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Thread: Is A900 14 bit ? What about crop frame lenses?

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    Is A900 14 bit ? What about crop frame lenses?

    B&H specs. say the A900 is 14 bit A/D conversion ... is that correct and what does it mean? I thought that 14 bit is what differentiated the D3X from the A900 ??????

    Also, there are some interesting lenses for the crop frame cameras, but it appears that they can be used on the A900 since APS-C crop seems like an option available. Is this just a jpg option? Does the A900 automatically recognize the DX type lenses?

    Anyone ever used the Siggy 20/1.8 (30/1.8) or 24/1.8 (36/1.8) digital crop lenses? Not that I'd necessarily get one, just curious because of the speed.

    What about the Siggy 70/2.8 full frame macro? It's low dispersion and floating lens design with 1 to 1 ratio?

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    Re: Is A900 14 bit ? What about crop frame lenses?

    The Sigma 20/1.8 and 24/1.8 (and the 28/1.8) are full frame lenses. I've used the 20mm sporadically on a crop sensor camera a couple of years back, and although somewhat soft wide open, it was absolutely usable. I suppose it will be even softer on a full frame camera. If you need the speed, there are no alternatives though.

    The Sigma crop lens in the range you mention is the 30/1.4.

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    Re: Is A900 14 bit ? What about crop frame lenses?

    Marc, I have read that the A900 is a 12-bit camera, but I cannot find any evidence of it now, even on dpreview. In any case, 12 is enough to contain the dynamic range, and I haven't heard of anyone seeing posterization in the images, so I guess it doesn't hurt.
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    Re: Is A900 14 bit ? What about crop frame lenses?

    For any Aps-c lens that the A900 recognizes a lens i.d. for, the A900 automatically crops in aps-c mode. This mostly just pertains to Sony/Minolta lenses afaik, and aps-c Sigmas can be shot in FF mode with vignetting.

    A900 is 12bit. There real question is about the D3x's 14bits. The most accepted theories right now are that the D3x simply oversamples or does multiple sensor reads to get 14bits from the 12bit ADCs, and that's why the fps are so low in 14bit mode. Whatever the method, it works, and the D3x has incredible DR. Last month, Iliah Borg said that he has been testing blue and red channel preconditioning in the A900, and he believes that it could give the A900 even better DR than D3x (he owns both cameras,) so Im REALLY hoping Sony pays attention to the tests he sends them, because that would be a sweet firmware upgrade.

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    Re: Is A900 14 bit ? What about crop frame lenses?

    p.s. Fwiw, even the best prime lenses can't handle more than 12 stops of DR (zooms even less so,) so we're already nearing the practical limits of camera DR, unless there is a significant jump in lens technology.

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    Senior Member Braeside's Avatar
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    Re: Is A900 14 bit ? What about crop frame lenses?

    Thanks for answering that Douglas, you beat me to it and probably explained it a lot better than I was attempting to.
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    Re: Is A900 14 bit ? What about crop frame lenses?

    Here is my teeny bit of A900 knowledge....The framelines for APS-c are the four little corners on focus screen in the viewfinder.

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    Re: Is A900 14 bit ? What about crop frame lenses?

    Last year I did some tests on a Nikon D300 to compare 12-bit and 14-bit mode. On that camera there was a slight difference, but I had to dig extremely deep into shadows to visually see the difference. I find it hard to imagine a photograph where it would make a difference unedited. Using tonal adjustments it could possibly matter in rare cases.
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    Re: Is A900 14 bit ? What about crop frame lenses?

    Quote Originally Posted by Lars Vinberg View Post
    Last year I did some tests on a Nikon D300 to compare 12-bit and 14-bit mode. On that camera there was a slight difference, but I had to dig extremely deep into shadows to visually see the difference. I find it hard to imagine a photograph where it would make a difference unedited. Using tonal adjustments it could possibly matter in rare cases.
    Not that rare if you intentionally (or unintentionally) underexpose. F.e. when top useful ISO of a camera is reached and farther increase will produce more noise than pushing underexposed shot in converter.
    Overall 14-bit is useful - gives more meat for processing. They just need to figure how to use it without affecting camera performance that much.

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    Re: Is A900 14 bit ? What about crop frame lenses?

    Quote Originally Posted by douglasf13 View Post
    For any Aps-c lens that the A900 recognizes a lens i.d. for, the A900 automatically crops in aps-c mode. This mostly just pertains to Sony/Minolta lenses afaik, and aps-c Sigmas can be shot in FF mode with vignetting.

    A900 is 12bit. There real question is about the D3x's 14bits. The most accepted theories right now are that the D3x simply oversamples or does multiple sensor reads to get 14bits from the 12bit ADCs, and that's why the fps are so low in 14bit mode. Whatever the method, it works, and the D3x has incredible DR. Last month, Iliah Borg said that he has been testing blue and red channel preconditioning in the A900, and he believes that it could give the A900 even better DR than D3x (he owns both cameras,) so Im REALLY hoping Sony pays attention to the tests he sends them, because that would be a sweet firmware upgrade.
    Where is the info about the A900 being 12 bit? ... I can't seem to find it anywhere, on any review or spec sheet.

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    Senior Member douglasf13's Avatar
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    Re: Is A900 14 bit ? What about crop frame lenses?

    Good point, Lars. From what I understand, Nikon has tweaked their 14-bit method with the D3x since the D300, and there is a bit more of a difference between 12 and 14 bit. However, like you said, who knows what kind of files and/or manipulations it takes to see such differences??

    Marc, I don't believe that Sony themselves list this stat, unfortunately, so we have to rely on reporting from places like Imaging Resource. Also, you can tell by analyzing the raw data to see how many levels that it has.

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    Re: Is A900 14 bit ? What about crop frame lenses?

    Quote Originally Posted by hardloaf View Post
    Not that rare if you intentionally (or unintentionally) underexpose. F.e. when top useful ISO of a camera is reached and farther increase will produce more noise than pushing underexposed shot in converter.
    Overall 14-bit is useful - gives more meat for processing. They just need to figure how to use it without affecting camera performance that much.
    Sort of like Nikon's Hi-1/Hi-2 ISO settings then, which essentially just underexpose with 1 or 2 stops to reach 12800/25600 (on D3/D700)... yep that makes sense. Not really to get more DR into an image but to be able to extend sensitivity beyond the nominal settings of the camera.

    Of course that assumes that the noise floor is lower than 12 bits at highest ISO setting. On Nikon cameras it's not, however if D3x does multipass averaging in 14-bit mode then that would suppress the noise floor further down.
    Last edited by Lars; 21st May 2009 at 07:53.
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    Re: Is A900 14 bit ? What about crop frame lenses?

    Quote Originally Posted by Lars Vinberg View Post
    Sort of like Nikon's Hi-1/Hi-2 ISO settings then, which essentially just underexpose with 1 or 2 stops to reach 12800/25600 (on D3/D700)... yep that makes sense. Not really to get more DR into an image but to be able to extend sensitivity beyond the nominal settings of the camera.

    Of course that assumes that the noise floor is lower than 12 bits at highest ISO setting. On Nikon cameras it's not, however if D3x does multipass averaging in 14-bit mode then that would suppress the noise floor further down.
    From my down-to-earth standpoint it's always good to have 4 times more gradations in shadows even if DR is still the same. In highlights it's irrelevant if you have 2000 or 8000 gradations for the last stop - too much in any case. In shadows though it's a big difference if you got 4 or 16 gradations for some bottom photo stop - 16 means smoother transitions and some hints of details will show up better, especially if you start pushing them towards midpoint.

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    Re: Is A900 14 bit ? What about crop frame lenses?

    Quote Originally Posted by fotografz View Post
    Where is the info about the A900 being 12 bit? ... I can't seem to find it anywhere, on any review or spec sheet.
    Indeed. I wish they'd publish specs of their sensors as Kodak does. A lot of geeky info to think about
    A900 has 12 bits per pixel in uncompressed ARW files. This doesn't mean that ADC is 12 bit though - could be downsampled 14 f.e., can't tell for sure. Compressed ARW has only 11 bits of some non-linear data.

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    Re: Is A900 14 bit ? What about crop frame lenses?

    Quote Originally Posted by hardloaf View Post
    ... This doesn't mean that ADC is 12 bit though - could be downsampled 14 f.e., can't tell for sure...
    Ah, thanks for that distinction.

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    Re: Is A900 14 bit ? What about crop frame lenses?

    Regarding APS-C every one seems to forget that you can manually switch to APS-C from the menu with any lens. As Douglas said, the camera switches automatically with a recognizable lens.
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    Re: Is A900 14 bit ? What about crop frame lenses?

    Quote Originally Posted by hardloaf View Post
    From my down-to-earth standpoint it's always good to have 4 times more gradations in shadows even if DR is still the same. In highlights it's irrelevant if you have 2000 or 8000 gradations for the last stop - too much in any case. In shadows though it's a big difference if you got 4 or 16 gradations for some bottom photo stop - 16 means smoother transitions and some hints of details will show up better, especially if you start pushing them towards midpoint.
    So how much is enough then? That's what we have to decide on. Do we need 8 stops DR? Probably quite often. 14 stops? Hardly ever. Sure more is better but we don't want to pay for precision that makes no perceptible difference in the final image. I'm superhappy with 12 bits in my D700, to the point that I seldom pack that 3-stop ND grad anymore.
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    hardloaf
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    Re: Is A900 14 bit ? What about crop frame lenses?

    Lars,
    Quote Originally Posted by Lars Vinberg View Post
    So how much is enough then? That's what we have to decide on. Do we need 8 stops DR? Probably quite often. 14 stops? Hardly ever. Sure more is better but we don't want to pay for precision that makes no perceptible difference in the final image. I'm superhappy with 12 bits in my D700, to the point that I seldom pack that 3-stop ND grad anymore.
    This is not about DR. You are still going to have about the same usable DR with 12 or 14 bits, it's just that values within the range are measured with finer gradations with 14 bit ADC.

    You can't get 14 stops anyway - as far as I know modern photo lenses can't pass more than 11-12 linear stops even in a perfect lab environment. In real life I'd say 9-10 is all we can count on with good glass and proper hood. So we have our limit, let's say 12 stops. This means we need more than one gradation on the bottom stop and some space for noise. Couple of bits at least. It makes 14. Looks like 14 should be good, may be 15-16 for high end.

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    Workshop Member ptomsu's Avatar
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    Re: Is A900 14 bit ? What about crop frame lenses?

    Found this on the Sony Swiss Site - in German of course:

    http://www.sony.ch/lang/de/product/d...TechnicalSpecs

    Under Kamera it says A/D Konverter Bittiefe (Bit Depth) 12bit

    which confirms it is "only 12 bit.

    Now, I have used the D3 and the 5D2 which are both 14bit, but folks I can tell you - just NO difference in 98% of the cases. And I did not run into the rest 2%

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