Originally posted by photoptimist aperture for similar depth-of-field or hyperfocal distance: use the crop factor
I have such a terrible time wrapping my head around any of this. I've previously only used aps-c sensors so I didn't care what 'equivalence' even meant, since I just used the one format.
but... I've been shooting 35mm and some 120 film and the topic is a bit more interesting now...
It seems to me that the quality of light leaving the rear element towards the sensor would be the exact same no matter what format it's mounted on.
All that changes is the amount of 2D surface area captured from a lenses potential image circle.
For instance, the quality of brightness does not change between formats.
So why is it that an image quality such as depth-of-field change between formats?
Wouldn't the depth of field have been 'decided' at the time the light left the lens?
Yet I've seen images where people display the bokeh and field differences and equivalences.
I just don't get it haha