the Canon is clearly superior both in the center and at the edges (see below)

Canon 100-400 vs. Sigma 120-400 at 400mm

But in my other sharpness tests with the two lenses I found that the Sigma Lens gave equal or better results than the Canon at 400mm. I think the reasons for the differences are dependant on the ability of the camera or the user to get precise focus. I used Live View at 10x to focus all lenses but at 400mm I noticed that the Canon lens ‘snapped’ into focus more obviously using Live View than did the Sigma when both were racked out to 400mm. The photo of the fence below shows that the Sigma can give great results at 400mm if perfect focus is achieved

Test 2 of Canon 100-400 vs. Sigma 120-400 at 400mm

As a general conclusion the two lenses are pretty similar with the Sigma performing better at the wider end of the zoom range and the Canon performing better at the longest focal lengths or at least the Canon was easier to focus precisely at longer focal lengths. In the middle ranges of 200 and 300mm the lenses are pretty evenly matched. The Canon has a little less lens vignette but the Sigma has less colour fringing on the edges. The Sigma lens is a little warmer in colour cast than the Canon lens.

Autofocus and Image Stabilization

I did some autofocus testing with the both lenses on static and moving subjects and I really could not see any difference in lens performance between the Canon 100-400 or the Sigma 120-400. Both seemed zippy and locked focus pretty well. I had the same amount of keepers from both lenses when using auto-focus. But I am not an action/sports shooter so my tests were not rigourous. As well, in my casual tests of how well the Image Stabilization (Canon) and Optical Stabilization (Sigma) worked for handheld shots, both lenses gave me similar results. I was happy with the stabilization system in both lenses used and I could manage hand-held shots about two shutter speeds below what is recommended for non stabilized lenses.

Conclusion

As a landscape lens I really liked the Sigma 120-400 lens for its great range and convenience. It gave me as good as the results I currently get from my  70-200 and my 300mm Canon lenses and better results at 400mm than I get with my 300mm coupled with a 1.4x converter. So now I can take just one zoom lens and leave the two other lenses and the converter behind. If I were a wildlife shooter I might stick with the two Canon lenses for the extra speed that f4 gives me.

When it comes to the Canon 100-400mm and the Sigma 120-400mm it really is a matter of weighing benefits and costs. The Canon lens performs better (or is easier to focus precisely) at 400mm and it vignettes less at wide apertures. On the other hand it has the push-pull dust-sucking zoom and chromatic aberations at wider focal lengths and costs significantly more than the Sigma zoom (about $1750 new in Canada). The Sigma performs better than the Canon zoom at focal lengths 200mm or less with little or no fringing and better edge sharpness. At 300mm the lenses are eqaully matched but sharpness (or ability to get sharply-focused images) falls off a bit at 400mm with the Sigma. The Sigma is a bargain at $1000 Can.

Personally, I would buy the Sigma lens over the Canon 100-400 zoom simply because I can not see much in the way of benefits or performance for me as a landscape shooter with the Canon over the Sigma. And $750 in savings is the benefit I get from my choice.

©Darwin Wiggett - Sigma 120-400mm lens at 273mm

I have read mixed reviews about both the Canon 100-400mm and the Sigma 120-400mm lenses in terms of sharpness. Whether this is a quality control issue with the manufacturers or testing differences among reviewers is hard to dissect. I do know that many photographers use too flimsy a tripod and have poor technique (center post up, no mirror lock-up, no cable release) when using telephoto lenses and so maybe some of the sharpness issues are a result of user error. When using proper techique both the Canon 100-400 and the Sigma 120-400mm lenses can deliver professional results. I would not hesitate to use either lens.