Here is the difference between f stops and t stops. Basically, the f stop is
the mathenatical rating, whilst t stop is the actual rating. A 100mm lnes at
f4 will let through more light than a zoom at 100mm at f4 due to the
internal elements.
The front element of the Zuiko 500mm must be at least 500/8mm, or 62.5 mm.
How much actual light actually makes it through to the camera is the t stop.
Foxy
----- Original Message -----
Moose asked:
And how does that work with a cadioptric lens? I did some measurements
of mirror lenses and found that the 0f total aperture taken up by the
secondary mirror mount varies quite a bit, which might affect this
resolution thing, although it always seems to be properly subracted in
calculating the effective f-stop.
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