I'm about to leave for a trip to Abu Dabbab in Egypt. With some luck we should be able to photograph sharks (Elphinstone) and dolphins (Sataya dolphin reef). Which lenses are the best option for those subjects? I normally use a Tokina 10-17 for wide-angle, but I wonder if that's too wide? I have absolutely no idea how close you can get. Should I add a 1.4 teleconverter for some extra reach, or is the range of Tokina alone sufficient?
I also have a Sigma 10-20 which I bought very recently. But I wasn't able to get a zoom ring in time, so I can only used at a fixed angle. I also didn't have a chance to try it in the water yet. So I'm not sure if it's worth taking with me.