I always see the reflection on the camera sensor having a little chamfer:
But the plane in front of the sensor does not have this chamfer, the reflection should be a right angle if it's a mirror:
Where does this chamfer come from?
Photography Stack Exchange is a question and answer site for professional, enthusiast and amateur photographers. It only takes a minute to sign up.
Sign up to join this communityI always see the reflection on the camera sensor having a little chamfer:
But the plane in front of the sensor does not have this chamfer, the reflection should be a right angle if it's a mirror:
Where does this chamfer come from?
It is a shadow of the lens mount due the lighting angle... this image makes it more apparent:
Also note that your blue line is incorrect and the sensor plane begins at (nearer) the red line... the black between those two lines is also shadow.
The camera lens projects an image of the outside world on the surface of the light sensitive sensor (or film). For aesthetics, we want this image recorded with a perfectly straight boarder with perfect corners that meet as right angles. Same is true for negative carriers used in an enlarger. From a machining standpoint, we need a knife edge to make this happen. The campher is a neat way to make a knife edge.