Acer V axes:
somewhere along the line i picked up that under macro, there is some light
lost...how do i go about calculating aperture for a given GN for a certain
mag ratio? Also, wil the T32 illuminate a subject if under min focus w/
50/3.5?
My rough understanding is that every lens, macros included, behave one of
two ways at minimum focus:
1. Focal length remains the same while effective aperture is reduced;
2. Effective aperture remains the same while focal length is reduced.
I've been able to observe the former by aiming a lens at a known, unvarying
light source and taking TTL meter readings at maximum and minimum focus.
Sure enough, some light loss was noted with some lenses.
I'm not sure of a simple way to measure the second. Any ideas?
---
Lex
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