Semantics aside, what is the angle of view when using an 80mm MF lens on a FF DSLR? Would the resultant framing be equivalent to using a Canon 50mm EF mount lens?
ersatz wrote:
Semantics aside, what is the angle of view when using an 80mm MF lens on a FF DSLR? Would the resultant framing be equivalent to using a Canon 50mm EF mount lens?
Since full frame is smaller than MF, I think it's vice versa. 80mm MF presumably has an angle of View on FF like a 138mm FF lens. I calculated a format factor of 1,73 if using 6X45 on FF. That means, a a 80mm lens always has 80mm focal length, but it has an angle of view on MF that is wider. If you're used to FF, then nothing changes.
ersatz wrote:
Semantics aside, what is the angle of view when using an 80mm MF lens on a FF DSLR? Would the resultant framing be equivalent to using a Canon 50mm EF mount lens?
The angle of view when using an 80mm MF lens on a FF DSLR is the same as when using an 80mm EF mount lens.
ersatz wrote:
Semantics aside, what is the angle of view when using an 80mm MF lens on a FF DSLR? Would the resultant framing be equivalent to using a Canon 50mm EF mount lens?
The answer is in this thread, probably multiple times. The answer is no. The focal length stays the same regardless of the size of the sensor. A 80mm on MF is equivalent to a 50mm on FF in angle of view ONLY on its NATIVE FORMAT, because the recording medium is larger.
The image circle of the MF lens needs to be bigger in order to project a large enough image on the medium format film/sensor, which is why those lenses are more bulky than 135 format (FF) lenses. A FF sensor only captures (crops) the central portion of a MF lens, which is why a MF lens doesn't have a wider angle of view than a FF lens.
Edit: H.Lux is incorrect. Focal length is not related to the size of the recording medium. Crop factor influences the field of view, not the focal length.
AhamB wrote:
edit: H.Lux is incorrect. Focal length is not related to the size of the recording medium. Crop factor influences the field of view, not the focal length.
That what I have written.
Focal length is a characteristic of the lens.
The question was about the angle of view, however. That one is wider on MF. However, if you use a MF lens on FF, the angle of view is the same as if you used a FF lens of the same focal length.
(did I explain now more clearly?)
RustyBug wrote:
The angle of view and focal length remain the same irrespective of format ... the field of view varies with the format for a given focal length.
That's contradictionary to how wikipedia defines the angle of view:
In photography, angle of view describes the angular extent of a given scene that is imaged by a camera. It is used interchangeably with the more general term field of view. It is important to distinguish the angle of view from the angle of coverage, which describes the angle of projection by the lens onto the focal plane. For most cameras, it may be assumed that the image circle produced by the lens is large enough to cover the film or sensor completely.[1] If the angle of view exceeds the angle of coverage, however, then vignetting will be present in the resulting photograph....Show more →
As English is not my mother tongue I cannot decide which definition of AOV is correct: How do you call the angle of arrival of the incoming ray that lightens the corner pixels of the sensor?
@Rusty: I thought field of view was the width of the scene that is captured at a certain distance. For binoculars or spotting scopes the FOV is often specified as xxx metres at 1000m distance (in Europe anyway).
@H.Lux: You said "80mm MF presumably has an angle of View on FF like a 138mm FF lens." which is incorrect. The AoV of a 80mm MF lens on a FF camera is exactly the same as a FF 80mm lens on that same camera. Maybe you calculated the equivalent of 80mm on FF for MF, but that is not what mMontag was asking about.
my bad ... I was referring to angle of projection which never changes.
The binocular example makes a good point to the fact that FOV (i.e. framing) is subject distance relative. This is where the whole equivalent FL falls apart ... it requires a different subject distance to achieve a similar FOV ... and that subject distance has a significant impact on DOF, etc., so it really NEVER is equivalent FL, but rather equivalent FOV.
AhamB wrote:
Maybe you calculated the equivalent of 80mm on FF for MF, but that is not what mMontag was asking about.
Good point.
I think we all agree now.
