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Learning curve: Difference in Color vs. B&W ISO capability & noise

Discussion in 'Black and White' started by roundball, Aug 28, 2016.

  1. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    USA
    Experimenting more and more with B&W and have been impressed with its better noise-free results SOOC than with color...at least on the NEX7 model.

    To minimize / try to eliminate noise shooting color, I either have to use base ISO100, or use ISO200/400 when there is NOT a lot of dark areas in the scene which usually show a lot of noise.
    (in spite of having hi ISO noise reduction turned on)

    But I can routinely use ISO800 shooting B&W and the results seem noise free and tack sharp SOOC...including pretty dark shots around 10-11 o'clock at night with only faint distant light from a yard light bulb.

    In trying to understand this better, I've read that the absence of color pixels in B&W photos is responsible for that...was wondering if others agree and/or have additional information?
     
  2. WestOkid

    WestOkid TalkEmount All-Pro

    Jan 25, 2014
    New Jersey, USA
    Gary
    Well the camera's Bayer sensor is always capturing in color so the noise captured is the noise captured. I don't know about the Nex 7's noise reduction programs. Maybe they don't do so well with color noise. I'm not sure. That said, the issue maybe be less technical and more about human perception. Basically noise in B&W photos resemble film grain. This type of noise is less of a distraction and more acceptable to the eye.
     
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  3. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    USA
    To be sure I'm being clear, I'm not talking about "shooting color" then flipping it to B&W...in those cases the color was captured but then suppressed or something during the conversion to B&W I guess.

    Shooting native B&W with the camera actually set to B&W, I understood no color was captured...and as a result of that for example, there's no way to convert a B&W image in the other direction...to a color image...because the color wan't captured in the original B&W image to begin with ?
     
  4. JMM

    JMM TalkEmount Regular

    43
    Jul 29, 2016
    John
    There is bayer color filter grid in front of your matrix. Like nd / uv / gradient filters on your lens. So you can't take "real" bw photos with any color camera. On the other hand, if you REALLY want to, you can remove that filter by scratching it off - but it's one way trip. However it should boost your BW resolution and iq quite a lot.
     
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  5. WestOkid

    WestOkid TalkEmount All-Pro

    Jan 25, 2014
    New Jersey, USA
    Gary
    I understood you. I think you misunderstand the process. There is no way for the camera to capture in B&W because it has a color RGB sensor. Each pixel captures either red green or blue. By selecting B&W all you are doing is telling the Camera's jpeg engine to do a B&W conversion of the color information. That is why if you set the camera to raw+Jpeg and shoot in B&W, you will see the raw is still in color.

    Just saw John answered too. Totally agree. The only digital camera I know of that comes with the color filter removed is the Leica Monochrome @ $6500.
     
    Last edited: Aug 28, 2016
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  6. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    USA
    Ahhhhh....makes sense...forgot about the Red/Green/Blue aspect of it to begin with.

    And just using JPEGs as I do...after the camera has converted all their pixels to B&W is why a JPEG B&W can't be flipped to color because while the color was originally captured, its no longer in the B&W image. Got it, thanks for taking the time to explain...
    :)
     
  7. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    USA
    And thanks for your reply as well...
    :)
     
  8. addieleman

    addieleman Passionate amateur

    Nov 13, 2012
    Netherlands
    Ad Dieleman
    Would that really work? The camera's software will still process the data as if it came from a sensor with a Bayer filter, even when the final result is a B&W jpeg. Therefore I also think B&W resolution won't increase from what it was in color. By removing the Bayer filter the light falling on the sensor is not attenuated anymore by the color filters so noise performance should improve. Anyway, I think I'll leave my A7's sensor stack alone :).
     
  9. JMM

    JMM TalkEmount Regular

    43
    Jul 29, 2016
    John
    My only modification to camera, was adding cooling and removing IR filter from 1100D. I wouldnt remove Bayer, (along with microlenses and AA filter), but there are people who did that, and some of them report sharpness increase. Still camera doesn't know about it, and will blend 4 pixels into one for final output. Real value beyond that modification is that it change spectral respone of those pixels - letting in much more light from whole VIS and some of UV (360+ nm) and IR spectrum. But that's for "astro-geeks".

    Edit:
    Example of superior resolution claim can be found here:
    B&W Conversion

    Tho i think it's been a bit exaggerated...
     
    Last edited: Aug 28, 2016
  10. Bill

    Bill TalkEmount Veteran

    339
    Oct 22, 2012
    Brisbane, Australia
    Bill
    Sensor noise is an interesting, complex and messy topic. There are a couple of pretty good discussions at Cambridge in Colour. I've shown the links below.

    For the sake of this discussion it's useful to divide noise into two categories: Luminance and Chroma. Luminance noise is the noise that can look a bit like film grain; Chroma noise is like splotchy colour.

    It's the Chroma noise, particularly, that can seem to reduce when an image is converted to B&W. So, yes, B&W has some inherent noise advantages over colour -- but, of course, you lose the colour.

    Digital Camera Image Noise: Concept and Types
    Image Noise: Examples and Characteristics

    On the issue of the Bayer filters: Even if you could remove the RGB filters from a colour sensor (and you can't in a practical way -- the E-Mount really needs its microlenses), I don't think it would be a good idea -- the Leica monochrome notwithstanding. Having that colour information in the Raw files means that we can do in post what we used to do with filters and B&W film. Having complete control over the colour responses is a wonderful tool when doing black and white.
     
    Last edited: Aug 28, 2016
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  11. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    USA
    Thanks for the info...

    Another thought I'll toss out FWIW...late one night learning / experimenting to shoot the Milky Way, I tried a few shots in B&W (NEX7) and was surprised how much more clear & sharp it seemed to be...as well as having to change the exposure time in Bulb.