ordvr

Hello All,

I've had my D300 about a year now, and I've primarily used my Sigma 17-70mm HSM underwater. I shoot it in an Aquatica housing, with the 8inch dome port, and dual DS125s, all in manual mode. The problem is that I simply cannot get a 'sharp' image. Above water the images are quite sharp, so I'm not sure what the problem is. Regardless of whether I shoot at the wide end or macro, I have a terrible time getting a sharp image. I've put three images (not cropped, just resized significantly and converted to JPG) at:

Sample pics showing sharpness problems

I'm not sure what the problem is. I shoot in manual mode, and generally shoot at f/16 or smaller apertures, 1/100 to 1/200 second. I've had about 75 dives with this camera, most with this lens and I'm just not happy with the results. I actually was able to take better pictures (crisper/sharper) with my old camera (also shot in manual mode).

I have some that are okay, but this next gallery (large pictures, not significantly resized) are the best of a couple thousand shot on a trip.

Socorro trip

So, does anyone know if this is typical of this lens? Do I need a diopter? Could it be a camera problem? Am I just in need of some serious instruction?

I really appreciate any insight anyone can give. I'm pretty frustrated.

Thank-you!
Greg Cooley