Microscope interface selection

FMA and AMA are typically calculated and selected for magnification according to 18/20 mm intermediate image circle size.

Optical interfaces for major four brands are typically calculated for magnification according to 24 mm intermediate image circle size.

For example, if camera sensor is 2/3 inch (diagonal size 11 mm), you can choose 0.5X optical interface because 24×0.5=12 mm is already larger than the camera sensor diagonal size, so no vignetting will occur.