i used the same lenses on my film bodies and on my digital body. at
comparable final magnifications as prints, some lenses continued to perform
at a certain level of sharpness. other ones didn't, dropping a level. no
measurements needed. i am used to seeing certain things being resolved when
i am editing my scans and with my best lenses, i am getting reasonably
comparable results when i am looking at my double-resolution (25MP) images,
after appropriate sharpening. with some lenses that i thought were quite
usable on film, the results are unusable at double resolution and i have to
fall back to actual resolution. the only one i have left now is the 24-90.
for the FA* 24/2, chromatic aberration remained high even then and the lens
hasn't been used much. when i get a chance, i will be trying it again with
the CA correction on Camera Raw 3.1 to see if i can dial in a fixed setting
that corrects it enough so that i can use the lens again because it is a
sharp lens. all of the lenses i ended up disliking came out well before the
*istD. as i said earlier, the 24-90 and 24/2 were the biggest
disappointments both because of their reputations and how well they did on
film, while the FA 50/2.8 macro did exceptionally well on the *istD. as for
across the field sharpness, i made the evaluations while i was still using
my film bodies and got rid of most of the ones i didn't like before i bought
my *istD. the 80-320 did OK on the *istD, but i have better lenses covering
mostly the same range now. i hung onto it only because it took me a while to
acquire the replacement lenses covering the focal length range. i also hung
onto the Sigma 15-30 for a while because even though it was a terrible
performer, it was the only lens that wide that i could easily get my hands
on.
Herb....
----- Original Message -----
From: "J. C. O'Connell" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Sunday, September 18, 2005 9:45 PM
Subject: RE: Pentax K 2.5/200mm
what your saying is not clear ( no pun intended )
to me. The reason I say this is because it's a known
fact that the digital sensors are intolerant of
certain optical designs that film can tolerate
with no abberation. There is also the issue of
the fact that digital and or digital APS
lenses are optimized for maximum image quality
on the sensor, not highest possible image
quality on film and or across the full 24x36 frame.
Since film is far higher resolving power than
current 6Mp APS sensors did you shoot on fine film
and digital with same lenses and compare the
APS cropped film image to the digital image?
Or did you just compare the typical results
of one lens on digital vs another lens of same
focal length on digital?
