Noise with a plolarizer?

[nakedyak]

Ive noticed that when using my polarizing filter, there seems to be a lot of noise in the darker areas. Here are some examples

20D, 17-40, F8, iso 100...so there shouldnt be any noise. this sample was a jpg, but i also shot it in raw, and the noise was still there. thanks

here's a closeup of what im talking about

 

[Big Mike]

Doesn't look very noisy at all, to me. You can see a bit of something...but it's not anything I wouldn't expect from any digital camera.

Also, noise seems to come out in dark/under exposed areas (which this is)...and noise seems to be more noticeable in solid color areas (which this is)...I think Red is the worst but blue isn't the best color to hide the noise.

 

[Alex_B]

it is an ultrawide angle so you underexposed some part of the sky considerably due to the polariser. i remember we discussed this a bit very recently somewhere on the forum *tries to remember*

anyway, underexposed areas of an image are always more prone to noise, even if you don't pull them brighter. it is not really bad for a digital camera.
was it a hot day? that might be able to raise nose levels as well a bit if the senor got really hot.

 

[nakedyak]

I don't think that area is necessarily underexposed, just darker due to the polarizer. Not a hot day, maybe 50s.

Just seems to be a little bit of more noise than I'd like...just wondering if its normal.

I was also using a UV filter with this shot

 

[Alex_B]

the filter should not make a difference.

ok, so that was not a hot day.

sharpening pronounces noise as well, but those don't seem to be oversharpened in camera. hmmm, not sure how much noise is normal on a 20D.

 

[Don Simon]

A UV filter and a polarising filter? I don't know if that would increase noise specifically but it certainly won't do you any favours. It's best not to stack filters unless it's necessary... and in this case it isn't, just stick with the polariser.

 

[nakedyak]

sharpening is set at 0...

i did just increase in camera saturation however, kind of ala Ken Rockwell...

I was under the impression that the 20d handled noise expertly. It's been my experience that it does anyway

 

[Alex_B]

i did just increase in camera saturation however, kind of ala Ken Rockwell...

ahhh.. that might be part of the clue then! that can increase noise!

maybe try setting that back to normal, do some noise reduction on your raw image and then increase saturation .. just an idea




infamous ken rockwell again ...:meh:

 

[Big Mike]

Yes, increasing the saturation can add a bit of noise.

I don't think that area is necessarily underexposed, just darker due to the polarizer

That doesn't matter to the camera...the area in question is dark...which can tend to show the noise.

Again, I don't think it's very bad at all...and maybe you are expecting too much, or being too picky. Viewing a shot at 100% on the screen is almost the same as making a large print and viewing it with your nose up to the paper. Of course you are going to see some imperfections...if it was shot on 35mm film...you would probably see the film grain.

If it does bother you, you can always increase the noise suppression or run it though a noise program like Neat Image.

 

[Alex_B]

if it was shot on 35mm film...you would probably see the film grain.

yes, een if i shoot on fine grain velvia, the grain would be at least what we see here... and then i use neatimage to get rid of it if it bothers me.

 

[nakedyak]

i will try a few things tomorrow like over exposing a little bit, reducing saturation in camera,, taking the uv filter off, etc