Steve'sDigicams

nv1983 · Dec 9, 2005, 6:08 PM

Hi,
I have just recently started using RAW file format with my rebel xt. I shot a picture at night and I accidentally left the camera on shutter priority so it was a bit dark. I later realized my mistake and took the same picture again. Now I'm converting the pictures to jpeg and was messing around with exposure compensation function and I think when I increase the compensation the noise in my picture also increases(the darker or underexposed one). Is this true or am just seeing things?? Also there is this function in the program that is called fill light would that add noise to my pictures. All my pictures were shot at iso 200 and I'm using rawshooter essential 2005 (great software)
thanks a lot,
nv

eric s · Dec 9, 2005, 6:35 PM

First off the words "exposure compensation" actually have meaning and its different than what you're describing. Exposure compensation is actually an action you take on your camera while photographing. It lets you make an adjustment (compensation) to the exposure the camera picks, correcting for the settings that the camera thinks are right for the given situation. Just thought I'd say that.

Adjusting exposure in the RAW conversion doesn't create noise but it will make it more visible. Most noise in a DSLR seems to be in the dark areas of the image, usually refered to as "dark noise". When you lighten the image the dark noise becomes more visible. So there is (to your eyes) more noise than there was before you took the image. It's just an illusion, though... there isn't actually more, what was there was made visible.

The "fill light" lightens only the dark parts, I assume? If so, it would also make the dark noise more visible. Increasing the brightness of the image after taking it isn't a magic thing with no concequences. The downside is that it makes the noise stand out more and costs you detail... and it just looks bad. You can do it some, but not a lot.

Eric

ps. That advice is camera dependent, of course. Some produce less dark noise and therefor you can lighten then more.

Setiprime · Dec 13, 2005, 10:23 AM

Even though EricS has only 5000+ responses he is sometimes correct. This is one of those times, and very well put.

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Dec 9, 2005, 6:08 PM	#1
nv1983 Member Join Date: Aug 2005 Posts: 32	Hi, I have just recently started using RAW file format with my rebel xt. I shot a picture at night and I accidentally left the camera on shutter priority so it was a bit dark. I later realized my mistake and took the same picture again. Now I'm converting the pictures to jpeg and was messing around with exposure compensation function and I think when I increase the compensation the noise in my picture also increases(the darker or underexposed one). Is this true or am just seeing things?? Also there is this function in the program that is called fill light would that add noise to my pictures. All my pictures were shot at iso 200 and I'm using rawshooter essential 2005 (great software) thanks a lot, nv

Dec 9, 2005, 6:35 PM	#2
eric s Senior Member Join Date: Dec 2002 Posts: 5,803	First off the words "exposure compensation" actually have meaning and its different than what you're describing. Exposure compensation is actually an action you take on your camera while photographing. It lets you make an adjustment (compensation) to the exposure the camera picks, correcting for the settings that the camera thinks are right for the given situation. Just thought I'd say that. Adjusting exposure in the RAW conversion doesn't create noise but it will make it more visible. Most noise in a DSLR seems to be in the dark areas of the image, usually refered to as "dark noise". When you lighten the image the dark noise becomes more visible. So there is (to your eyes) more noise than there was before you took the image. It's just an illusion, though... there isn't actually more, what was there was made visible. The "fill light" lightens only the dark parts, I assume? If so, it would also make the dark noise more visible. Increasing the brightness of the image after taking it isn't a magic thing with no concequences. The downside is that it makes the noise stand out more and costs you detail... and it just looks bad. You can do it some, but not a lot. Eric ps. That advice is camera dependent, of course. Some produce less dark noise and therefor you can lighten then more.

Dec 13, 2005, 10:23 AM	#3
Setiprime Senior Member Join Date: Sep 2003 Posts: 484	Even though EricS has only 5000+ responses he is sometimes correct. This is one of those times, and very well put.