Sell the R5 and get an R7 and R? Crazy?

User1303423862 wrote:

Sittatunga wrote:

mraifman wrote:

... For my bird photography, I find myself always using crop mode on the R5 and also wishing for more subject differentiation and nicer blurred backgrounds.

If you're always cropping your shots a lot, subject differentiation and nice blurred backgrounds are a function of the size of your lens aperture, not the size of the sensor. If the distances are the same and the focal length and aperture are constant, the geometry doesn't change, so the subject differentiation and background blur won't change, whatever the crop. You need a bigger aperture (in mm, not f/ number) to improve those things.

A bigger aperture only makes a difference if the sensor fully uses the projected image circle. Putting FF glass with a big aperture in front of a crop sensor won't help, unless you put a focal length reducer between the lens and the camera. But then you lose a lot of the extra reach the crop sensor provides, as well as some light in the optical path due to the extra glass.

A bigger aperture with a constant focal length and subject distance reduces the depth of field.  This blurs the background more and increases the subject differentiation, which is what mraifman wants.

The basic geometry doesn't alter no matter how or how much you crop, whether by using a smaller sensor than the lens will cover or by cropping in post processing. Teleconverters and focal reducers confuse the issue by changing the crop and changing both focal length and aperture, but these changes cancel each other out for what we were originally discussing unless their size is a significant proportion of the subject distance.  The format size a lens was designed for has absolutely no effect on depth of field for a constant sensor size.