The BigmOS: A Review Of Sigma’s Stabilized 50-500mm LensGear Talk
BorrowLenses.com has carried the non-stablized version of the Sigma 50-500 for some time now. That lens, nicknamed the “Bigma” has been something of a cult favorite, despite its many failings. We recently introduced what I consider to be its older, more grown-up sibling, the Sigma 50-500mm lens with Optical Stablization, to our inventory as well. I took the Canon version of this lens, nicknamed the “BigmOS”, out for a spin to put it through a few paces.
Let’s get this out of the way immediately: when you use a lens like the Sigma 50–500mm f/4.5–6.3 APO DG OS HSM (there’s a mouthful for you), you really do have to keep your expectations in check. If you can remember that any lens with a 10x zoom factor is going to compromise quality and adjust the bar accordingly, you’ll walk away with some pretty decent images.
On the surface, the idea of having a lens that goes from a pretty standard 50mm focal length all the way out to 500mm might seem like a wonderful thing. Why on earth would you carry that big, heavy, 500mm f/4 lens out to your first wildlife photography trip when you can have this thing and hand-hold it, at least for a while?
That’s a question we get asked quite often with this lens, and the answer to it can be summed up in one word: quality.
When you have a lens with as many moving lens elements (the individual pieces of glass inside the lens’ barrel), you are going to see a fair amount of quality loss. Prime lenses like the 500mm f/4 from Canon only have to address quality concerns at a single focal length, so the optics inside are a lot simpler than those in a zoom lens.
The longer the range of the zoom, the more complex the optics and mechanics have to be. With these “super-zoom” lenses, even the smallest of imperfections can get magnified and result in noticeable quality loss.
So, now that I’ve laid out the issues with this category of lenses, how did the Sigma perform? Let’s take a look.
In comparison to the big super-telephotos from Canon and Nikon, the Sigma is practically svelte. That’s not to say that it’s lightweight, however; at over 4 lbs, this is not a light lens. It does, however, manage to pack a lot of glass and tech into a barrel that’s hand-holdable – at least, for a little while.
There’s a “foot” that you can attach a tripod mounting plate or a monopod to, which is handy. I never bothered to put it on a mounted platform, though; since this lens is Optically Stabilized, I wanted to see just what it was capable of while shooting hand-held. The foot was handy, however, to carry the lens with the camera attached as I walked around with it.
The barrel is coated in a matte finish, portions of which feel almost a bit soft to the touch. It should resist dings and bumps fairly well (though that doesn’t mean that the innards will be fine if you go bumping the barrel on hard objects). Sigma appears to have improved the build quality of this lens over that of its non-stabilized sibling, as it feels more solid, less plasticky.
Zooming the lens takes a bit of an effort – you certainly won’t be zooming in and out in a jiffy with this thing. The inner barrel extends out quite a bit as you move the lens to 500mm, about doubling its length. Having a tripod or some other platform to stabilize it will definitely prove to useful, as the lens can get very front-heavy.
The lens also includes a hybrid hood of sorts; APS-C cameras like the Nikon D7000 or the Canon 7D (the Sigma is available in both mounts) can make use of a hood extender, since this is essentially an 80–800mm lens on a Canon 7D and below, and a 75–750mm lens on a D300s and below. That extender will cause heavy vignetting if you use it on a full-frame camera like the D3s or the 1D Mark IV, and I suggest just leaving it off, since I really don’t see the point of it.
While testing this lens, I noted that this lens can perform surprisingly well, given ideal conditions.
Focusing is reasonably quick on it, though I still prefer the Canon 400mm f/5.6L lens’ focusing capabilities. Tracking flying birds across marshland, the lens does tend to loose focus and skip to foreground or background objects, but I’m willing to acquiesce that I may just be more demanding, being used to all the nice toys at BorrowLenses.
The Optical Stabilization does work, and does so pretty well. I was able to handhold shots at shutter speeds as low as 1/60 at 500mm. That may not seem like much, given that I can shoot as slow as 1/15 with some lenses (the Canon 100mm L Macro comes to mind), but this is one honking large lens, and 1/60 is, I think, pretty darn good. That’s about 3 stops slower than I could with OS turned off.
Image quality does suffer; this thing has 22 lens elements, after all, and that’s a lot of glass for light to pass through cleanly. Compare that to the 400mm f/5.6L’s 7 elements and you start to realize one of the reasons why primes are so much sharper than zooms.
Despite that, however, Sigma has managed to wrangle some very nice pieces of glass into this lens. There are four SLD (Special Low Dispersion) glass elements that help boost image sharpness and color, and I have to admit that, compared to this lens’ older sibling, this thing was surprisingly sharp.
At a max aperture of f/6.3, this lens isn’t very “fast” in terms of light-gathering capability. Compared to lenses like Canon’s 400mm f/5.6, that extra 1/3 stop might not seem like a big deal. However, since this lens isn’t as sharp as the Canon, if you have to do a bunch of noise reduction in post-production, you’re likely to see substantial loss of detail.
I expected, there is a good amount of distortion and chromatic aberration, especially at the telephoto end. Lightroom users will appreciate the fact that Adobe has included a lens profile to correct for this for the most part, so it becomes less of an issue.
When reviewing this lens, I noted on my Google+ page that “If you throw enough light at this lens, add in a healthy dose of post-processing (mostly distortion and chroma correction, with a chunk of noise reduction), and mix in some luck, you can actually come away with decent images.” I stand by that assessment.
For the rental price, I’d go with a Canon 400mm f/5.6L over this lens any day. That being said, however, I did like this lens.
Yeah, I know. After telling you how many ways this lens doesn’t do well in comparison to my obvious favorite, the 400mm f/5.6L, now I go and say that I like this lens.
Here’s why: for what it is – a super-zoom with almost two dozen glass elements, made by a third party company – the Sigma 50–500mm OS actually did really well.
The benefit of a super-zoom can’t be dismissed. For a backpacking photographer traveling to remote areas without much support, this lens might just do the trick for a lot of different types of photography.
A 400mm f/5.6 prime is nice, but let’s face it; it’s not going to be handy for anything except getting in close to your subject. When space is a concern and you need a do-it-all lens with a longer reach than your typical kit zooms (or even a zoom like the 28–300mm lenses from Canon and Nikon), then frankly, this is as good as it gets.
I’d rent it again, along with a Canon 7D; together, I’ve got the reach of an 800mm f/6.3 lens, and that’s not half-bad.
And, as you can see from the attached images, I did get some nice stuff.
Bird Images by Sohail Mamdani. Copyright © 2012, Sohail Mamdani. All Rights Reserved.
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