Originally posted by Michael Barkowski And then adjust your 50mm by the 0.85x magnification of the viewfinder and you get 42mm ... which is still quite long ... interesting experiment though.
? Is that what it is for the K100D/K200D? I have the K10D which is 95% viewfinder coverage. I was going to make a statement about that differential but didn't want to "muddy the waters".
To address some of the other points made to no particular one person, yes, it's the relation of closer objects to further away objects -- in how their relational sizes are "seen" thru the lens and affected by perspective from the lens's focal length being "wider" or "longer" than [ahem] "normal" -- that viewing a chair at an isometric angle is supposed to capture. Any significantly sized object relatively close to you can be the subject, or two objects with some space between them (isometric angle then not necessary). If you view say
a [one] short candle however, the effect won't be very noticeable if at all. One can do the same by snapping an eye-piece that has 1x magnification (I only have a 3x eye-piece) to the back of a zoom and zooming in & out with one eye while keeping the other naked eye on the same subject if one feels better about removing the camera's mirror box from the whole equation.
I just don't get the whole debate of "what
is the normals focal length that gives a perspective the same as the naked eye to all objects in both the foreground & background" when this effect of focal length can so easily be observed and truth be told by this method. In short to answer the OP of " A Fast Fifty Is Really A Fast 75mm", Answer: Yes as far as crop & what fits in the frame; No as far as perspective as a 50mm lens still
projecting the same subject perspective onto the material reacting to the light and turning it into an image; when using digital, you just see less of that projected image because of the smaller sensor when compared to 35mm film... which is where the ##mm nomenclature comes from.