>>4160445He means the other end of the lens, dingus. Larger objective lenses gather more light. This is a basic principle of optics.
>>4160437OP, there already exist several super fast 50mm lenses, f/1.2 and beyond.
The reason you don’t see like, f0.5 lenses is because big objective lenses like that need a long focal length for good optical quality. If you were to try and use one that could work in a shorter focal length, you would need a more convex lens that more aggressively refracts light over a shorter distance. This comes at the expense of optical quality and would I introduce tons of chromatic aberration and other problems. You could correct those with more internal lenses, but then you’re robbing the light that you worked so hard to get.
As far as wide angle lenses, you would need an absurdly large objective to get close to the f/1.4 or faster range, and it gets logarithmically worse tbe wider you go. That’s because thr f-stop is the appparent diameter of the entrance pupil when viewed from the front of the lens. Wide angle lenses naturally make that pupil smaller, ergo it’s a self-limiting design. Retrofocus wide angles are also easily the most complex optical formula, so we just aren’t there yet with technology.
