If you are talking lppm on the film, that's generally true. If you
are talking lppm on a printed image, it ain't necessarily so. In
simplest terms, a 50mm lens with 50 lppm resolution on 35mm film
will deliver the same sharpness on any given size print as a 125mm
lens with 20 lppm resolution on 6x9cm film. (Only talking taking
lenses here, not grain, tonal range, enlarging lens, film base,
yada, yada, yada) The MF image on film is 2.5 times larger, so it
needs 2.5x less magnification to print size. When the question goes
beyond the exact plane of focus, the answers get even more
interesting.
Moose
Winsor Crosby wrote:
It is well known that 35mm lenses are sharper than medium format
and large format lenses.
That is true but the original poster, I believe, just made a
statement regarding sharpness and lens size that I was responding to.
Later I was turning over the idea of a terrific medium format digital
cam about the size of an OM 1 with the increases in pixel count
coming down the pike. However it may not work after all because
medium format and large format do depend on a large film for
increased resolution. Unless there are striking breakthroughs in lens
design. Current lenses will probably need medium format sized CCDs
besides pixel counts.
I also wonder how much sharper a lens designed for a tiny CCD can be
compared to a lens for a 35mm sized frame. That is, if a really good
lens can resolve 80-90 lines per mm and one CCD is 36 mm across and
the other one with an equal number of pixels is 20mm across, which
one will put the most lines in the final print.
There is another big change coming down the pike too. People who were
not pros popped for good cameras because many of them projected
slides. It takes a bit of resolution in that 24 x 36 mm frame to
fill a 50x50 or 60x60 inch screen. All that quality was not needed
for 4 x 6 prints. Since the preferred picture display is quickly
becoming a computer screen there is one less reason for a good high
res camera. That may explain why digital is being embraced so quickly
by people even before it is able to duplicate performance of a good
camera and good film. News pros don't need film, amateurs don't need
film as much, consumers only need it for the sake of simplicity using
the existing film processing infra structure. About the only people
still need 35 film are those that make large prints for exhibit and
those who take pride in the capability of their tools even though
they seldom push them to their limits. Really capable cameras are
going to get even more expensive, I think, than the digital wonders
coming out now. How many of you using digital equipment have it set
on the highest resolution and best quality TIFF now? Hmmm.
--
Winsor Crosby
Long Beach, California, USA
mailto:wincros@xxxxxxxxxxxxx
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