lenses are circle. Sensors are rectangle. Would the resulting photo be skew out of proportion? What about oval shape lenses

Question

lenses are circle. Sensors are rectangle. Would the resulting photo be skew out of proportion? What about oval shape lenses

In: Engineering

Answer 1

The sensor might be a rectangle 24x36mm but the lens projects an image with a larger circle… at least 42mm but maybe even 50mm in diameter (it’s actually not exactly easy to measure as the edges of the image circle are very fuzzy and soft, but the inside sharp and bright area for “full frame” camera lens would be at least 42mm). The sensor only captures a rectangular area inside the image that is projected by the lens. This is why if you take the same lens and go from a 24x36mm “full frame” sensor to a 14x22mm “APS-C” sensor the image is more “telephoto” or “tighter” as the smaller sensor “crops into” or only captures a smaller area of the lens image.

Oval lenses would be weird and would either stretch the image like an anamorphic lens or make it focus weird (if you have an astigmatism your lenses actually have a slight cylindrical bow to them to correct the focus issues with astigmatism)… depends a bit on the specifics of how the lens is designed.