28mm on reversal ring HELP PLEASE
Maybe I am only confusing myself but..
I am doing some macro using my 28 mm on a reversal ring thus magnifying about 2.5X. Metering is a PITA because of false light through the wievfinder so Im in trouble each time I preparing the exposure. Lets keep the PK13 I'm mounting it on at times out of the question for now
I find The meter is fooled to underexpose even when the wievfinder is blacked out (feature on F90X). I would like to use a handheld meter instead.
So Whats the "focallenght" of a reversed lens.
Does "(effective aperture) = (set aperture)* (1 + [mag ratio])" still apply
I do think so myself but when calculating magnification I need the focallenght and extension. So is a reversed 28mm still 28mm to the camera/film/meter ?
If the focallenght is not 28mm when reversed what about the F-stops ?