yeah for the not FF cameras you rather get the 35mm and not the 50mm.
(btw im talking about nikon but im almost sure its the same with canon...)
f/2.8 lenses are great for indoor photographs and fo course for taking photos of robots and matches.
Those who talked about 1600 ISO - i dont know what kind of camera you have, but you should have a really good camera if you can take 1600ISO pics without lots of noise
Last year taking photos with my Nikon D60 with the kit lens - 18-55mm f/3.5-5.6 with SB600 flash worked really great. A better lens will make the photography much easier and much more comfortable
