Hi I am new to SLR and have purchased a Canon XT and Tamron 28-75 lens and circular polarizer. I am getting ready to take a trip to Guatemala in search of sailfish. I am hoping to get some jumping shots of these fast moving fish in bright sunlight. I suspect that I should shoot in Tv mode with the shutter speed as fast as possible. Is this correct? The camera will set all other factors for me, correct? How about the ISO setting? Do I set that myself before hand or will the camera handle that as well in Tv mode. For fast moving objects in bright light with alot of reflection, where should I set the ISO?
Also, I was considering getting a different lens for my trip, either buy a Canon 70-200 f/4L non-IS or renting a Canon 24-105 f/4L IS. Would either of these be better for what I am trying to accomplish? Will the IS help in a rocking boat? I am nervous that I will not be able to get the money shot of the angler pulling the fish up on the gunnel of the boat with the 70-200 lens and I do not want to be constantly changing lens out on the ocean. Or should I just stick with the Tamron? Also should I set the ISO differently for this type of shot? I am real confused about the ISO setting and how that works. Any help would be greatly appreciated. Thank you.
