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Thread: a scanning back question

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    a scanning back question

    greets again all,
    Kindly allow me to pose this: can one use a PowerPhase FX for portraits?
    Is this possible? Allow me to qualify by saying that:

    1. I would be shooting in controlled conditions with continuous light (daylight or hotlights) using silks and an improvised light tent.
    2. I would welcome any lines, streaks, color shifts or any abnormalities
    3. I would be using a Deardorff w/ a 4x5 reducing back.
    Previously I had been using Pola Type 55 and love all sorts of accidents.
    I would also have access to a generator, hot lights, etc...
    Needless to say, its a big production, and the slower the process the better.
    4. Why this model? I can only deal with Firewire.

    Has anyone tried this? What are the mechanics anyway of shooting with a scanning back?
    what sort of exposure times do you normally get with low ASA and bright sunshine from a scanning back?
    what happens if you fire a strobe during a scanning exposure?

    my subjects would of course have to figure out how to hold their breath for as long as necessary (mwa ha ha)...or I may have to rig some Victorian-era thingamajigs...
    thanks in advance...

    PS am now in the hunt, and hope to be a P45 or P45+ owner in a couple weeks..so getting this might be better use of $$ than getting a 4x5 adapter for the P45, and lots more fun.

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    Re: a scanning back question

    Dave Gallagher (owner) and I (Head of Technical Services) have a lot of experience with the Powerphase FX+.

    "2. I would welcome any lines, streaks, color shifts or any abnormalities" <-- that is the key to your question. As long as you specifically looking for it you may well fall in love with the very strange way that scanning artifacts. For instance, imagine that during the exposure the model changes slowly (and with several attempts to get the timing and technique right) from a frown to a smile. The left side of her face could be in a smile while the right side is in a frown; it will be far from flawless, but done correctly it would create a pretty unique effect.

    You do need a lot of light, but sunlight supplemented by hot-lights as needed will be more than adequate. Exposure time goes down to 1/125th sec per line and the length of the total exposure is a combination of the exposure-time-per-line and the number of lines scanned (the longer dimension). I would have to set one up to get exact numbers but at 132 megapixels with sufficient light you're looking at maybe 2.5 minutes, and at 33 megapixels about half that. I'll see if I can get some more exact numbers for you.

    Mechanics of shooting with a scanning back are really really close to shooting with a film holder.
    - Focus/compose on the ground glass
    - take an initial meter reading with a light meter
    - insert and lock the scan back (slides in like a film holder)
    - take a "polaroid"; in this case a very low resolution preview (takes 10-30 seconds)
    - if desired take a full-resolution of a small part of the frame to confirm focus
    - take the full res scan (generates a 16-bit RGB TIFF)

    In cases where you have control over your light and it is possible you would use the slowest ISO of 200. However, as needed you can boost the ISO to 400 at full resolution or 800/1600 at reduced resolution (still a huge file).

    If you haven't seen it a datasheet can be found at http://www.phaseone.com/upload/fx+us.pdf

    Doug Peterson (e-mail Me)

    My company really shines when it comes to odd-ball projects. I'm completing a consultation/research for a client on 5X macro work with a P65+ and in the past have done infrared modification tests, digital multiple exposures (true multiple exposures, not digital composites), etc. We would love to help you work this out. I'll have to check with the Atlanta office but last month we had three scanning back with warranty left (very rare for an FX+) and I believe we still have one. We can also help with that P45 :-).


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    Re: a scanning back question

    As a follow up - the artifacts when shooting at 1/125th is only along the horizontal axis. In other words slight subject movement frame-up and frame-down is frozen by the 1/125th effective shutter speed. Low frequency movement left and right changes the width/compression/expansion of the subject and leaves strange artifacts. A lot of cool effects can be created by taking advantage of this. If the subject is still while the system scans the left third of their face, but then slowly slides to the right during the rest of the exposure the result would be a face which was recognizable and sharp but looked smashed in. You can accomplish simple versions of these effects in photoshop, but some effects would be impossible (or highly difficult) to create otherwise which means you could produce some very unusual, maybe even unique, imagery.

    Of course you do need a LOT of light if you don't have the light of the sun. f/8 on a view camera 4x5 frame is going to be shallow for DOF and accomplishing f/8 ISO200 1/125th light in-studio is going to make your model very sweaty. That will be your biggest obstacle. Of course you can go to ISO400, down to f/5.6, or down to 1/60th or 1/30th but each would come with some compromise (slightly more noise, less DOF, and longer scan times respectively). It would be a good idea to walk around a bit with a light meter to see in what lighting situations you can get to f/8 ISO200 1/125th light.

    In case I haven't been clear I think it's a crazy nutso idea, but that's why I love it, and I have a feeling you feel the same way. Highly impractical, but possible with effort, and very interesting. That's the type of photography I love!

    Doug Peterson (e-mail Me)
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    Re: a scanning back question

    Also, if you fired a flash during the exposure you would only effect a single vertical line of the image. You could use a stroboscopic light which fires faster than 125hz with some interesting results, or could vary the intensity of the continuous lights during the exposure which would lead to soft-edged bands of exposure similar to uneven development when tray processing an 8x10 negative.

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    Re: a scanning back question

    Doug - dude you just blew my mind.
    a certain caveat - just found out a PowerPhase isn't exactly the price of an adapter..
    and a shame one can't freeze action, or just a clear image, with a strobe...
    also I was thinking more along the lines of 5 second exposures..

    but then this is more like light painting now, isn't it?
    dang! - ohmigod, the possibilities..
    no sleep for the wicked tonite, thanks to you!

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    Re: a scanning back question

    Quote Originally Posted by ocarlo View Post
    Doug - dude you just blew my mind.
    a certain caveat - just found out a PowerPhase isn't exactly the price of an adapter..
    and a shame one can't freeze action, or just a clear image, with a strobe...
    also I was thinking more along the lines of 5 second exposures..

    but then this is more like light painting now, isn't it?
    dang! - ohmigod, the possibilities..
    no sleep for the wicked tonite, thanks to you!
    You're certainly off in largely unexplored territories.

    Again, the image will be detail-sharp (1/125 will be enough to freeze normal shake of the model) but have a very strange of anything moving at the time the scan hits that movement.

    Definitely no way to get anywhere close to 5 seconds. However at 8 megapixels you'd be at 40 seconds or so.

    $4,900 is what we listed the scan back at with about 6 months of warranty remaining.

    Doug

    Doug Peterson (e-mail Me)
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    Re: a scanning back question

    Don't forget guys that the sensor is scanning three individual lines of R,G,and B at the same time; a single flash fire would give an RGB stripe across the image...

    Multiple out of sync strobes would be interesting, to say the least!

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    Re: a scanning back question

    Quote Originally Posted by shakeshuck View Post
    Don't forget guys that the sensor is scanning three individual lines of R,G,and B at the same time; a single flash fire would give an RGB stripe across the image...

    Multiple out of sync strobes would be interesting, to say the least!
    Indeed!!! Good catch.

    Doug

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    Re: a scanning back question

    Quote Originally Posted by shakeshuck View Post
    Multiple out of sync strobes would be interesting, to say the least!
    hmmm...cool...any other ways to subvert this puppy?
    I'm gathering that in psychological terms, this would indeed be like shooting with a desktop scanner for a camera, only much longer scan times?

    Do you see the image building up on the laptop screen?
    are there indicators for how much time is left?
    in horizontal orientation, does it scan sideways or top to bottom?
    I guess I' m trying to get at a system for predicting where and when
    in the scan process to do certain actions...

    i've read the pdf but can't get clear as to how to set exposure and shutter speed...oh wait, duh? i would have to be on Bulb...but then how do you equate scan time vs. length of shutter being open??
    and why is the most fine-grained ASA at 200 instead of 50?

    am truly a newbie boy in the woodsies here...sory.

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    Re: a scanning back question

    I'll answer what I think I can remember, Doug will have to fill in the gaps or correct me as necessary!

    Quote Originally Posted by ocarlo View Post
    this would indeed be like shooting with a desktop scanner for a camera, only much longer scan times?
    Absolutely. But you can select as much or as little of the sensor as you want for the final shot. If you choose 1/125 second line time, and your selection covers 125 lines, it will take 1 second.

    in horizontal orientation, does it scan sideways or top to bottom?
    The sensor sits across the width of the back, and travels along its length; so sideways for horizontal orientation.
    But if you can make do with 10,000 pixels for length , you can select an area across the sensor and it will (effectively) scan from side to side for portrait orientation, too.

    I guess I' m trying to get at a system for predicting where and when in the scan process to do certain actions...
    I like where your thought processes are going...

    i've read the pdf but can't get clear as to how to set exposure and shutter speed...oh wait, duh? i would have to be on Bulb...but then how do you equate scan time vs. length of shutter being open??
    Yes, Bulb. Hopefully my brief explanation above answers the rest of this question?

    Graham.
    Last edited by shakeshuck; 28th April 2009 at 11:40. Reason: Explaining my explanation?

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    Re: a scanning back question

    [QUOTE=shakeshuck;95139]Absolutely. But you can select as much or as little of the sensor as you want for the final shot. If you choose 1/125 second line time, and your selection covers 125 lines, it will take 1 second.

    cheers shakeshuck for all the really helpful stuff.

    i'm really turned around now but slowly waking up to the metaphor...
    i have to remind myself the control is in the software - so just like a flatbed scan, you can select only certain parts of the scane area...

    hmm...so if one was doing composites over several takes of say, landscapes and people, i could do full frame for the background, and just make selections for figures or objects?

    mindblowing...thanks again...carlo

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    Re: a scanning back question

    Quote Originally Posted by ocarlo View Post
    hmmm...cool...any other ways to subvert this puppy?
    I'm gathering that in psychological terms, this would indeed be like shooting with a desktop scanner for a camera, only much longer scan times?
    A lot of desktop scanners take 10-30 minutes to do their highest resolution scans, but yeah, scanbacks are sort of a hybrid of a film scanner and a one shot digital camera.


    Quote Originally Posted by ocarlo View Post
    Do you see the image building up on the laptop screen?
    are there indicators for how much time is left?
    When doing a preview (aka Polaroid) you see the preview generate in real time (left to right). When shooting the final capture you get a time remaining (very accurate) in seconds.


    Quote Originally Posted by ocarlo View Post
    in horizontal orientation, does it scan sideways or top to bottom?
    You've got TONS of resolution to use here, so you could orient vertically and crop to a rectangle and still have 60-70 megapixels (and a proportionally shorter scan time).


    Quote Originally Posted by ocarlo View Post
    i've read the pdf but can't get clear as to how to set exposure and shutter speed...oh wait, duh? i would have to be on Bulb...but then how do you equate scan time vs. length of shutter being open??
    The lens stays open and requires no cable release; just stop it down to the shooting aperture.

    "Shutter speed" (exposure time per line) is controlled by a slider in the software. ISO is set in the preferences.


    Quote Originally Posted by ocarlo View Post
    why is the most fine-grained ASA at 200 instead of 50?
    The "engine" of a P+ single-shot back and the FX+ scanback are very different. The FX+ sensor lines were actually made by Sony. Very different designs, so this question is kind of a non-starter. ISO200 just happens to be the base ISO of this sensor.

    Doug Peterson (e-mail Me)
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    Re: a scanning back question

    Quote Originally Posted by ocarlo View Post
    i'm really turned around now but slowly waking up to the metaphor...
    i have to remind myself the control is in the software - so just like a flatbed scan, you can select only certain parts of the scane area...

    hmm...so if one was doing composites over several takes of say, landscapes and people, i could do full frame for the background, and just make selections for figures or objects?
    Yup; you've got it. The scan time will always be dependent on the number of lines in the long direction (of the scanner), so in a landscape orientation you could have 1/4th the scan time when scanning a model standing vertically in the frame only taking up a fourth of the width of the frame. Assuming your tripod was sturdy and you were careful not to kick anything your registration would be perfect between composited frames.


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    Re: a scanning back question

    Actually, if your model is fast enough, as soon as the scan of them is done on the early side, they can rush around behind the camera and set up on the opposite side before the scan head gets there and appear twice, perfectly, on a single capture.

    A few really neat images I've seen done with scanning backs are of bodies in motion like dancers moving slowly and wind-mill power generators.

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    "Perfection is not attainable. But if we chase perfection, we can catch excellence."

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    Re: a scanning back question

    Here is an example of the kind of crazy images you can make with a scanner, and probably with a scanning back too:

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    Re: a scanning back question

    Francois, that's fantastic!

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    Re: a scanning back question

    I second that, that's cool!

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    Re: a scanning back question

    Francois - a perfect image to start my day!! merci.

    The more I think about it, the more I want it. There is something very strange going on,
    as in a time warp where turn of the century 8x10 meets 2009 Photokina.
    A wooden Deardorff, with mid-century lenses, tethered to post-9/11 technology.
    All the preparations for one shot - as if one was shooting with 8x10 coated glass neg.
    The aspect of time flowing within - 40seconds to 8 minutes - where anything can happen, and whatever happens, leaves a mark.
    Not one - but anywhere from 2 to 8 Decisive Moments within one frame.
    Not to mention the pixels of a future P200+.

    What i really want to see is how, within those parameters, one is able to get as little funhouse distortion as possible, like a hi-def still image shot with a slow shutter exposure, but with sharp definite rendition of key features, as if shooting with a hotlight/strobe combination.
    A way of working that i guess I just have to go through...

    I have already lined up my locations and models, and hope to be back Stateside to get the rig in a few weeks.
    many thanks for all your help, good people.

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    Re: a scanning back question

    Thanks Doug, shakeshuck and ocarlo!

    Regarding the PowerPhase FX+ scanning back, what kind of dynamic range one can expect? How does it compare with DSLR and MFDB?

    How does the image quality compare with the Betterlight scanning backs?

    Is there any lens cast with wide angle lenses like the Schneider 47XL, which would require another scan of a white target?

    Thanks,
    François

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