I was pretty happy with the results and will be keeping the lens for use with my 5DIII. The lens is definitely sharper at f/11 than it is at f/8. There are probably three reasons why the full frame camera gets better results with this lens than the smaller sensor cameras I've used it with.
- The sensor in the 5DIII is simply bigger, newer and better, and captures better files, as it should.
- The smaller apertures that get good results from this lens are less likely to result in softening from diffraction on a full frame camera as the pixel size is larger.
- The 5DIII has much cleaner files (less noise) at the higher ISO settings that enable smaller apertures.
Both adults were around while I was there today. Here is a shot of one in the air and then after it landed on a branch near the nest. The second shot is a non-cropped image at 500mm with the full frame body.
After about 45 minutes of waiting for them both to be on the nest for a shift change, I gave up and headed out. Of course, as I walked down the trail what I had been waiting for happened. This is what I caught, from a bad vantage point.