Originally posted by reh321 Many of us started off using 35mm cameras, so focal length carried certain information to us; after 20 years of using the full frame sensor known as a 35mm frame, we intuitively know what the field of view is for each lens focal length.
And many of us started with APS-C so we have an intuitive knowledge of what the field of view is for each lens focal length. And some started with MF or still use MF and intuitively know what the FOV is with that format unless it is a 645d or 645z which is cropped and has a completely different FOV. And what happens when I use my M42 Takumars on a Q? And was/is there not an APS-H format? Ron where are you?
Take a 50mm 645 lens. You can mount it on a film 645, a 645d, a 24x 36 camera, an APS-C camera, a Q and on a Q7 and get a different FOV, all with the same lens.
I think the entire photographic world would be well served if everyone started to refer to lenses using the FOV rather than the focal length. But since focal length is a lens property independent of the sensor it is used on the only 'standard' is what is scribed on the lens. So we are stuck with "relative focal length" and mental calculations.