Noise problem...

Discussion in 'Beyond the Basics' started by KhronoS, Oct 23, 2008.

  1. KhronoS

    KhronoS TPF Noob!

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    So i recently started to retouch a lot of photos. And i have noticed on a lot of them a huge amount of noise even at very low ISO.
    Here is an example. A full size crop from a RAW image which was taken by a Canon 40D mounted with a 50mm lens at f/11 shutter speed 1/60s and ISO 200...
    Is this noise normal? I mean give me a break it's a 200 ISO :|

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  2. tirediron

    tirediron Watch the Birdy! Staff Member Supporting Member

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    Was this area brightened at all?
     
  3. SilverGlow

    SilverGlow TPF Noob!

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    Is the posted image brighter then the original raw? I suspect the noise is there because of a bad exposure (under-exposed then later "fixed" in post)...perhaps the worse thing one can do is intentionally under-expose digital captures...even at low ISO's doing so will cause a noise problem.

    Better to expose to the right of the histogram, which will mitigate the noise, expand the dynamic range possabilities, and provide more subtle details and nuances in the shadows....never jugdge the exposure by the camera's lcd picture...it often lies and the look is at the mercy of the lcd brightness setting and ambiant light.....far better to judge exposure by the histogram. Raw images exposed to the right are "normalized" later in raw conversion (post processing).
     
  4. KhronoS

    KhronoS TPF Noob!

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    No, i didn't fixed the exposure in the photograph.. i think i have from mistake sharpened it... might emphasize the noise, but the fact is that there is noise at very low ISO.... but... there is a but... you might be right, i tend to see the extra noise in poorly lit areas...

    And it tends to be for example a lot of noise on the blurred background caused b the DOF, and the portrait to be with poor noise...

    Don't know, might be this case special... and a bit exaggerated... but for a long while i kept shooting and reviewed without seeing it at full size... and now i was struck by a whole lot of problems...
     
  5. SilverGlow

    SilverGlow TPF Noob!

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    During raw conversion or as the very first thing you do after conversion, mitigate the noise as required. To do this in the middle or as the last step of your post processing will only lower image quality.

    Here is what I suggest: I create a dup layer in photoshop, then apply anti-noise on that new layer. Then create a mask and fill it with 100% black, then paint in white ONLY in those parts of the image that need noise removal, but be careful not to paint away too much image detail.

    As to applying sharpness, do it surgecally: Flatten the layers made thus far, then create a duplicate layer and make sure you do this as the LAST step of your post processing tasks. Add USM to that new layer, then create a mask and fill it with 100% black. Then using white, paint in sharpening ONLY on the places on the subject that need it like the eyes, a bit on the teeth, frontal hair, all composition dependent. NEVER sharpe the bokeh, the background out of focus areas...this will only whip up noise and make the background look course instead of buttery smooth as it should be.
     
  6. Overread

    Overread has a hat around here somewhere Staff Member Supporting Member

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    I agree with silverglow regarding the editing - tis what I do when I do a proper edit, though sometimes I can get away with shots that don't warrent such editing - I can say nearly all my macro gose through this as noise and darker areas can crop up a lot more.
     
  7. KhronoS

    KhronoS TPF Noob!

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    I agree with you guys, and i think i have learned something... thank you very much guys :D

    I think that it was the sharpness combined with the underexposed background :) Now i will be more careful and work only with parts of image to sharpen/noise reduce...
     

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