paul_j_c2000
Well-known member
Hi i am looking for a l series lens for my 10d iam torn between the 500 f4 is and a 400 f2.8 is, my main use being bird and wildlife, although the 500 will give me the distance,iam thinking the 400 being a faster lens will give me more choice of acceptable shots and if i needed that bit extra i could add a 1.4 or 2 x converter .would this setup be as good optically as the 500 f4 i dont no much about converters do you lose sharpness and quality,can you use both at the same time do all features work with the 10d ,af , is ,etc any help please paul