Just as a comparison, I took a few pictures with a few different lenses, and outlined them in the original 50mm image.. Consider the black borders "picture frames", and inside that border is the next image (border not included..) The lenses used were the Canon 50mm 1.4 USM, the Sigma 85mm 1.4, and the Tokina 50-135. 135 is pretty tight compared to 50! Not sure how much reach over your 50mm you need..
Also, not all same-focal-length-lenses are exactly the same focal lengths.. For all I know, the Sigma 85mm could be closer to 90mm, and the Canon 85mm closer to 80mm.. (It happens a lot... I DO know that my Sigma 120-300 at 120 falls between that 100 and 135 shot, so those are probably pretty close..)