Noise reduction

Started Mar 25, 2011 | Discussions thread
snostorm
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Re: Noise reduction
In reply to martweb, Mar 25, 2011

Hi Martin,

I've previously used NN, but switched to Topaz Denoise since V3, and V5 does a good enough job that I haven't looked for another program for this funcion -- and don't have any plans to.

I shoot jpeg, and with the K-5 I turn in-camera NR off and just process noise in post. I've found with some experimenting that the the great bulk of the K-5's noise in jpeg is due to in-camera sharpening, so I've just turned it down to -4. With this setting, I get a very close facsimile to a base, unprocessed RAW file at ISO up to about 12800.

At this speed fine low contrast detail is going to be lost to either the noise or NR, but I really didn't expect it to capture the same level of detail as ISO, so I'm not disappointed. Here are a couple of examples I've shot so far -- not great pics, but somewhat illustrative. . .

This one's at ISO 10K, handheld with the Sigma EX 180 DG APO wide open. Cropped and PP'd with PSPP X2 with Topaz Denoise and Topaz InFocus and downsized for the web.

This one's at ISO 12800 with the DA 18-250 f3.5-6.3 at 200mm wide open at f6.2. Cropped and PP'd with the same plugins. BTW I was focusing more on the nose to see if I'd get any nose leather detail at this speed.. .

Jeez, they even block image files from the "other forum".

The PP on these is considerably easier, and the results are better than anything I've previously shot with the K-7 at ISO 1250.

I like the Topaz Denoise because it smooths edges of relatively fine lines and doesn't add a "painted with a brush" or "hammered metal" look to the whole image. I've found a quick workflow with this is to try the presets, looking for fully clean textureless areas, then back down the overall strength untill I start to see some roughness appear. I then bump the Shadow adjustment which will usually take care of the remaining noise. I'll then look around for any chroma noise and take care of that separately -- the K-5 controls this side of the noise equation pretty well by itself.

Topaz InFocus is a pretty impressive program once you learn to use it. It allows deconvolution sharpening, micro contrast adjustment, and edge contrast sharpening, and you can adjust these separately. I generally use just the deconvolution and add some mirocontrast. Repeated small applications work better than a single large application.

These are good tools, IMO.

Scott

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