>>3153559> It would be nice for a company to standardise 'field of view' into a measurement which could traverse sensor sizes....except that a lens can be used on multiple sensor sizes.
I've got a Mamiya 80mm f/1.9. It's a pretty sweet lens, and can cover a 645-sized slice of film. I have an EF adapter for it, so I can use it on
1. The Mamiya it was designed for, where it's a normal
2. My 1.0x crop 5D (or any of my film Canons), where it's a short telephoto
3. A 1.3x crop 1D-series camera, if I owned one
4. I've actually got an EF to E adapter, so I can mount it on my 1.5x crop Sony
5. My 1.6x crop Canon 70D
6. I could theoretically buy myself a μ4/3 body and adapter and mount it on a 2x crop sensor
7. Hell, I could buy a Nikon 1-series and adapter and rock a 2.7x crop
8. If we're being really insane, the Pentax Q exists in the world, in two sensor sizes, for a 4.6x or 5.6x crop factor.
So, which field of view do we label that 80mm with?
Granted, it's unlikely that a lot of people are going to be mounting Mamiya 645 lenses on a Pentax Q with 1/2.3" sensor, but the case of mounting full frame lenses on crop cameras happens all the damn time, and a lot of those lenses were made and their markings designed before APS *film* was a thing, much less APS-C-sized *sensors*.
So, what do we do?
Just label lenses with the focal lengths they are, and take five minutes to familiarize yourself with what length means wide, normal, and tele on your sensor size of choice.
