A few years ago now I had a D3100 and Sigma 70-200 f2.8 and managed to get a number of what I thought were nice sharp shots Mario paying attention by Chris Thomas, on Flickr Now I have an 80d, and 24-105mm f4L and don't seem to get the same level of shots. Now I appreciate there is an added layer of difficulty as the fish is in water, and I've not shown my best shot. Using flash on the fish pics too. Torazo sample by Chris Thomas, on Flickr Is there anything I need to do such as calibrating the lens and camera? Any other tips?