Some 18 years ago I think, using my new T32, I found that the recently
launched Zuiko 28mm F2.8 was darker @2.8 than my older 50mm F1.4 SC @2.8.
I remember having sent the Ektachromes to Olympus Japan, who returned them
together with some explanation I don't recall. Does this happen often?~
Always ;) f/stops are different than real stops, called t/stops.
The f-stop is a geometric relationship between focal length and effective
aperture and does not take into account light loss within a lens.
Each air to glass surface reflects some light. So real 'opening', called
t/stop is different than f/stop. This difference depends of lens construction
(number of elements, coatings used..) and usually is NOT given.
Only some companies, most notably Kiron, callibrated their
diaphragm scale in t/stops.
BTW, what do all the people in this list mean by bokeh ??
Read 'Good bokah, bad bokah' thread. Type 'Bokeh' into web searcher
(e.g. Google). then you will be enlighened ;)
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St.
(XS360 Diesel - Sampo Lappelil, ZliMC)
http://www.familyofman2.com
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