Finally got the chance to appropriate a Canon 70-200 f/2.8 IS lens to run some comparison tests with my Sigma 70-200 f/2.8 and to finally check out first-hand the power of IS (Image Stabilization). And man, I wasn't disappointed.
First off, a quick physical comparison. Both lens are definitely not lightweights with the Sigma coming in at 7.2" long and 2.8 lbs and the Canon eclipsing that at 7.8" long and 3.24 lbs, almost half a pound heavier! Doesn't feel too different when you're holding just the lens in your hand but stick that on to your camera body along with a flash unit and you start feeling it after awhile. So using either of these lenses will definitely give you a nice upper body workout.
On to the pics...
First test shots were done mounted on my flimsy plastic tripod which was barely strong enough to hold these things. Indoor ambient light, no flash, ISO 800, hood on, shutter tripped using the Canon RC-1 wireless controller set at 2 seconds. IS was turned off on the Canon lens since it wasn't necessary for tripod shots. Pics shot in RAW and unedited except for resize and conversion to JPG. You can click on the pics below to see the larger versions.
The first set is at 70mm f/2.8. Difference between the 2 lenses seem to be minimal.
Sigma 70mm f/2.8, 1/30s
Canon 70mm f/2.8, 1/25s
Looking at the following 100% crops though, the Canon does seem to be a bit sharper.
Sigma 70mm f/2.8 Crop
Canon 70mm f/2.8 Crop
Again at f/5.6, the differences between the downsized images are still rather negligible:
Sigma 70mm f/5.6, 1/8s
But the crop at this aperture shows more vividly the sharpness of the Canon lens:
Sigma 70mm f/5.6 Crop
Canon 70mm f/5.6 Crop
And at f/11, pretty much the same thing going on:
Sigma 70mm f/11, 1/2s
Canon 70mm f/11, 3/5s
But this time, the Sigma crop actually looks as good as the Canon:
Sigma 70mm f/11 Crop
Canon 70mm f/11 Crop
Moving on to the other end of the spectrum, the following shots were taken at 200mm f/2.8. The Sigma looks decent at first. Until you check out the Canon which is just sparkling.
Sigma 200mm f/2.8, 1/30s
Canon 200mm f/2.8, 1/25s
The clarity of the Canon is better seen in the crop. Darn impressive really since it's wide open.
Sigma 200mm f/2.8 Crop
Canon 200mm f/2.8 Crop
Test shots taken at 200mm f/4 was pretty much the same as for f/2.8. The Canon coming in noticeably sharper. However, at f/5.6 the Sigma was beginning to kick it up a notch. The Canon was still sharper but the gap was closed quite a bit.
Sigma 200mm f/5.6, 1/8s
Canon 200mm f/5.6, 1/6s
Even the crop views are becoming very similar.
Sigma 200mm f/5.6 Crop
Canon 200mm f/5.6 Crop
At f/8, the samples look pretty much the same as with f/5.6 with the Sigma closing the gap maybe a little bit more. With the f/11 shots below, it's very very close but I think the Canon looks a bit sharper still but it's a tough call.
Sigma 200mm f/11, 1/2s
Canon 200mm f/11, 3/5s
The cropped versions show almost no difference and the Sigma even appears to have better color saturation.
Sigma 200mm f/11 Crop
Canon 200mm f/11 Crop
So for a lens that's less than half the price of the big shot Canon, the Sigma seems to be a pretty good contender. My copy can't compare to the Canon at either end of the focal length wide open but increase the stops by two and it's right there. If you're lucky you may be able to find a copy of the Sigma that's sharper wide open. The Sigma also seems to have a warmer tone to the pics that it takes. Autofocus-wise, both lens are quiet and fast with the Canon maybe performing a little quicker but not noticeably. Anyway, to be continued, this time with shots showing how IS just rocks my world.
