Noise, when it is acceptable?

Thusie

This question was asked of me about the photo linked below (used with permission). I do not do people shots so your thougts would be greatly appreciated.

claudermilk

Looks fine to me. Yeah, there's some visible noise in the pixel-peeping version, but in the full image it's not noticeable. It does appear that the sharpening has made it more harsh. If it really bothers you, I'd go back & reporcess; hit the image with some very mild noise reduction, then sharpen again.

Thusie

Chris,

Not my photo. This is a retorical question I think.

Duffy Pratt

The only relevant question is whether the noise is visible in the final display (print or web) under normal viewing conditions. And if it is, is it objectionable.

Pixel peeping to find noise, and then complain about it, is just a waste of time. There might be a reason to do it if you are going to do a big print, or do a very severe crop. But noise, unless its visible in the final print, is not a problem on its own.

Now suppose you do have some visible noise in the print. Then the question becomes how much it hurts the image. Here, it hurts the image some, to my eyes, in the big crops. You might not get the same result from a print of those crops. And even here, I don't think the crop noise is _that_ bad. But I tend to have more tolerance for a grainy look.

Duffy

Thusie

Thanks Duffy

rutt

This is my shot and I encouraged Thusie to post it along with her question about noise. I'm only just getting around to following up.


Duffy and Claudermilk basically answered the question the way I would. But I was already thinking about it, so perhaps I have something to add.

There is no single answer to the question "when and how much noise is acceptable?" It depends on the one's goals.

Personally I think a picture should look good in totality. That means it should look good when you are far enough away from it to see it all or when it's at a magnification where you can see it all on the computer screen. That guideline means you can tolerate more noise than if you insist on looking at a detail of the image. Sharpening is very much the same. You sharpen so the whole image looks good. Blow up just a section and you'll see the artifacts (halos in the case of sharpening.)

Think about impressionism. Those brushstrokes disappear when you step back from the picture enough to see the whole image. Well, no disappear, but you don't see them exactly. They give it character. Think about Seurat or Cartier-Bresson.

Did you ever shoot tri-x? Grain (which is just noise in film) isn't all bad. The worst thing about it is how it interacts with sharpening, IMHO. That can look really bad and I'm always fighting it in the ballet shots. Bob was shot inside at ISO 1600, and I didn't do the same things I do to fight the noise in the ballet shots, so I suppose there is noise. Truth to tell, I don't mind showing the sun damage on his skin. It's part of him. If I were being kinder, I would have:

1. Used a surface blur early in the process to make his skin smoother, and
2. Used the blend-if sliders when sharpening late in the process to keep a the conventional USM away from his skin (exclude yellow).

Truth to tell, probably this wasn't my best post work. Certainly not the most careful. I did iton my notebook in bed while watching TV. Still, looks pretty good to me, actually. I like the composition and I like how it captures Bob's involvement with the wine. If I cared a lot about the noise, I could redo with the steps I outlined for you and it would look different and less noisy. Better? Maybe.

Anyway, that's what I would have said if Duffy and Claudermilk hadn't said it more tersely first.

pathfinder

I think the first image looks just fine, John. Is there slight visible noise looking at the whole image? Maybe a little, but certainly not enough to whine about.

Can you see noise when looking at the tight crops ? Of course, but so what.

I suspect that a print up to 8x10, or larger perhaps, will not show significant noise at typical viewing distances.

The grain is no where near what we used to see with 35mm color negative film.

gus

Sorry but i see it all differently. Over think this sort of stuff & it can ruin a damned good hobby.

saurora

Noise can distract and noise can enhance. It certainly depends on the image and as Rutt said, the goal of the photographer. If one is shooting a bird against a blue sky, normally grain is a distraction and does not add to the shot. But portraiture of all types often benefit from the enhancing qualities of noise. I definitely am reminded of impressionism when used in this way. Landscapes and still lifes also can be beautifully rendered and enhanced by noise. New born babies? You betcha....noise can soften and disguise skin problems on older subjects as well. While it is admirable (and desireable) to be able to shoot noise-free, due to knowing how to obtain good exposures, proper lighting and good ps skills, it can be limiting (in my opinion) creatively to not know how to use noise to your advantage. To me noise helps create atmosphere and mood and is more often a tool than a problem. To answer your question as to when it is acceptable, I'm not sure there are any rules, but if there are they are meant to be broken!!!

gluwater

I find it interesting that no one has mentioned color noise. There is no color noise in your image, did you reduce this in ACR? In certain images I do not find noise to be an issue, but I do find color noise to be very distracting. B&W noise looks like film grain more or less, color noise looks "digital" and is not very attractive. As saurora pointed out, I think it depends on the image. Nature, landscapes, and macro are three areas that should be noise free for the most part.

gus

The goal of the photographer is to get the shot...the rest is for the pixel counters. Almost every page of the many nat geo's laying all about my joint has shots with average light...a good amount of noise etc etc. But its the story that sits with the shot that matters to me.

z_28

I didn't read all posts, sorry, no time.
But picture looks perfectly fine.
If some noise reduction required - why not - that's just 10 seconds of work.

Thusie

What a good idea to put this up Rutt. No the noise in the shot didn't bother me. Noise can bother me and it is most often because the shot has so many other issues noise adds insult to injury.

On the flip side there are some so freaky about noise they run it though noise reducers to the point that while butter smooth there is no detail and it looks plastic.

pathfinder

rutt

I've been meaning to redo my ballet post tutorial (which I think should be good for any professionally lit theater shots.) These days I add some steps to handle noise early in the process, which I do entirely so that I can sharpen them more toward the end without ending up with big white dots on the dark backgrounds and (worse) dark facial features like eyebrows.

So here is one technical answer to Thusie's question: noise is unacceptable when it prevents you from doing as much sharpening as you want.

I don't think that's exactly what she was looking for, but it is an objective answer.

rutt

gus wrote:

The goal of the photographer is to get the shot...the rest is for the pixel counters. Almost every page of the many nat geo's laying all about my joint has shots with average light...a good amount of noise etc etc. But its the story that sits with the shot that matters to me.

Gus, I agree with this sentiment wholeheartedly. But something seems to be bothering you that's deeper than this. Can you be more specific, please?

Thusie

rutt wrote:

So here is one technical answer to Thusie's question: noise is unacceptable when it prevents you from doing as much sharpening as you want.

I don't think that's exactly what she was looking for, but it is an objective answer.

Right on objective! and I love it!

saurora

rutt wrote:

I
So here is one technical answer to Thusie's question: noise is unacceptable when it prevents you from doing as much sharpening as you want.

I don't think that's exactly what she was looking for, but it is an objective answer.

That observation works very well for me. The noise has to be acceptable to begin with since the sharpening will magnify it. When you are not looking to add noise, but you want a clean shot and plan to sharpen, it's very annoying. I worked on 2 images last night that were shot at the same time, same place, same exposure. One image insisted on being noisey and not being very advanced in PS skills I momentarily wondered why that was. But, like Gus, I don't usually over obsess about it. On the other hand, I would like to be a good enough photographer to know how to control it when desired.

Duffy Pratt

I basically agree with Rutt. But while his maxim may make the evaluation of noise "objective," it still leaves lots of wiggle room in the idea of the amount of sharpening "you want."

Also, there are types of noise that don't have too much to do with this idea. With my camera, shooting at night with high iso will lead to lots of color noise. The impact on sharpening isn't the problem with this noise. It's the noise itself that is the problem.

Duffy

rutt

Duffy Pratt wrote:

Also, there are types of noise that don't have too much to do with this idea. With my camera, shooting at night with high iso will lead to lots of color noise. The impact on sharpening isn't the problem with this noise. It's the noise itself that is the problem.

Duffy

I don't get much color noise shooting with 5D or 1DmkII (well before I sold it.) Dan is all ready for color noise in the LAB book. Does that stuff work for you?

gus

rutt wrote:

Gus, I agree with this sentiment wholeheartedly. But something seems to be bothering you that's deeper than this. Can you be more specific, please?

You dont agree with it at all.

Duffy Pratt

Rutt,

In Shanghai last year I took some night shots at 1600 ISO with my 20D. I didn't have a tripod with me. The LAB techniques worked some in getting rid of the color noise I had in the dark sky. But it was so extreme that I had to do some serious LAB work with blend if sliders to kill the bad sky noise. (I'm used to seeing blue, but this night sky was filled with random red pixels).

For less arduous stuff, I have had really good results using the LAB techniques, especially when I was shooting JPG and getting lots of blue noise. Now that I'm shooting RAW, its less of an issue, because I use the ACR tool when needed, and the color noise has not seemed to be as bad in RAW files as it was in the JPGs.

Duffy