I saw the thread by
Zplus and it spurred me to get this posted.
About a month ago I spent an afternoon/evening making a comparison for myself out of curiosity, and also b/c i thought others might be interested as well. I will post small-size pictures here, with links to full-size jpegs (saved @11 in PS).
Conslusions
I am disappointed/surprised.
BASED ON MY RESULTS IN THIS SPECIFIC TEST WITH THESE LENSES, MY SCANNER, MY LAB, ETC. in terms of resolution 35mm sucks, k10d and 645 are very close - at 10mp size k10d looks sharper, but 645 shows a hint of more beyond, while k10d looks digital - you see all the detail but that's all there is. the 645 at full 3200dpi scan has more detail depth than k10d, but is not as crisp. Beforehand I was confident the 645 would be much better than the APS-C.
Certainly, this is alot of magnification when the files are viewed @100% on screen, but the digital handles it much better than the 35mm.
k10d is very clean! 35mm slide film is very clean! 645slide film would be outstanding, while print film is rather grainy.
colors - not gonna go there in this test.
contrast range - k10d wins. i did not try at all to get more out of the film - and i could, but with RAW the k10d makes it child's play to get so much detail from dark to light.
pleasure of using - 645 wins hands down for the great view through the viewfinder and just as easy as 35mm slr. digital wins for quick satisfaction.
best lenses: choose your own
on bronica i can see the 75 is sharper than the 150 by a little.
Please scroll down past these screeenshots for all of the info and the real pictures k10d w/ sigma 28mm @100% vs. ETRSi w/ 75mm lens @ 50% k10d w/ sigma 28mm @200% vs. ETRSi w/ 75mm lens @ 100% k10d w/ p-fa 35mm @ 100% vs k1000 w/ p-k 55mm @100% Test Details
Cameras:
Pentax k10d
Pentax k1000
Bronica ETRSi
Lenses:
Pentax DA12-24 F4 ED AL (IF) @18mm & 24mm
Sigma Mini-Wide II 28mm f2.8
Pentax FA-35mm f2.0 AL
Pentax K-55mm f1.8
Pentax SMC Takumar 135mm f2.5 (6/6 version)
Bronica Zenzanon PE 75mm f2.8
Bronica Zenzanon PE 150mm f3.5
Image Capture:
Pentax .PEF --> Adobe ACR 5.x (latest) with no sharpening/NR --> jpeg & 11 in PS
35mm Fuji Astia ISO100 --> Epson v700 & Silverfast se 8bit 3200dpi with no sharpening/NR --> jpeg & 11 in PS
645 Fuji NPL 160 (expired tungsten film, always refrigerated) --> same as above (resized to 2592px image height by PS)
Of course, for any real usage these would all need sharpening, especially the scans (flatbed scans always need a lot of sharpening.)
Technique:
Light via 1 Speedlight through umbrella at camera left ~ 45deg up/left. power adjusted to attempt to get even exposure as aperture was changed.
Tripod, cable release, MLU (except k1000), Self-timer (k10d only).
Test at every full-stop from f11 and open, + max. ap. if not a whole stop.
Focusing: microprism collar with k1000, split-image screen with ETRSi, focus bracketing with k10d (about 30 frames through 2ft+ range).
I tried to match image framing, but I realize I did it wrong - I matched with the front of the table, which is ~1ft in front of the subject, oops. This only matters for comparisons btwn focal lengths, btwn formats it should not matter imo.
Images
for comparison I have:
APS-C---35mm------645
18---------28----------x
24---------35----------x
28----------x----------75
35---------55---------75
55----------x---------150
x----------135----------x
135---------x-----------x
*multiply 645 lenses by .6, APS-C by 1.5 for equiv. 35mm fov
Shutter speed was at x-sync for Pentax cameras, 1/500 for ETRSi (but the light is all flash anyway so shutter speed is really 1/1000-1/10000?). EXIF should be intact for the digital, and I have placed a note identifying what the shot is in each picture anyway (though a couple times i forgot to change it - I know 100% the captions i put here are correct).
Pictures Below: