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Thread: CFV-39 Hot Pixels

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    CFV-39 Hot Pixels

    I have been saving my nickels and dimes for quite some time and yesterday took delivery of a beautiful Hasselblad CFV-39 with about 1000 actuations on it. I charged up the battery formatted my 600x CF card and started some testing of the back. I immediately noticed a large number of hot pixels in my images especially images with dark tones. I am hoping someone can help me out with this because I really want to keep it.

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    Senior Member EH21's Avatar
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    Re: CFV-39 Hot Pixels

    Make sure you also view the images on the computer. On some backs what you see on the rear screen is not the final image since some back previews don't contain all the final processing. That said, I did have a hasselblad back that had a few hot pixels and I sent it in to their service and they recalibrated it, and I guess mapped out the pixels. Cost was about $450 but it took 1 month.

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    Re: CFV-39 Hot Pixels

    Quote Originally Posted by EH21 View Post
    Make sure you also view the images on the computer. On some backs what you see on the rear screen is not the final image since some back previews don't contain all the final processing. That said, I did have a hasselblad back that had a few hot pixels and I sent it in to their service and they recalibrated it, and I guess mapped out the pixels. Cost was about $450 but it took 1 month.
    Yes I view them in Phocus and most of the bad pixels do get mapped out but I think the sheer number of bad pixels is a bit excessive. My understanding is that a calibration file is applied in the back immediately after capture that maps out the bad pixels (Well for Phase One anyway). Seems that maybe this back has drifted a bit from the original calibration file and could need to be re-calibrated. It just seems like this many bad pixels is more than I am willing to accept. I am hoping for a simple and less expensive solution, but do not have high hopes.

    Thanks for the reply!

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    Senior Member EH21's Avatar
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    Re: CFV-39 Hot Pixels

    Just curious, how long an exposure are you doing in your tests? At base ISO and short exposures, I'd expect to not see any hot pixels after opening in Phocus, but at higher ISO and long exposures you may seem some. One question is do they always appear in the same spots or random?

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    Member Douglas Fairbank's Avatar
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    Re: CFV-39 Hot Pixels

    To add to what EH21 said, check that the firmware on the back is up to date and if it is not get the update from the Hasselblad website and install it.

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    Re: CFV-39 Hot Pixels

    Quote Originally Posted by EH21 View Post
    Just curious, how long an exposure are you doing in your tests? At base ISO and short exposures, I'd expect to not see any hot pixels after opening in Phocus, but at higher ISO and long exposures you may seem some. One question is do they always appear in the same spots or random?
    Thanks for the follow up. I double checked the firmware and I am up to date with version 267. I went ahead and did a little stress test from ISO 50 to ISO 800. All 1 second exposures with the lens cap on. On the back the hot pixels really start to show up at ISO 100, and get progressively worse up to 800. If I zoom in the pixels start to disappear so I assume this is the cameras calibration file doing its job. When I open the files in Phocus the hot pixels pretty much all disappear even on the ISO 800 file. So the software is doing a good job of masking the hot pixels and I am satisfied with the final images coming out of Phocus.

    But my question still remains, is it normal to have so many hot pixels? Is this an abnormally high number of hot pixels for an ISO 100 file (the original image was shot at ISO 100)? Others on the web are claiming no hot pixels or very few (less than 10), I just want to make sure I didn't buy a back that is outside of normal standards?

    Thanks for the help!

    Tony

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    Subscriber & Workshop Member GrahamWelland's Avatar
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    Re: CFV-39 Hot Pixels

    I don't have the Hasselblad but with my IQ160 if I shoot longer than a minute at any ISO I'll see a disturbing number of hot pixels on the LCD but virtually none when I load the image in to either C1 Pro or ACR.

    What are you seeing with real non-lens cap images?
    Remember: adventure before dementia!

    As Oscar Wilde said, "my tastes are simple, I only like the best"

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    Re: CFV-39 Hot Pixels

    Quote Originally Posted by GrahamWelland View Post
    I don't have the Hasselblad but with my IQ160 if I shoot longer than a minute at any ISO I'll see a disturbing number of hot pixels on the LCD but virtually none when I load the image in to either C1 Pro or ACR.

    What are you seeing with real non-lens cap images?
    Pretty much the same thing, in the darker tones they stand out and in lighter tones they are just a little harder to spot. I have a call in to Hasselblad to see what they think and what my options might be.

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