You're taking your photos from angles aren't you? Your photos won't turn out as sharp as they can be if you take your photo from an angle to the glass. You should take your photos perpendicular to the glass to get a sharp image. Even though to the naked eye looking at the glass from an angle may look fine, once you go into the 55mm area the distortion becomes a major problem.
I've noticed you have a lot of money. Go get yourself a good external flash. One that you can use wirelessly or with a wire. Go to
www.aquaticphotography.com for a lot of help!