RJM wrote:
Sony full frame designation is FE for their full frame lenses.
The E mount crop sensor lenses (from APS-C cameras) will fit the full frame Sony camera and work well.
My question is that will, say for example, a 16mm E mount lens be 16mm on Full frame or will it be 24mm (in full frame equivalent) when fitted on full frame camera?
RJM wrote:
Thanks for the replies.
I guessed it would probably be the same as marked on the lens, eg 16mm.
I can't see any vignetting but then Sony advertise that their E mount lenses will fully work with full frame mount (FE).
It can be confusing when everything is compared with full frame (as though it's the be all and end all) when there is also MEDIUM FORMAT which is even bigger!
Why call it MEDIUM when FULL FRAME is smaller?????
They do make it hard for us!!!!!!!!!! :)
Thanks for the replies. br br I guessed it would ... (
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With all interchangeable lenses, the focal length is the focal length, it does not matter what camera they are mounted on. With digital photography, this includes
1. 1"/CX (Nikon 1), 2.7x
2. micro 4/3, 2x
3. APS-C, 1.5x/1.6x
4. full frame, 1x
5. medium format, 0.7x
The focal length is a physical characteristic of the lens alone.
The thing which does depend on the sensor is the field of view. While we should talk about this in terms of angles, that seems to be more difficult, so we talk about "equivalent focal length".
As far as why we scale everything to the "full frame" sensor, that's easy: when digital interchangeable lens cameras were being developed, they are part of existing 35mm systems, the lenses were simply taken from the 35mm film cameras. Even today, a Nikon FX lens can be used on three different size sensors, FX (full frame), DX (APS-C), and CX, so it still makes sense for one of those to be the baseline.
Medium format lenses are generally not used on smaller sensor cameras, so they do not get used as baseline. There are also three "common" medium format sizes, 645, 6x6, and 6x7, so the medium format world doesn't have an internal standard to offer anyway. I think that 35mm is as close to a standard as the film world has ever had, best exemplified by the disaster that was APS. Maybe not "the be all and end all", but the closest thing to a king. :-)
Finally, to the question of why bother: yes, you can simply put a lens on and decide if you like how it looks. But if you actually want to
plan your shot, then having a way to know what to expect can help. If someone is only using one sensor size, then it makes sense for them to simply get used to what focal lengths mean what for that size. But if they are going between several sensor sizes (including 1/1.7" and 1/2.3" for compact or bridge cameras), it helps to have a common language. That has become the "effective focal length".