Fullframe is equivilant to a 35mm film, Will Give you a much better image and more colour depth. Full frame kicks ass,

Crop sensor is basically that imagine a full sized sensor and you chops all the edges off all the way around

couple shots i have done with the sigma 12-24
Dont mind the two room shots being bit dark was trying to get the light right still playing lol but shows u the width anyway with out lines looking like fish eye.