I am looking at expanding my lens for my EOS Rebelt3i. I have a 18-55mm, just bought a 50mm F/1.8 lens. and now I am looking at either a 135mm or a 75-300. There is also a "CPC AUTO ZOOM 75-200mm MACRO CCT CAMERA LENS 1:45 C/FD Mount MC Canon" lens for sale but not exactly sure what that is? I am doing pet photography and am mainly looking for a lens for outside action shots with blurred backgrounds. If someone could help explain to my what the last lens is and what is better a 135mm or the 75-300. Is the last one the same thing as a 75-300mm except for it only goes to 200? Thank you for your help! I have until tomorrow to figure this out.