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Thread: Long Exposure time Queries

  1. #1
    sadekkhalifa
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    Long Exposure time Queries

    Why P45+ have a 60min. Exposure time & Other Back have 1min or less. I didn't know what is the difference from Technical wise.

  2. #2
    perjorgen
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    Re: Long Exposure time Queries

    Its all about noise...
    Here are some of the reasons:
    - Generally the Kodak sensors have better noise behavior than the DALSA sensor at long exposures
    - The phase + series can group 4 pixels into one reducing noise
    - Phase can capture a black frame giving alot of information on the noise so it can be remove from the main exposure

    I am a Hasselblad user so I am not sure about the details of Phase backs but there are always different types and sources of noise and different ways to handle them and Phase have put a lot of effort into reducing the noise relevant for long exposures on the P45+ (mainly static noise)

  3. #3
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    Re: Long Exposure time Queries

    The H4D 40 can do a noiseless 4 min 16 secs exposure and doesn't require the black frame between shots. With the exception of start trails that time works for me.
    Cheers,
    Jeff
    www.jeff-grant.com

  4. #4
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    Re: Long Exposure time Queries

    It's Phase One's Xpose+ technology that makes up to one hour exposures possible according to http://www.phaseone.com/en/Digital-B...hnologies.aspx

    The same Kodak sensors used by other brand digibacks can't achieve same long exposure results.

  5. #5
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    Re: Long Exposure time Queries

    Quote Originally Posted by sadekkhalifa View Post
    Why P45+ have a 60min. Exposure time & Other Back have 1min or less. I didn't know what is the difference from Technical wise.
    I have both P45+ and P65+ backs.
    There is a lot of fuss in forums about the long exposure issue. In my view, it is only an issue for VERY specific types of photography such as shooting star trails and shooting moving water to make it look smooth. Yes, the P65+ is limited to 1 min exposures, or sometimes less here in the Middle East in summer. As the sensor heats up, it produces "noise" in the shadows. If you haven't seen this before, it looks kinda like film grain but rougher. Software can smooth it, but often at the cost of detail.
    In practice, it is mostly a non-issue as digital lenses tend to be optimised around f8 or so, hence the long exposures necessary when shooting at f16 or f22 rarely happen. I shoot most of my work either in the last glimmer of sunset or after dark (I am a pro architectural shooter) and have only had issues with noise once. Also the latest version of Capture One Pro has much improved noise suppression controls.
    Cheers,
    Siebel
    "In the end, it's all about the pictures"
    www.bryansiebel.com

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