Iím a fundus photographer. Film backs in this field is before my time, but the cameras we use today are adapted to digital. Aside from color photo (slide film) our specialty is angiography which requires a rapid series of photos taken as we object dye into the arm (say one per second for one minute straight.)
Iím used to topcon fundus cameras but zeiss is popular. Zeiss makes all sorts of ophthalmic devices.
Interesting an m4 would be put into that situation, but I guess why not?
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