Hi captain.
I don't know too many imagers that work with magnification in mind. Normally its FOV that's more importants. (Sorry if you know all this already) But for a quick and dirty, rough and ready opproximation without the maths involved:- 35mm cameras equate to about a 50mm lense, so if you have 1500mm of tube FL then the mag will be 30 times. Now the bit converting it to size is the bit I get confused with. I think the magnification increase 1.6 to 50 times for canon chip in the same scope.
help out please knowledgeable brothers and sisters.