I learned years ago that the human eye is 55 mm; 58 mm. is possible, l guess. The first new camera I ever purchased was an Exacta VX with a 55 mm f-2 lens. That was in early 1952 in Wurzburg, Germany when I was in the Army then and there. I think there were many cameras in that era with 55 mm lenses and I think it was because it was the focal length of human eyes. You could look through the camera's viewfinder with one eye and see the same thing in the other open eye and the scene would not be different. The 55 mm answer was not from a photographer but from a scientist, I believe. Over my more than 70 years in photography I've subscribed to dozens of photo magazines and learned (and forgotten) much. This fact -- eyes are 55 mm focal length -- has stuck with me! -- Jim J.

I thought I read a long time ago that on a 35mm camera a normal 50mm lens is included because it’s pretty much WYSIWYG (What you see is what you get). But I know this is definitely not true when it comes to objects like the moon. Is it some sort of perspective trick, or because our Eyes and Mind can concentrate on a single object out of a whole seen that to our eyes 👀 the full moon 🌕 looks relatively large. But when shot with anything less than a 2-300mm it’s a very small circle.

I’ve been photographing since the early 70’s and shot professionally for 20 years. I’m also an amateur astronomer. This just came to mind while watching the almost total lunar eclipse last week. Then tonight I watched a video from an accomplished Amateur astronomer & YouTube monitizer who decided to go simple and capture the eclipse on a FX Canon camera with a 110 2.8 lens. The moon 🌚 was pretty small.

So to sum it up ⬆️ is there truth to a 50mm being generally what we see? And what MM on an FX or DX I have DX gives you the moon 🌝 as our eyes 👀/ brain 🧠 perceives it. Thanks 🙏 in advance. Dave in PA.

BTW I do realize there’s a difference especially to our eyes if the moon is at the horizon or at ZENITH.