Leonard Migliore

Humans are primates.

For distant objects, doesn't a 100mm lens produce an image twice the size of one generated by a 50mm lens? Isn't that why we use telephotos?

Most of our problems are due to crazed primates.

I had no issue with the 12MP of my D300. I only got a 24 MP D750 for its substantially better high ISO performance. But I could do reasonably big prints from the D300 as long as I didn't crop much. ...

The exposure will be the same. That's what f/numbers are for. The entrance pupil of the 100mm lens is twice the diameter of the entrance pupil of the 50mm lens. This means it has four times the ...

Sometimes it's hard to tell. That's wrong because it doesn't take into account the distance between the principal planes.

I believe that walking a test chart out to infinity is not practical. Also, what would that tell you about focal length?

What do the parenthetical numbers signify?

But mirrorless cameras should be cheaper; they have fewer moving parts and internal optics. I realize they're trying to recoup development costs but the manufacturing cost of a Z7 should be much ...

That was what I attempted to point out. Unless you understand the mathematics, it's nothing but received wisdom; it doesn't clarify anything.

The problem is that you're attempting to understand optical concepts without going to the effort of understanding the principles behind them. Focal length is actually something quite abstruse. I ...

Well, I feel cheated if I don't get everything I can out of the image. So with a high-rez camera, I'm going to try to get the picture sharper by, say, using a shorter exposure time. It lets me ...

You will need a neutral density (ND) filter to allow long exposure times with proper exposure. If you want, say, a 1 second exposure in daylight at f/8 and ISO 100 you need an 8-stop filter. Such ...

Well, if you put an extension tube or a close-up lens on a camera lens, you have to move closer to be in focus. That's the whole point of those devices. Note that if you move closer to an object ...

How are you supposed to use that 90mm Elcan on a rangefinder camera? You can't see out the RF window because the lens blocks it. And you'd really want to get the focus right on that thing.

By "aperture" one may mean the relative aperture (like f/2.8), the entrance pupil diameter or the physical size of the opening in the diaphragm. I was trying to remove the possible ambiguity in ...

As I read the instruction sheet, it seems to me that the adapter cuts off any light above f/4. But it doesn't change the aperture from what you set. For example, if your exposure was 1/250 at f/8 ...

Yes. Front-mounted converters do not change the f/stop. Now, they usually degrade the image, distort and vignette but you still have the same f/stop.

Maybe it can be defined like that but it would not be correct. As a counterexample, I have a 20mm focal length lens for my Nikon DSLR. You can't have any glass closer than 38mm from the sensor or ...

you probably mean a 20mm f/2.8 Yes. Front-mounted converters do not change the f/stop.