Wow, it's really long, isn't it?
And what's more, it gets longer as the focal length extends. So, you realise the shot isn't tight enough, pull the 35, which has a 2'8" MOD, and put on the 50. Which has a 3'6" MOD. So you move back, and you realise you've achieved... er, more or less the same frame. So you grab the 70. Oh, dear. Four and a bit feet.
Unfortunately, I didn't have any diopters of a suitable diameter, but I'd have been a bit alarmed at the prospect of even more distortion and softness.