If the cast represents Jeff's "broken" man parts, then the super-size telephoto lens is what he uses to compensate. It's the only way he can feel useful and powerful. Mere looking isn't enough—he lifts up this enormous camera lens to see even more closely. According to IMDb, the lens is a 400mm prime telephoto, whose magnification (we'll take their word for it) would make it almost impossible to use without a tripod. (Source) That's some pretty serious psychological over-compensation. Jeff's camera lens represents his work and his livelihood, everything that, back in the 1950s, made a man a man.

No wonder he needs that giant lens.