I think that you use your lense behind a dome , do you add diopters ??
Hi Dominique,
I have always used the lens with dioptres. I actually started off using a Canon 500D, but actually find better corner sharpness at the wide end with a cheaper, single element dioptre.
I was disappointed in the corner sharpness of my 17-70 (non HSM) at the wide end. I see that a couple of your pictures above suffer from the same. Is this normal for this lens? I was using mine behind a S&S Optical Dome (6in/15cm) and thinking about purchasing the larger NX Dome to hopefully resolving the issue.
Hi Pat,
Several of those images are taken behind a 4" dome. With such a tiny dome and a rectilinear lens, then yes, the corners loose a bit - particularly when very close. But with the large dome, 8", it is fine with the dioptre, which is what most of the other of those shots are taken with (sharks, not angel, + turtle). The rhinopias and seadragon were both taken with the small dome and 500D - see comments above - too.
I use the two domes with this lens depending on what I want to achieve. The small dome allows me much closer focus and much better quality of lighting at this close focus distance. The big dome gives better corners.
I tend to use this lens for creature portraits - so a bit of loss of softness in the corners does not really distract from the image. Of course if they were wide angle scenics and the corners weren't sharp - then they would distract from the image and that would be bad.
Alex