This Fall while visiting my favorite Ducking Hole to see if my favored Buffleheads were back from their Summer breeding ground, I spied a gent with a rather nice lens. He had a Canon 40D mounted on a Canon 500mm f/4L IS. He may have had a 1.4x teleconverter on it too, though I can't recall with certainty. He seemed to be having a very good time.
I looked down at my Canon 7D mounted on a lovely Canon 100-400 f/4.5-5.6L and was instantly overcome with lens envy. The gent with the 500mm lens was able to reach out a lot farther than I was able. And, there were birds out there that I really wanted to photograph. Of course. This is how addition works, right?
After selling off a stack of unused glass, I was able to find a nice Sigma 300-800mm EX HSM f/5.6 lens. It arrived in good shape and I wanted to test it.
So here is a wee test. I used images taken with a Canon 24-105L and Nikon 55mm f/3.5 Micro as control lenses. These are as sharp as sharp can be. I also shot the Canon 100-400L to see how good the Sigmonster stood up against my favorite bird lens.
By clicking here, you can see the full sized results. These are 100% crops from a Canon 7D. Since the 18mpixel sensor has such a strong anti-aliasing filter, I added 3 sharpen in the RAW tab in to DPP Tool menu. 3 seemed to be a nice balance between the very soft straight out of the camera thru DPP converted JPGs and obvious over-sharpening.
The Sigmonster is a very fine lens. However, focusing the Sigmonster at 800mm's was a real bear! I'm not convinced I have the test target in focus. Look at how the Nikon 55mm f/3.5 performed at f/5.6 with the same two dollar bill details. The Nikkor was MUCH easier to focus than the Sigmonster. Still, one lesson may be to stop the Sigma down at least one stop when shooting at 800mm. It might be unacceptably soft wide open at that focal length.
The Sigmonster appears to out-perform the Canon 100-400L at 300mm and 400mm, but just barely. The 100-400 is a nice lens and holds it's own against the Canon 24-105L and Nikon Micro Nikkor. Though the shorter Canon zoom and the Nikon prime appear ever so slightly sharper to me, it's nothing that a little sharping with DPP can't clean up.
Bottom line, for me the combination of the Canon 100-400L and Sigma 300-800mm EX HSM will be wonderful to chase birds with. Both are sharp. Both focus nice and quick. Both respond well to the 7D's speed of handling and the DPP conversions to jpg.