Mamiya 645 and Kodak DCS Back vs Sony a900

[Mike Sellers]

Is there any advantage in terms of making big 30x40 enlargements in using the Kodak DCS compared to a Sony a900? Are there ANY advantages in shooting with the Kodak over the a900?
Mike

[MichaelEzra]

4x3 vs 2x3 sensor ratio for 40x30 prints !

[ErikKaffehr]

Yeah,

If 40x30 prints are what you need. There is also a technique called cropping...

My guess is simply that your milage may vary. It's not just the sensor, it's also what you put in front of it (subject, lens), under it (tripod) and behind it (photographer).

By the the way, Ezra gets all the things above right...

Best regards
Erik

4x3 vs 2x3 sensor ratio for 40x30 prints !

[Mike Sellers]

Does the larger MP rating of the Sony have any bearing on the print quality? 25mp on the Sony compared to 16 mp on the Kodak?

[ErikKaffehr]

Hi,

I'd suggest it depends much on the lenses and also on your capability focusing them. I wouldn't expect a large difference. The Sony has an OLP filter and therefore needs more sharpening. The Kodak lacks OLP filter, so it may look sharper but cause a lot of aliasing and Moiré.

I think Michael Reichmann had one of those Kodak backs on his Contax but gave up when the Canon 1Ds arrived. With Phase One P45 he returned to MF.

Best regards
Erik

Does the larger MP rating of the Sony have any bearing on the print quality? 25mp on the Sony compared to 16 mp on the Kodak?

[tho_mas]

4x3 vs 2x3 sensor ratio for 40x30 prints !

Ezra gets all the things above right...

nope. 1:1 vs. 3:2 ratio. The Kodak DCS sensor is a square format (36x36mm I believe).

Does the larger MP rating of the Sony have any bearing on the print quality? 25mp on the Sony compared to 16 mp on the Kodak?

If there is any advantage for either of the cameras it's likely relatively small. But the look is certainly different.
I'd say the uncropped 18MP of a P21 (or Leica M9) will look "better" (whatever) than the A900 in print... but it also depends on the lenses. The P21 will certainly show much cleaner differentiation in dark tonal values.
It also depends on the ISO setting, of course... at ISO400 the A900 is much cleaner... than again, the look of the P21 at ISO400 is nice. A bit noisy, but it's a "nice" noise ... somehow (IMO).
With a cropped sensor on a MF camera you are actually always using the sweet spot of the lenses; of course this adds to the look of the final image.
Bottom line: in the 16-18MP MFD range (and Leica M9) the difference is primarly in the look of the photographs... not so much in the resolution. IMO.

 

[tho_mas]

The Sony has an OLP filter and therefore needs more sharpening.

you seem to think that you can recover the blur of the AA filter with a larger amount of sharpening?! This is simply not true. Not even with deconvolution sharpening.

The Kodak lacks OLP filter, so it may look sharper but cause a lot of aliasing and Moiré.

are you reporting from personal expierence or only from hearsay based on internet reports?
Of course non AA filter sensors can produce aliasing and moiré... but very often it's not a problem at all.

[BobDavid]

In the longrun, you'll have better performance, versatility, and resale value with a Sony a900. Or, if you want to save a bit without compromising image quality, the a850. I've shot with a 36X36 16MP back on a Mamiya AFD platform. It was capable of rendering nice files, however, a Sony full-frame is too. The Carl Zeiss 24-70mm f/2.8 is a gem of a lens and makes the Sony sing.

[ErikKaffehr]

Hi,

What I have written is that a device with OLP filter needs more sharpening. I did not write that all blur created by the OLP filter can be recovered.

On the other hand I have seen a lot of Moiré in samples from both Leica S2 and Pentax 645D. Interestingly enough all the samples I studied carefully:

Leica S2: http://echophoto.dnsalias.net/ekr/images/LC_S2_D3X_Eval/ScaledAndSharpend_MassiveAliasing.jpg

Pentax 645D: http://echophoto.dnsalias.net/ekr/images/Pentax645D/Moire_small.jpg

So it's not hearsay, at least in the sense that I have seen it in "raw" samples I processed myself. Now, aliasing occurs only if the lens outresolves the sensor, or technically speaking has high MTF at Nyquist limit. This will obviously be a larger problem with large pitch sensors than with small pitch sensors. So I would expect the problem to be more serious with a 16 MP sensor than say with a 40 MP sensor of the same size.

Lloyd Chambers has found that color moiré by and large disappears on the Leica S2 at f/11, due to diffraction. On a 16 MP sensor it would need to be stopped down to f/16 or even f/22.

Best regards
Erik Kaffehr

you seem to think that you can recover the blur of the AA filter with a larger amount of sharpening?! This is simply not true. Not even with deconvolution sharpening.
are you reporting from personal expierence or only from hearsay based on internet reports?
Of course non AA filter sensors can produce aliasing and moiré... but very often it's not a problem at all.

[MichaelEzra]

I certainly stay corrected on the sensor ratio:)

However, personally I would not try to make a 30x40 print from either of these cameras.
Such magnification certainly can be made, but if subject matter and shooting conditions allow I would try to significantly increase the resolution at capture.
Limited by the equipment mentioned, I would try to do a stitching similar to schematics in the attachments.
My choice in such case would be the camera which would allow for a proper execution of the sequence of individual frames.

I simply find pixel peeping too tiring. We spend too much time counting these little guys:)
They are given to us in millions, so why bother improving a mere hundred or a thousand, which will always be subject to equipment imperfections, - when we can simply double it, triple it, etc.
Larger sensor "look" is an important factor, but if properly done this technique can also manage it well.

Sony would be a more flexible and versatile system in my opinion. Kodak DSC back would confine execution aspect to a more limited range.
You can also consider having both;)

[Graham Welland]

Something else to consider is the long term viability of the DCS route. I used to shoot with the 645M with an AFD and had just too many interface problems between the back and the camera body. AFD II was better but unfortunately the annoyance of countless battery out of body & back resets got the better of me by then. The other considerations are the difficulty of sourcing batteries and unfortunately the (excellent btw) Kodak raw converter hasn't been updated since 2004 or so. Heaven forbid that anything goes wrong with the DCS back too - the good news is that its probably easier these days to just buy a replacement because any digital problems will basically scrap it now (and i know from experience that even a few years ago they were hellishly expensive to fix anyway).

As regards quality & 4x3 crops, remember that you are only starting with 16mp, albeit relatively robust pixels, so your final results are only going to be 12mp by the time you've finished. I preferred to keep my 645M as square images, although that was also in part because I actually find that aspect ratio works for me composition-wise. Depending on the subject you're going to want more than 12mp for a good 40x30" print IMHO. Also, you're not getting the benefit of 16bit MF images with the Kodak either so that's not a compelling reason for it vs a more state of the art DSLR.

I really don't wish to be such a downer about the Kodak as it served me very very well back in 2001-4 or so. However, unless you already own it, I'd look at a more recent DSLR alternative such as the Sony or one of the competitors. I always hear good things about the Sony's color rendering although I confess that I'm a Nikon / Phase One man myself.

[mikeseb]

I shot with the Contax 645 version of the Kodak DCSPro 645 back, until I sold it nearly two years ago to return to MF film. I would not buy one now; the thing is ten years old and parts and service aren't getting any easier to find.

The back itself produces a nice file, but its mechanical and interface quirks just proved too much. For instance, on a hot summer day, shooting outside, the back frequently overheats and shuts itself down to cool off! It's so noisy as to be useless above 250 or 320, depending on your tolerance for a crappy file.

I just purchased a Pentax 645D and I'm trialing it to see if it will do the job for me. If I don't stay with it, I'll probably look at either the D3x or whatever Nikon supplants it with this spring (as rumored.) The Sony Alpha mentioned here would also be a better choice.

[tbosley]

Does the larger MP rating of the Sony have any bearing on the print quality? 25mp on the Sony compared to 16 mp on the Kodak?

I would read up on the:
" The Megapixel myth"  &  Photosite size, or why “size matters”

Micheal of LL has written some excellent articles over the years that touch on these areas.


BTW- buying into a dead system only matters as long as its not the Contax 645...

[Graham Welland]

I would read up on the:
" The Megapixel myth"  &  Photosite size, or why “size matters”

Micheal of LL has written some excellent articles over the years that touch on these areas.

In general these are very valid points but I fear that in this case you really also need to factor in the advancement of technology and image processing improvement in the years from when the DCS backs were produced and today. If you were comparing something like a Phase One P20+ or 'blad CFV 16mp back with the A900 then certainly the megapixel myth, sensor size, 16bit image capture and improved image processing advantages would be a fairer comparison.

[tbosley]

Are there ANY advantages in shooting with the Kodak over the a900?
Mike

Not wanting to ruffle any feathers - especially during the holiday season

But sure there ARE advantages.  One being if you already have fantastic Mamiya glass.   

You realize no one has enough information on what Mike shoots and where to make any definative judgements, but the latest and greatest does not always make the best choice.