01-02-2015, 12:28 AM
Perspective is not dependent on the field of view at all - it is dependent solely on the geometry between the entrance pupil of the lens and the object.
You may be thinking of f-theta distortion, which necessarily grows as the field of view widens. This is the type of distortion you see in lens evaluations - both barrel and pincushion are types of f-theta distortion. At about 120 degrees f-theta explodes 'inherently' (and I do mean explodes - it increases by almost 5%/degree at 120deg, 7%/degree at 122deg, 10% at 125deg...)
At about 90-95 degrees it may become noticeable, being on the order of magnitude of 1/2% per degree. This inherent increase in distortion is known as rectilinear distortion colloquially. It can be counteracted or removed through strong barrel distortion (this is why fisheyes do not have it, or have little of it) but then of course you have a fisheye lens.
That said, if you increase the focal length you do reduce the angle dependence. A format 5x larger than full-frame that uses a 100mm lens to replicate the look of a 20/21mm lens on FF would have a noticeable amount less...
You may be thinking of f-theta distortion, which necessarily grows as the field of view widens. This is the type of distortion you see in lens evaluations - both barrel and pincushion are types of f-theta distortion. At about 120 degrees f-theta explodes 'inherently' (and I do mean explodes - it increases by almost 5%/degree at 120deg, 7%/degree at 122deg, 10% at 125deg...)
At about 90-95 degrees it may become noticeable, being on the order of magnitude of 1/2% per degree. This inherent increase in distortion is known as rectilinear distortion colloquially. It can be counteracted or removed through strong barrel distortion (this is why fisheyes do not have it, or have little of it) but then of course you have a fisheye lens.
That said, if you increase the focal length you do reduce the angle dependence. A format 5x larger than full-frame that uses a 100mm lens to replicate the look of a 20/21mm lens on FF would have a noticeable amount less...