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Thread: Is it normal noise for Aptus 22 @ 32 sec?

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    Member itsskin's Avatar
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    Is it normal noise for Aptus 22 @ 32 sec?

    I've read that Aptus 22 should be capable of delivering clean files at 30 sec exposures. Is it considered clean enough to leaf? To my eye - not so much.

    http://i382.photobucket.com/albums/o...sskin/1031.jpg

    Thank you!

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    Senior Member yaya's Avatar
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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    Looks OK to me for a 50iso file and should clean nicely with either the "clean long exposure" tool in Leaf Capture or the "Single Pixel" slider in Capture One.
    If you bring it down to 25iso you will get far fewer hot pixels.

    Yair
    Yair Shahar | Product Manager | Phase One | Mamiya Leaf
    e: [email protected] | m: +44(0)77 8992 8199 | yaya's blog

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    Member itsskin's Avatar
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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    Thank you very much! It clear up the situation for me.

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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    well.. it is CCD sensor and its more than 8s.. they don't really ever do uber-well with super long ones.. Basically you just still forced to fall back to film with super long exposures.

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    Senior Member ondebanks's Avatar
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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    So the Aptus backs don't have internal dark-frame subtraction?

    Ray

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    Senior Member mediumcool's Avatar
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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    Quote Originally Posted by itsskin View Post
    I've read that Aptus 22 should be capable of delivering clean files at 30 sec exposures. Is it considered clean enough to leaf? To my eye - not so much.

    http://i382.photobucket.com/albums/o...sskin/1031.jpg

    Thank you!
    I have only done long exposures a few times on my A22; found that 12 seconds is my limit, and that was on night-time architecture, where noise was mostly visible in the highlights (dark noise)!

    Do not believe the 30 seconds bit.

    Will look for a file

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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    Quote Originally Posted by ondebanks View Post
    So the Aptus backs don't have internal dark-frame subtraction?

    Ray
    They do. This is evident because exposure takes twice as long as indicated if its longer than a few seconds.

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    Senior Member ondebanks's Avatar
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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    Quote Originally Posted by MarkoRepse View Post
    They do. This is evident because exposure takes twice as long as indicated if its longer than a few seconds.
    Thanks for confirming that.

    But it must be something that the user can opt for or not?

    Because if it cannot be opted out of, that means that what we're seeing in itsskin's linked image is the residual dark noise AFTER dark subtraction - which, if that were the case, is a truly scary amount of noise!

    Ray

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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    Quote Originally Posted by ondebanks View Post
    Thanks for confirming that.

    But it must be something that the user can opt for or not?

    Because if it cannot be opted out of, that means that what we're seeing in itsskin's linked image is the residual dark noise AFTER dark subtraction - which, if that were the case, is a truly scary amount of noise!

    Ray
    there is no magic bullet. Long exposure noise in underlit conditions is basically - random spikes in circuit that tries to see light in unfavourable condition and ends up with nothing. Different story when you got plenty of light (like shooting water with ND filters and stuff) - then you can go longer without as much noise. Night shots are worst.

    So even after dark frame trick - some noise will be present, unless of course firmware decided to throw stuff away. And you dont want that decision being made for you.

    On some cameras its very visible when dark frame was used - size of raw file suddenly ups to nearly twice as much.

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    Senior Member ondebanks's Avatar
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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    Quote Originally Posted by SergeiR View Post
    Long exposure noise in underlit conditions is basically - random spikes in circuit that tries to see light in unfavourable condition and ends up with nothing.
    A better description of dark noise is that it's caused by temperature-dependent generation of electron-hole pairs in the silicon; the electrons are attracted towards the anodes which trap them in the pixel wells. And you get dark noise whether or not there is any light flux present. The problem of course is that you cannot tell a "dark" electron from a "light" one, i.e. one which escaped the lattice by being elevated into the conduction band after absorbing a photon.

    But I digress...I'm not concerned here with the causes of dark noise; only its quantity in the Aptus sensors, whether their dark subtraction is optional?, and to what extent dark noise remains thereafter?

    Quote Originally Posted by SergeiR View Post
    So even after dark frame trick - some noise will be present, unless of course firmware decided to throw stuff away. And you dont want that decision being made for you.
    I agree - definitely not!

    Here's why I suspect that there was no dark subtraction done in itsskin's image. Normally the limitation of in-camera dark subtraction is that the temperature of the sensor keeps rising the longer it is active; so if the dark frame is taken immediately after the long exposure photo, it's taken at a higher average temperature. This produces too much dark current in the dark frame, so when it is subtracted, it over-subtracts, and hot pixels tend to end up zeroed or negative. But what we see here are lots of bright hot pixels.

    Ray

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    Senior Member yaya's Avatar
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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    As I mentioned in my first reply there are tools in both Capture One and Leaf Capture that can remove hot pixels completely or almost completely. Setting the back to minimum iso will also help as the signal is not being amplified

    And if you fancy seeing a clean 32 seconds 25 iso file just let me know....it's not a myth...

    Yair
    Yair Shahar | Product Manager | Phase One | Mamiya Leaf
    e: [email protected] | m: +44(0)77 8992 8199 | yaya's blog

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    Member itsskin's Avatar
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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    Yair, I do believe you, and soon will have my back to test

    BTW, what happens after 32 sec on iso 25? Let's say 2-3 minutes.
    Thank you!

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    Senior Member yaya's Avatar
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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    Quote Originally Posted by itsskin View Post
    Yair, I do believe you, and soon will have my back to test

    BTW, what happens after 32 sec on iso 25? Let's say 2-3 minutes.
    Thank you!
    Hi Ilya,

    After 32 seconds you get an error message and the image does not get recorded. There is no option to shoot anything longer than 32 seconds

    Best

    Yair
    Yair Shahar | Product Manager | Phase One | Mamiya Leaf
    e: [email protected] | m: +44(0)77 8992 8199 | yaya's blog

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    Senior Member ondebanks's Avatar
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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    Quote Originally Posted by yaya View Post
    As I mentioned in my first reply there are tools in both Capture One and Leaf Capture that can remove hot pixels completely or almost completely. Setting the back to minimum iso will also help as the signal is not being amplified

    And if you fancy seeing a clean 32 seconds 25 iso file just let me know....it's not a myth...

    Yair
    Yair,

    I'm still wondering: is dark-frame recording and subtraction optional in the Aptus backs? Or does it kick in automatically above some exposure-time threshold?

    Thanks,
    Ray

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    Senior Member yaya's Avatar
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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    It does it automatically beyond a certain exposure time. It's not optional
    Yair Shahar | Product Manager | Phase One | Mamiya Leaf
    e: [email protected] | m: +44(0)77 8992 8199 | yaya's blog

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    Senior Member Steve Hendrix's Avatar
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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    I try to be conservative when discussing long exposure expectations with digital backs, including the Aptus 22. But sometimes you need to re-visit things from time to time to refresh your impressions of those results. Like any long exposure-challenged device, the subject key and the overall exposure itself are important factors. These were taken last night with one of our $4,990 Aptus 22 units and developed in Capture One. All noise controls are off. There is a slight warm cast coming from the right side, but I believe that is due to a shaded light source from that side. This was shot with the Schneider 80mm, ISO 25, exposure of 29 seconds @ f/14. If anyone wants a raw file, PM me please.


    Steve Hendrix
    Steve Hendrix, Sales Manager, www.captureintegration.com (e-mail Me)
    Digital Cam: Phase One | Leaf | Leica | Sinar Authorized Reseller
    TechCam: Alpa | Cambo | Arca Swiss | Sinar Authorized Reseller

  17. #17
    Senior Member ondebanks's Avatar
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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    Steve,

    Did you do this to demonstrate the long exposure quality of the Aptus, or was it to show off your collection of coffee-table books?

    Seriously, I'll PM you about RAW files, thanks.

    Ray

  18. #18
    Senior Member Steve Hendrix's Avatar
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    Re: Is it normal noise for Aptus 22 @ 32 sec?

    Quote Originally Posted by ondebanks View Post
    Steve,

    Did you do this to demonstrate the long exposure quality of the Aptus, or was it to show off your collection of coffee-table books?

    Seriously, I'll PM you about RAW files, thanks.

    Ray

    Actually it was to show off my collection of cat beds! Just 2 of my 5, on top of the table, cat-less for the moment.


    Steve Hendrix
    Steve Hendrix, Sales Manager, www.captureintegration.com (e-mail Me)
    Digital Cam: Phase One | Leaf | Leica | Sinar Authorized Reseller
    TechCam: Alpa | Cambo | Arca Swiss | Sinar Authorized Reseller

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