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Thread: Kodak DCS Pro Back 645M

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    Kodak DCS Pro Back 645M

    Hi!
    I am new here, and registered to join a community of MF photographers. I use a Bessa III and Mamiya 645 1000s for a lot of my work - mostly black-white and non-professional, but some more or less "professional" (e.g., all images in the Voigtländer were taken by me with the Bessa).

    I love film, and have a good setup with a Nikon Coolscan 8000 and access to a Hasselblad X1 if I need something for a magazine.

    What I am increasingly considering is a "cheap" MF back, for more casual shooting and when I want color. I came across a Kodak DCS Pro Back 645M. A dinosaur of sorts, I know, but I was wondering:

    - how hard is accurate focus with the Mamiya 645 AFD and a manual lens like the Sekor 110mm f/2.8? The 1000s has a nice split-screen, nailing focus is not a problem. But that is WLF and film....digital forgives less.
    - the sensor itself: Lets say I stick to ISO 100 and 200ish...how well does the IQ fare in comparison to, say, a Leica M8 (my digital reference)? Not so much in resolution, more in clarity and "robustness" of the files (DR, color depth, bw conversions, etc).
    - the Kodak back and modern software - I use Lightroom CC...how is that going to work? I use Xrite with calibrated screen, but does LR read the files well at all?
    - Finally...I can stretch my budget a bit later in the year. Any recommendations for more modern alternatives? Phase One P25?

    For critical work I have the full film thing, so it does not need to "comped" with that.

    I does not have to be a Mamiya, but I like the 645 for film and the lenses (80mm f/1.9 and 110mm f/2.8) and a Contax 645 or Hasselblad would increase the investment again.
    Also: I have no interest in digital FF. APS-C on my Leica X1 is the sweet-spot for size-performance. Any expenses in digital will be in MF.

    Thanks for any advice,
    Peter

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    Re: Kodak DCS Pro Back 645M

    I think an accurate focus is not a problem - but this depends on your subject. If you will have moving thing it's hard with every MF; with everything else it should not be a problem.
    I had a 110mm MF in the past - and still using the 80/1.9. Not really a problem with that (but not moving subjects on my side). Some guys are still crying til today with a DF+ - but I think the cameras are not so bad as their reputation.

    About IQ I can't say really much. But from my experiences with Kodak DCS-camera it should have nearly the same level / especially the color / as the Leica M8. That's one of the positive things, that Kodak-sensors have (nearly) the same look.

    But what you speak about "more modern" is a good thought. I nearly had bought a Kodak DCS-back some time ago - but I'm happy, that I didn't. For example the Kodak-back has no buttons for switch on/off (switch on with the camera). And I had read about some trouble with this; but not sure, if this is really a problem or only with some backs.
    But the same "no Powerbutton" has the Mamiya ZD. So it's the same way.

    So - if you are going to spend a little bit more money you should think about your need. Perhaps for the next years.

    If you love the square-format: think about a P20 (randomly I'm selling mine... )
    You can find a little bit about the IQ here: http://forum.luminous-landscape.com/...?topic=98575.0

    If square-format is not your favorite: then think about an other backs. If it's in your price-range a P25 / P30.
    P25 (48x36) if you shoot more landscape or want perhaps to use a technical camera; P30 (44x33) if you want to shoot more people (a little bit higher Iso possible; but you got microlenses - that's a no-go for technical cameras).
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    P.S.: If your wife knows everything... it's mostly not good for your gear.
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    Re: Kodak DCS Pro Back 645M

    Don't buy a Kodak DCS, they are no longer repairable and will become an expensive paperweight the second it stops working, it's also got way too many quirks to be really enjoyable to use. You are much better off with one of the early Phase One backs, I have a P25 myself and it's lovely.
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    Re: Kodak DCS Pro Back 645M

    I used the DCS645M for several years and enjoyed it - but that was over 14 years ago!!. It's an old back and it wasn't exactly reliable with the 645 bodies even then (they would randomly lock up), plus spares are basically unavailable. I had one fail and it was cheaper to replace it vs repair and that's when there were still repair options and parts. That's pretty much over now - anything happens to it and it's dead.

    Also, you're going to have a hard time finding batteries.
    Remember: adventure before dementia!

    As Oscar Wilde said, "my tastes are simple, I only like the best"
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    Subscriber & Workshop Member GrahamWelland's Avatar
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    Re: Kodak DCS Pro Back 645M

    Btw, if you're interested in the square format MFDB at an affordable price and with better resilience and support I'd seriously consider Christian's P20. Heck, if it was in Rollei mount I'd buy it myself.

    Hint: if anyone has a decently priced working DB20p for the Rollei 6008i2 I'll buy it. I don't care about cosmetics although it must be 100% functional.
    Remember: adventure before dementia!

    As Oscar Wilde said, "my tastes are simple, I only like the best"
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    Re: Kodak DCS Pro Back 645M

    Hi all,

    thanks for the helpful replies, they are greatly appreciated!
    I am thinking about Christian's P20 - great offer. I need to source a reasonably-priced body first (the Kodak offer would include a Mamiya ADF).

    Best,
    Peter

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    Senior Member kdphotography's Avatar
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    Re: Kodak DCS Pro Back 645M

    The Kodak 645M was an awesome MFDB. Great images out of the box and easy to use. Achilles heel now is the lack of support, parts, etc. It's a dead end if it breaks down.
    Kodak special looks software was an idea eons ahead of the competition---and easy.

    Batteries are an issue now. There was an adapter cord made by Quantum that allowed you to use their Turbo battery to power the Kodak 645M/C/H, and assume Kodak Proback too.

    ken

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    Re: Kodak DCS Pro Back 645M

    Hi!
    So, the seller does actually not a have the charger anymore. That is not good, but would lower the price a lot. Any after-market solutions, besides the Quantum? Can one charge the batteries when attached (w/o charging unit)?

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    Senior Member kdphotography's Avatar
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    Re: Kodak DCS Pro Back 645M

    I don't recall being able to charge the battery using the back. I had most everything you could think of when I had my 645M, which is why I know about the Quantum cable solution to a Quantum battery. That cord may be a challenge to find (dunno)---I sold mine long ago. You could check with www.qtm.com

    I would be hesitant to purchase a 645M---but if you know what you're getting into, and the risk of repair.....

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    Re: Kodak DCS Pro Back 645M

    Like Ken I powered mine externally using a DigitalCameraBattery (DCB) battery most of the time. Same set up as the quantum. I probably still have that stuff around here somewhere but it was primarily due to the batteries losing charge over time and the need for lots of them.

    Ah yes, the Kodak looks software and the really nice converter app. I miss them.
    Remember: adventure before dementia!

    As Oscar Wilde said, "my tastes are simple, I only like the best"
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    Re: Kodak DCS Pro Back 645M

    Hi!
    Ended up buying the 645M back with a Mamiya AFD. I can charge the batteries, too, using a Canon video camera 8V charger and wires (the batteries have four contacts, but only two deliver power, its as simple as for any other battery).
    I also have a Quantum Turbo C battery coming, and found a YDC5 Quantum cable. Robert White in the UK has one left in stock.
    Thanks for all the input!
    Peter

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    Re: Kodak DCS Pro Back 645M

    Quote Originally Posted by Peter_S View Post
    Hi!
    Ended up buying the 645M back with a Mamiya AFD. I can charge the batteries, too, using a Canon video camera 8V charger and wires (the batteries have four contacts, but only two deliver power, its as simple as for any other battery).
    I also have a Quantum Turbo C battery coming, and found a YDC5 Quantum cable. Robert White in the UK has one left in stock.
    Great choice. Though ProBacks and Kodak SLRs may be out of support and repair, you will find that there is a community of people actively using, maintaining and eveb improving them. I wrote free software that allows you to perform a sensor remap for Kodak ProBacks and SLRs as well as a bunch of other free tools (not yet open source but will be eventually when I tidy them up). For example, a tool to extract the build-in profiles from raw DCR files - those are unique for the sensor calibrated by Kodak (in both ICC and DCP shape).

    There is a thread on DPReview with details and links to the remap software. Also there are more active threads about Kodak ProBacks on russian forum these contain a lot more links and explorations (including hardware ranging from improving the heat dissipation within proback to projects to repaint it white) so use google translator if needed:

    1) the thread with all the software mods/utils and links in the first post (in russian). This includes lost of sofware investigations as well as anything Kodak ProBack and SLR related - IR filter replacement sources for example.

    2) the hardware thread trying to repair one of the ProBacks - this includes (closer towards the end) some mods posts - heat disssipation, repainting (in russian)

    3) thread about replacing the cells in ProBack rechargeable battery - makes single battery last for 600-700 shots on single charge (in russian)

    4) post in a thread about calibration with ProBack spectral sensitivity readings and data - these in theory should be enough to build any profile for any illuminant (this is ongoing work and also in russian).

    You and other ProBack users may find some of this useful.
    Last edited by AlexeyDanilchenko; 25th August 2015 at 06:37.
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    Re: Kodak DCS Pro Back 645M

    Thank you, Alexey, for the links and the throughout work you put into keeping the backs up and running!

    I will spend next winter in North Norway, working as guide. I normally only work there in the spring.
    Of course I would like to capture the northern lights. With the Pro Back 645 on my Mamiya AFD I did not have much success with long exposures so far (the heat and hot pixels), and I am not sure if the system is a good choice. Then again, I do want to invest into another digital system; plus, the Mamiya lenses are cheap and I like the large sensor.

    Any tips/tricks to make the Pro Back perform in the Norwegian winter? Cold should not be an issue, I have an external battery pack.

    I will look into Alexey's remapping software, which may solve some issues. But how to best mitigate the hot pixels?
    Any tips are welcomed.

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    Senior Member ondebanks's Avatar
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    Re: Kodak DCS Pro Back 645M

    Peter,

    Alexey and his colleagues in Russia are doing excellent work in understanding and improving the venerable old Proback DCS645.

    Do get his firmware! For long exposure shooting, the best feature I found in the special engineering sections of the menu is the ability to turn off black (bias) subtraction. Not the same as turning off the long exposure processing (dark frame recording and subtraction), mind; that was always possible in the Proback's menu (Phase One, take note!!). This goes one step further and doesn't even subtract the electronic bias offset at each pixel before writing the RAW frame. Which means that pixel intensities are reproducible and scale linearly regardless of the temperature of the back. Whereas previously, the bias level subtracted would rise and rise as the back got hotter, affected by dark current in the border pixels reserved for determining the "black" level; it ended up oversubtracting into the shadow detail, and pretty much ruined my attempts at dark frame subtraction at the post-processing stage. Not any more.

    I am currently working on a software approach to automatically match frames, taken without bias or dark subtraction, to the corresponding best-fit dark frames, also taken without bias subtraction. Then one can do the bias & dark subtraction post-camera, and with greater optimization. Not needing to do it in-camera saves more than half the time: instead of a 30 sec exposure + 30 sec dark frame + something like 12 seconds processing, it is now just the 30 sec exposure. The time saved can be used to either keep shooting, or to leave the back cool down considerably again before the next shot.

    But how to best mitigate the hot pixels? Any tips are welcomed.
    For the first few years I had the DCS645M, I used the original Kodak Photodesk software for RAW conversion. I switched to RAWTherapee this year as it is just so much more powerful and works a treat with the Proback files. For one thing, it can filter both hot and dead (more likely, dark-oversubtracted) pixels in the RAW with great precision. It's even better if you use its ability to subtract a separate dark RAW frame first, then follow up with residual single-pixel filtering. I also love how there is a setting to not de-Bayer images taken with the DCS645's IR-block filter popped off and an IR-pass filter over the lens (a regime where the Kodak sensor becomes essentially equally sensitive at all pixels, removing the need for spatial interpolation). Great software, and it's free!

    Ray
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    Re: Kodak DCS Pro Back 645M

    Hi Ray,

    this is all brilliant! I am impressed.
    I am digging through all the pages, incl. the Russian ones (I speak a bit). I am having troubles finding the Firmware for the Proback - only 14n and SLRs.
    Would you have a link?

    I have until November, and will see how much the firmware modifications and remapping improve the performance.

    Many thanks! Peter

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    Re: Kodak DCS Pro Back 645M

    Quote Originally Posted by Peter_S View Post
    this is all brilliant! I am impressed.
    I am digging through all the pages, incl. the Russian ones (I speak a bit). I am having troubles finding the Firmware for the Proback - only 14n and SLRs.
    Would you have a link?
    It is actually stated on the very first page with firmwares - the service mode firmwares are bundled with DCSRemap (SLR/n have separate firmwares that remove the lossy compression). So download the software and unpack it - there will be a directory with firmwares in it (on Mac ots hidden in app folder so you need to use Show Contents in Finder). Upload the one for your camera by standard means (i.e. apply it from CF card twice). After that the new submenu should appear at the end of normal menu Imager, Properties (all of them not just a few) and others.

    You can still run the camera with this firmware (I do) but bear in mind that it has service mode permanently on and in this mode it does not report some of the errors and conditions (like date time being reset, some errors in writing data from sensor when it gets hot etc).
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    Re: Kodak DCS Pro Back 645M

    Quote Originally Posted by ondebanks View Post
    For the first few years I had the DCS645M, I used the original Kodak Photodesk software for RAW conversion. I switched to RAWTherapee this year as it is just so much more powerful and works a treat with the Proback files. For one thing, it can filter both hot and dead (more likely, dark-oversubtracted) pixels in the RAW with great precision.
    Ray,

    You don't need RT for that - just remap them once using DCSRemap and repeat every now and then when new ones appear (that is not very frequent). I would basically recommend the following to do it effectively:
    1) take a few dark shots at 1/4 or 1/2 sec
    2) load raw in DCSRemap and select several of those raw files at the same time (up to 7 of them) - the DCSRemap will load them and take a median at each pixel which will ensure only stable defects will persist across the shots
    3) tweak the exposure in DCSRemap to make the dark pixels more visible and manually remap the columns (if there are any stripes)
    4) save the remap
    5) tweak and run adapive pixels remap picking various thresholds and block sizes - this will basically for selected block size find the median for each colour channel and mark the pixels (for remap) that are differing from it above the selected threshold value
    6) if anything is not correct at (5), select Reset and repeat (5) again

    I find it works quite well - better that Kodak original remap. The only difficult part is to pick the right thresholds, too small and a lot of pixels will be remapped, too high and it will be ineffective so it needs experimenting (hence the step 6). Also if there are too many pixels remapped (>2000-4000) some Probacks do struggle a bit - to help estimate it the info panel will show the amount of pixels that falls out of thresholds when you change the thresholds (Auto.Def column on Remap tab).
    Last edited by AlexeyDanilchenko; 4th September 2015 at 01:26.
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    Re: Kodak DCS Pro Back 645M

    I wanted to add a note of caution regarding of usage of my DCS Remap application. It is a very technical thing to do the remap, so please before you rush to do anything, read the help pages that come with it several times. I cannot stress how important it is to understand what remap for Kodak ProBack actually does and hence understanding what DCS Remap is doing (and all its doing is editing the sensor file that contains amongst other things information about sensor defects). This will avoid messing up the file.

    Also using a good CF card to save and read amended sensor file (TEST.IF) is paramount - quite a few people loaded the file back into ProBack from rubbish card and discovered that it completely messes up the ProBack image capture.
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