Tom wrote:
> Resolving power is not spread over the image (lenses are
> essentially holographic devices). The medium format lens
> simply has a wider field of view.
I don't get this. I'm no optical engineer but unconceivable to me how you can double
cover area without doubling optical defects as well if you use a constant area as
reference (in this case 24X36). By mounting a medium format lens on a 35mm camera is
basically like adding a perfect teleconverter to a 35mm system lens. Still, you get
reduction of optical quality because you're magnifying optical defects as well.
Say you are projecting a perfect slide with no grain etc with a certain projector
lens at a certain distance to the screen. Say you choose an area within the projected
image measuring 24X36 as reference. Then you move the screen farther away from the
projector (and refocus) so that the image covers a larger area. You still keep the
24X36 area as reference. Wouldnt the area within the 24X36 frame now show lower
resolution because you have magnified all the blemishes in the lens? This is basically
what you're doing when using a medium format lens on a 35mm camera. Also, large format
lenses show lower resolution than 35mm lenses. - the Minox lens has higher resolving
power than 35mm system lenses.
Anyway, my test results of the FA645 45/2.8 and FA645 75/2.8 clearly show that they
are pretty bad when mounted on a 35mm camera. This is of course more compensated for
when using them on the 645 camera because the larger area of medium format more than
compensate for this. Jostein �ksne tested the A645 120/4 Macro, one of the best MF
lenses made, and found that it couldn't compare at all with the M 135/3.5 (I believe
it was this lens) when mounted on a 35mm slr.
[My FA645 120/4 gives comparable results with the A* 135/1.8 when used on a 35mm
camera, but then the FA645 120/4 Macro is an astounding lens}
P�l
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