What causes noise? - DPChallenge Forums

Olympus OM-D E-M5 Mark III

02/09/2009 10:01:22 PM · #1

I shoot with a Canon 40D and use DPP for post processing, sometimes elements 6. Almost always shoot RAW. I find, however, that while I usually begin with a properly exposed image that I invariably end up with an overly noisy image once its processed. Even when I shoot 100 to 400 ISO images.

I'm wondering if certain adjustments push more noise than others. Such as saturation adjustments, etc. And then how far is too far to push something? For instance, does pushing the fill light to 70 cause noise, I tend to bump contrast adjustments to 75, how about clarity, etc.

Yo_Spiff

Olympus 12-100mm f/4.0 M.Zuiko ED IS PRO

02/09/2009 10:22:16 PM · #2

Most of those adjustments brighten and highlight the differences between colors, so they do tend to start showing noise if taken too far. Especially the clarity (clariFy for PSP users like myself)

Message edited by author 2009-02-09 22:22:24.

scalvert

Canon EOS-5D Mark III

02/09/2009 10:31:02 PM · #3

Fill light is probably the worst offender since it's pushing up the shadow tones, where camera sensor tend to be weakest. You'll get less noise if you overexpose ever-so-slightly and recover the highlights.

zeuszen

Canon EOS-1Ds Mark II

02/09/2009 10:39:28 PM · #4

Originally posted by scalvert:

...You'll get less noise if you overexpose ever-so-slightly and recover the highlights.

That's the consensus, but the recovery usually does not return any detail. I prefer to underexpose and have a chance at a darker ambience in an image without any visible defects.

Message edited by author 2009-02-09 22:39:46.

Olympus OM-D E-M5 Mark III

02/09/2009 10:54:56 PM · #5

I guess it would be helpful to know what's too much. For instance, I've picked up that boosting saturation can lead to noise, but how else are you supposed to make colors pop in a RAW file? And if clarify pushes noise, then when does it start to become a problem. And so on. Are there typical limits?

In most cases I'm starting with a pretty good exposure and just tweaking to make the RAW file "pop" if you will and I never really end up with a vibrant, pin sharp clean file. Not like many of the images I see on here.

And while I'm very familiar with the functions of the tool sets in DPP and PSE, I guess its more of a workflow and understanding their limits problem that I have. Very frustrating because, (I think) it keeps a good image from being great. Hope that makes sense.

Message edited by author 2009-02-09 22:56:06.

Yo_Spiff

Olympus 12-100mm f/4.0 M.Zuiko ED IS PRO

02/09/2009 10:59:11 PM · #6

Can you post a couple of the images that are problematic for you, with exposure info?

cpanaioti

Canon EOS-40D

Canon EF 70-300mm f/4.5-5.6 DO IS USM

02/09/2009 11:13:25 PM · #7

Originally posted by Yandrosxx:

Too far depends on the photo. Too far in one image may not be enough in another. And it also depends on the person doing the adjustment. Too far for one person may not be enough for another.

The curve is usually where I start when adjusting a RAW file, then move to clarify, saturation etc. as needed.

02/09/2009 11:24:03 PM · #8

How does one post a thumbnail? Or, if I post a pic at 500 pix one side no more than 30k will that show up well enough?

zeuszen

Canon EOS-1Ds Mark II

02/09/2009 11:40:12 PM · #9

Originally posted by Yandrosxx:

View the file at hand at 100% when you're making changes to see how an adjustment effects the detail. Toggle to screen view to see the overall effect.
At 100% zoom, the appearance of artifacts will indicate precisely where and what "too muc"h is.
At screen view, you likely make aesthetic choices.

MelonMusketeer

Nikon D7000

Nikon MF 50mm f/1.4

02/09/2009 11:46:28 PM · #10

Originally posted by Yandrosxx:

How does one post a thumbnail? Or, if I post a pic at 500 pix one side no more than 30k will that show up well enough?

Open the photo in your DPC portfolio, then copy the 6 digit number at the end of the URL (http: bla bla 6 digits . )
Next open the thread you want it in, and click the "Reply" button.
Using the next to last icon button just above the text box, enter the 6 digit number in the pop up box.
Use the preview button under the text box to make sure that you have the right image number if you want to make sure before you post in the thread.

02/09/2009 11:51:58 PM · #11

But Zeus, that's really the problem. THey don't tend to show when viewed in DPP. The noise shows in the converted file. They always look pretty good in DPP. It's the converted JPEG/TIFF that looks bad.

zeuszen

Canon EOS-1Ds Mark II