a) For telecentric lenses this is
the ratio of image size to object size
b) For entocentric lenses this is the ratio of image size to object size at a given distance.
If you want to map an obbject of 10mm diameter to s Sensor with 1/3″ (= 6mm diagonal!), you need a magnification of 6/10 = 0.6x
With a 1/2 “Sensor (8mm diagonal), a distance of 500mm and an object cutout of 16mm diagonal, the magnification is 8/16 = 0.5.
Doubling the distance (to 1000mm) allows the lens to see about twice as much (32mm ). As a result, a magnification of 8/32 = 0:25 results.
In particular, the magnification at infinity is zero!
Each entocentric lens achieves each magnification (if it can be used beyond the MOD)! .. We just have to choose the right distance between the object and the camera.
The Problem is however, that (for entocentric lenses) with the distance to the object, also the perspective changes. Telecentric lenses keep the perspective!
Typical high magnifications in microscope imaging end at 100x, where magnifications above 40x usually need immersion, say, the lens is used in oil!.
When you read about higher magnifications like 200x and higher, there’s an excellent chance that the size of the monitor is also included!