Noise Reduction software

Diane_Miller · January 25, 2021, 8:23pm

Some very useful software has come out in the last few years for noise removal, and that has become increasingly important in wildlife photography with the higher ISOs necessitated by some of the popular new slower telephoto lenses.

In the last few years I’ve been happy with Topaz products, currently Denoise AI. But the other day I inadvertently shot a tree detail at ISO 20,000, just using the camera as a monocular to try to see if I had spotted a bird’s nest. It turned out to be an apparently natural mass of lace lichen but just for curiosity I tried Denoise AI on the extremely noisy image. There were some fine strands of lichen hanging down against the sky, and I was surprised to find the default setting of Denoise AI left areas of noise around some of them, even after I tried some tweaks to the amount and sharpening sliders.

The software has tabs for Denoise AI, AI Clear and Low Light. I had heard somewhere that AI Clear was an older algorithm, but I tried it and it did not have the left-over areas of noise. Neither did the Low Light setting.

These left-over noisy areas had been an issue in the past for me with earlier versions of the Topaz product but I hadn’t seen them in quite a while. So now I’ll look more closely and try the other tabs/modes if I encounter the problem.

So I’m just wondering about the experience of others. (I’d post the image but I deleted both the raw file and the .psd.) I always do denoise first thing into PS before any cloning or tonal adjustments might change the distribution of noise, and I try not to do raw adjustments that may boost noise in darker areas.

BrettOssman · January 26, 2021, 9:20pm

I use the feature to see all 4 approaches side-by-side. Most of the time I go with Denoise AI, but have selected others. I have only had isolated cases where none did the job. Oh, I almost always use the Auto settings, but have tweaked on rare occasions. I love Topaz’s tools.

Max_Waugh · January 26, 2021, 9:40pm

I’ve found the same thing happens on occasion with DeNoise, though the patches of noisy remnants often seem a bit random (similar tonal areas get “cleaned up,” but a random area of noise remains untouched). In certain cases, Clear and Low Light have worked when Denoise didn’t, though not always.

This is why I can’t buy into the philosophy I’m hearing more and more when discussing how well/poorly a sensor handles high ISO noise: “just throw it into Denoise!” I’d rather not use it as a crutch, because it’s certainly not foolproof (yet!).

Max

Diane_Miller · January 26, 2021, 10:08pm

I’m also curious how people handle the sharpening amount that is suggested. I’ve been pulling that slider all the way left and doing any sharpening on a copy of the denoised layer, using Topaz Denoise AI. There is so much variability in their “modes” that I have to wonder what the sharpening in Denoise AI is doing. But it doesn’t seem to do much at all, as far as I’ve tried to look at it – which is good as it doesn’t seem to give oversharpened artifacts.

The sharpening is at such a small-scale level that it isn’t of much use unless it’s a huge crop.

Jim_Zablotny · January 29, 2021, 2:44pm

The sharpening from Topaz DeNoise AI is heavy handed for sure. I have encountered the Sam ed issues with patches of noise with high ISO images. Sometimes, I will run it again with masking to selectively remove noise in the affected areas. Not fun and quite time consuming…Jim

terryb · February 26, 2021, 3:09pm

Hi, Diane. Good topic, and I’m interested in everyone’s thoughts and experiences,
I’ll give my input but should note I’m still very new at processing, and welcome any thoughts on my workflow. I generally do as much NR as possible on the RAW file in ACR. Doing so on the RAW file seems to affect the rest of the photo properties less. Once I’m happy with that, I’ll open it in PSE 2020 and do a few other functions (such as Unsharp Mask, etc.). I then save the PS file and run it through Topaz De-noise Low Light. I can usually get by with a manual setting of 10, or less. I don’t do any sharpening in Topaz. I can’t see that it helps. That’s my usual workflow, but if Low Light doesn’t seem to help, I’ll try one of the other functions. I’m still experimenting…

Diane_Miller · February 26, 2021, 8:37pm

@BrettOssman, @Max_Waugh, @Jim and @terryb , thanks for the replies. It is definitely it is best to minimize noise, and ETTR (exposing to the right as much as possible without blowing out whites) is a great help, as is keeping the ISO down. But the sweet spot is often a very shallow dip.

I have found several recent versions of Topaz Denoise AI (it is at 2.4.2 as of this writing) are significantly improved, and the current one seems to have fixed the issue of areas of remaining noise, if I compare the three modes. The sharpening also seems to have improved, and I will now sometimes use the default amount and not do Topaz Sharpen AI as a separate step. But every image is different.

And a comment for @terryb – One thing that I feel is very important for image quality is not to try to mix several approaches. The topaz algorithm is optimized for sensor noise but won’t be ideal if that noise has been tinkered with in raw conversion or with other techniques, or if the noise has been made uneven with cloning. (The edges of a cloning brush are normally soft and those areas of partial opacity will soften noise.) So I strongly recommend running Topaz Denosie first thing when you open the image in PS or PSE, and not do any NR in the raw stage, rather than doing denoise the last step after a lot of other things have been done. Then I would sharpen if necessary, and then do other work.