Do lightroom presets that brighten images introduce noise?

Discussion in 'Image Processing' started by vtsteevo, Nov 28, 2012.

  1. vtsteevo

    vtsteevo Mu-43 Regular

    96
    Nov 20, 2012
    Hey guys, I am new to Lightroom and have always shot JPG. I am also new to my GX1 + 20mm.

    Tonight at a restaurant I shot a RAW+JPG in iAuto with f/1.7, 1/30, ISO @ 1600. The JPG looks fine, and if I do a straight export of the RAW out of lightroom it looks fine as well. I then started to play around with some presets - most of which brightened the image, which I thought made it look better. However it introduced a whole lot of noise. Am I doing something wrong, or is noise a side effect of fixing exposure issues in post processing?

    P.S. I am exporing at the JPG quality level of 76. Haven't uploaded the images yet b/c they are 9 MB each!

    Thanks,
    Steve
     
  2. Zariell

    Zariell Mu-43 Top Veteran

    535
    Sep 28, 2012
    Bountiful, UT
    Increasing brightness can introduce noise, especially in the shadows, you can do recovery with the noise filter in lightroom, but its better IMO to get the exposure right in camera, but as we all know thats not always possible.

    Just remember its a double edged sword, the lighter the image the more noise you introduce, and you can remove noise with NR but then you risk going the other way and making your image into a cartoon :p

    I try to keep the noise down by using the adjustment brush only on the parts of the image that need it, then I can do NR just to that part of the photograph.
     
  3. tanngrisnir3

    tanngrisnir3 Mu-43 Top Veteran

    594
    Oct 18, 2011
    Steve, you're asking questions that can't be immediately answered.

    Could you post the images you're talking about? That would pretty much put what you've shot up front and center.
     
  4. vtsteevo

    vtsteevo Mu-43 Regular

    96
    Nov 20, 2012
    I uploaded them to photobucket. Zariel, I will try the brush method. Which filters are you referring to though?

    RAW with no processing
    P1060030.
    Some processing
    P1060030-2.
    A bit more extreme
    [​IMG]
     
  5. Zariell

    Zariell Mu-43 Top Veteran

    535
    Sep 28, 2012
    Bountiful, UT
    I think based on the noise, high ISO you are underexposing in camera, next time try to meter a bit differently and check your histogram, that being said...

    Under your develop settings you can choose the adjust brush, following that you can paint in the areas you want to lighten using either exposure, highlights, and shadows, then you can adjust the noise settings for the same part of the image you are playing with.

    For a whole image adjustment, go into the detail tab, which will allow you to adjust noise either in luminance or color noise zoom into 100 percent and then adjust till it has a better look, I could go into a ton of settings here, but I would say the best is to learn by doing :p Nice thing about LR is your settings on raw are completely non destructive.

    Unfortunately I think the best advice is either to try to shoot with a lower ISO, and or checking your histogram and getting more exposure time to lessen or eliminate the need to post process is reduced. :p

    Hope my rambling helped some, keep on keeping on!
     
  6. elavon

    elavon Mu-43 All-Pro

    Sep 1, 2012
    Tel Aviv Israel
    Ehud
    In electronics, noise is a random fluctuation in an electrical signal cause for two adjacent pixels that represent the same color to have slightly unobserved different value.
    When we increase the brightness or contrast the two adjacent pixels get slightly larger different value that cause us to see the difference.
    In short the change of brightness only cause us to see the noise which is hidden in the picture.
     
  7. vtsteevo

    vtsteevo Mu-43 Regular

    96
    Nov 20, 2012
    thanks guys.. now I have an excuse to go to the same restaurant and request the same table so I can try out different settings :)
     
    • Like Like x 2
  8. dhazeghi

    dhazeghi Mu-43 Hall of Famer

    Aug 6, 2010
    San Jose, CA
    Dara
    Exactly. The corollary is that if you want less noise, you need to expose more - in terms of shutter speed, aperture or sensitivity.

    Especially with low-light pictures, if you don't want noise, you should always expose as much as possible, without either blurring the image (camera shake or motion blur) or blowing out important details.
     
  9. vtsteevo

    vtsteevo Mu-43 Regular

    96
    Nov 20, 2012
    Do you guys advise using exposure compensation (+-) feature on the GX1, or is the exposure compensation a feature equivalent to adjusting exposure in lightroom- aka an after-the-fact adjustment after the exposure itself has already been set?
     
  10. Zariell

    Zariell Mu-43 Top Veteran

    535
    Sep 28, 2012
    Bountiful, UT
    Exposure compensation will adjust the cameras settings during the photograph, I am not sure about Panasonic but you can do the following test, point your camera at a object in aperture or shutter priority and take note of the /f stop and shutter speed, then dial in compensation and once again check, you should find that they have changed to adjust for the amount of compensation you added.
     
  11. yekimrd

    yekimrd Mu-43 All-Pro

    Jun 14, 2012
    Cincinnati, OH
    Mikey
    Recovering shadow/underexposed areas does introduce noise. I suggest proper light metering in-camera. Just make sure that the darkest area where you want to recover detail is no less than -2 or -2.3 (the opposite also works for if you want to recover detail in the brightest spots like the sky except no greater than +2).
     
  12. vtsteevo

    vtsteevo Mu-43 Regular

    96
    Nov 20, 2012
    Ahh. I was thinking about it all wrong. I thought that by adjusting exposure compensation up (+), I wouldn't need to use as slow of a shutter speed, so the camera would adjust the shutter speed up. WRONG. I guess exposure compensation does the exact opposite, by adjusting it up I am asking the camera to decrease the shutter speed beyound what it metered, so the lens stays open longer and allows in more light.
     
    • Like Like x 1
  13. Zariell

    Zariell Mu-43 Top Veteran

    535
    Sep 28, 2012
    Bountiful, UT
    Now your cooking with gas! :)