On Fri, 29 Oct 1999 PCACala@xxxxxxx wrote:
:Kurt just posted a finding that the 90mm f/2 Zuiko Macro transmits less light
:than a 100mm f/2 Zuiko. I just thought I'd caution the engineer-types that
:the close-focus aberration correction in certain Zuiko lenses will change the
:effective focal length when close focused. Internal focusing does the same
:thing. For example, the 50mm f/2 Zuiko is actually 40mm at 1:2 magnification.
: Thus T/stop calculations ought to include this factor to be precise.
Uh, since the f/length is now less, with the same diameter lens opening,
shouldn't the effective aperture be numerically smaller (that, is a faster
lens)?
/Acer "steppenwolf" Victoria
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