Not Your Everyday Banana

by Bart Arondson

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I've been at photography for a little over a year, and I primarily do landscape and wildlife/bird photography. Most of my work has been a learning experience so far, with few shots actually something that I believe is high enough quality to try selling.

As I've experimented, I've learned that the best times of day to shoot interesting shots (particularly for landscape) are in the mornings and evenings. At these times, light is lower, and I tend to have to increase the ISO to capture a proper shot. With landscapes, I have the option of exposing for a longer duration (or use an ND filter and expose for a considerably longer time, but that totally changes the game), and I don't have to increase ISO as much, but for wildlife, to get a shot with enough sharpness I often have to increase my ISO to 800, and in a very few occasions, 1600. As a result, I have very few shots that I've felt were "acceptable" due to lots of grainy noise.

My camera, the Canon 450D (Rebel XSi), does not have very good ISO performance, so 800 is not particularly good, and 1600 is pretty terrible. At least, this has been my gut feeling most of the time. I am wondering when noise is unacceptable in a photograph, and if there are tools (other than Lightroom) that are adept at removing noise without softening the resulting image so much that it is still unacceptable. I like to print at 13x19 (A+) size, so the sharpness and clarity of my shots shows through on my prints to a considerable degree.

Sample Images:

Iris
Figure 1: A macro shot of an Iris at 1600 ISO. Tried to shoot some that were in full sunlight, however wind forced me to reposition to flowers in the shade that were not moving, and I had to use ISO 1600. Looked OK on the camera, but the noise is extremely visible on screen, and shows up when printed. There are little details in the stamen that have been pretty much obliterated.

Finch
Figure 2: A shot of a finch near sunset, surprisingly shot at ISO 400. I had to shoot at the 400mm end of my 100-400mm, so the image was a tad soft to start with. The noise drowned out any of the feather detail that was left. I'm not really sure why this shot, at ISO 400, looks so grainy...most of my ISO 400 shots seem to be ok, and the noise is acceptable. This shot was cropped quite a bit before it was printed, and the noise was visible in the final print, although it wasn't quite as bad as the ISO 1600 shot of the Iris.

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Note: All sample images were shot in RAW...I rarely use JPEG outside of quick family or spur-of-the-moment stuff where I use an automatic mode. –  jrista Jul 25 '10 at 23:56
    
It's not directly related to the question, but flowers can be lit by flash most of the time. –  che Jul 26 '10 at 0:25
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Regarding the grain in the bird shot; the green channel carries most of the luminance information, which gives the noise in the green background more contrast. –  Guffa Jul 26 '10 at 0:26
    
@Guffa: Ah! That makes total sense. Digital sensors do have twice as many green photosites as red or blue, so it does seem logical that green would pick up more luminance noise. –  jrista Jul 26 '10 at 0:32
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Well, it's rather that the green channel has almost the same amount of noise. The sensor has more green diodes to catch more luminance information, this also helps a bit against noise, but not very much. The green channel has higher contrast than the red and blue simply because 100% green is brigher than 100% red or blue, and the higher contrast means that the green noise is more visible. –  Guffa Jul 26 '10 at 9:27
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8 Answers 8

up vote 11 down vote accepted

It totally depends - it's an artistic vision thing, and I don't think anyone but you can really answer it. That said, I've rarely encountered folks who were insufficiently concerned about noise; far, far more often people are more worried than they should be. It might be worth your while to have some third-party critiques of prints you're concerned about. Perhaps you could post an image here too?

Whatever you do, don't evaluate noise by zooming to 100%. It will look far worse than it really is.

Another answer suggested a B&W conversion - that can help dramatically in terms of noise mitigation.

Edit

Given the new samples, which appear to be at 1:1, I do wonder if you are falling into the 100% crop trap. Since you're most concerned with prints, I'd suggest circulating those for feedback - unfortunately, that's not something we can help with. :) But even non-photographer friends could help; get their initial impressions, and then ask them if they think it's too grainy.

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I'll see if I can get some crops of the photos I'm worried about. The problem is not quite as apparent at ISO 800, but ISO 1600 shows a lot of grain even when printed. Perhaps its not really a problem, but I do think I lose some interesting detail when it occurs, particularly in animal fur and bird feathers. –  jrista Jul 25 '10 at 23:37
    
I've added some sample crops to my OP. Both images were cropped a bit from the original size, then printed. The flower looks ok when printed at 4x6, but the desired 8x10 looks pretty grainy. The bird looked a bit grainy at 8x10. Perhaps that is ok though, if looked at from the perspective of it being an "artistic" element. I'll have to reevaluate my prints given that. –  jrista Jul 25 '10 at 23:55
    
@Reid: Regarding the 100% crop thing...most of my prints are at 13"x19", or A+ format. My 12.1mp camera's full crop size is just barely enough to print an unscaled (or rather, slightly scaled up) 13x19 @ 240ppi. Prints generally look ok at ISO800, however many of the more recent bird shots have been in the evening, and the grain from them is pretty pronounced even in the prints. I tend to crop the bird photos a fair bit, as I only have a 100-400mm telephoto, and I can't get quite close enough to really get the proper composition optically yet. Would you still consider that a "crop trap"? –  jrista Jul 26 '10 at 0:02
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@jrista: Your screen is 96 DPI and your prints are 2.5 times more tightly packed. That's the 100% crop trap, because you're not comparing reasonably as the density on your monitor doesn't even come close to the print. This is why I tend to post online somewhere around 25-35% from the original image as it approximates the same visual effect of a print (I also print between 11x17 and 13x19). If the image looks sharp there, it will very likely also do when printed. –  John Cavan Jul 26 '10 at 0:31
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@jrista, perhaps you need to go medium-format. Do you have $40-60,000 burning a hole in your pocket? :) –  Reid Jul 26 '10 at 22:57
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I was a big fan of Noise Ninja for the longest time until I got my hands on Topaz Denoise which produced remarkable results. I used to avoid 1600 ISO or higher for the longest time on my Pentax K20, but not any more.

Here's a sample of ISO 3200 after Topaz Denoise:

alt text

Here's the before (the change in colour is not related to noise reduction):

alt text

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Note, right click and view image to see the larger size. –  John Cavan Jul 25 '10 at 22:08
    
I guess we'd need to see the image before and after noise reduction to judge the change in quality. –  che Jul 25 '10 at 22:14
    
@che: There ya go! –  John Cavan Jul 25 '10 at 23:06
    
@John: Thank you! –  che Jul 25 '10 at 23:09
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Was that shot in JPEG or RAW? –  Dennis Williamson Jul 25 '10 at 23:44
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I guess it depends on personal taste. There surely are people which would claim anything above ISO 200 has unacceptable noise, while others are happy with low-light images from compact cameras which look like oil painting and still are significantly noisy.

If you feel your high-iso photos are unusable, feel free to avoid the settings, but it will cost you some amazing pictures you'd otherwise be able to make.

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Don't forget that noise can also be a creative tool. Especially when paired with black-and-white, high ISO noise can sometimes add a lot of atmosphere to the image. Some images need noise.

I'd say that the answer to your question is "as much as the image can take".

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How much noise/grain we accept is subjective, but there are at least some things we can say:

  • Film grain is something that we have lived with since the dawn of photography. Some like the effect, and even add fake grain to their digital images.
  • Film grain is mostly luminance differences, while digital noise is both luminance and color differences. If you reduce the color noise, digial noise looks more similar to film grain.
  • It's hard for noise removal software to tell the difference between noise and small details, so some detail will always be lost if you remove a lot of noise.

So, noise that look like film grain is generally more accepted. By reducing most of the color noise and some of the luminance noise, I think that you can reach a good compromise that doesn't remoce too much detail.

The I would like to add some perspective:

Even if you think that your camera doesn't have very good ISO performance, it's still a lot better than my first DSLR, the Canon D60. It was terrible at 800 and awful at 1000, and it didn't even go as high as 1600. Still I payed about five times as much for it...

Newer cameras are definitely pretty good at high ISO, both compared to older cameras and compared to film grain. If you compare the result from your camera at ISO 1600 with the grain in an ISO 1600 film, it's not very noisy at all.

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Thanks for the insight. Good to hear that the ISO performance of my 450D isn't too bad. I to like the look of film grain better than noise though...not sure exactly what it is...maybe the more random nature of it, and the dynamic size of the grains, since its based off of the size of silver halide clusters. Digital noise grain is all the same size. I do know that Lightroom 3 adds a film grain adder tool...I may give that a try once I upgrade. –  jrista Jul 26 '10 at 0:31
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There are two different kinds of noise, and they should be discussed separately: luminance noise and color noise.

The color noise is disturbing, unwanted and should always be avoided. Here's how it looks: color noise

Luckily, it's very simple to eliminate it without loosing details, so about any noise reduction software will do: no more color noise

(of course, this is an extreme example).

The luminance noise is completely another story. First of all, almost no image is possible without luminance noise. Computer screens and printers are not able to reproduce "ideal" color gradients without some random pixel jittering in it - the noise. Second, some media require additional luminance noise for better output: printers. Third, luminance noise psychologically adds sharpness to an image. Classic example of fake sharpness for a landscape is to add luminance noise to it. Fourth, luminance noise is almost never psychologically visible. I.e. common viewer will not pay attention to it, won't notice if it is there or not. To test, go check out AP or Reuters pics - lots of them have luminance noise but I bet you never noticed:)

Of course, if you have an extremely noisy picture, you will have to reduce luminance noise as well, but never too much.

In conclusion: fight color noise, leave luminance noise.

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Most of the answers here discuss noise removal in post-processing. My suggestion would be to do everything you can to avoid noise (if noise is not part of the concept) before you take the shot - good camera, fast lenses, VR/IS where applicable, stable tripod for landscapes and gimbal type head for wildlife, proper technique.

When you want to sell your images and compete with the guys who have spent a lot of money to get the best equipment you have to spend a lot of money and get the best equipment too, plus you most probably need to find something that differentiates your images.

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Thanks for the insight. Part of the issue might be my f/4 100-400mm lens, although it does have @ 3-stop IS. Its not fast, but not really slow either. The aperture doesn't give me much leeway to overexpose and drown out noise, however. I have a nice Gitzo tripod and ball head. A Canon 5DII would probably help a lot in the area of noise, but its beyond my budget for now. –  jrista Jul 26 '10 at 22:44
    
a bigger sensor would make a big difference for noise (if that's what you mean by "good camera") –  Jared Updike Jul 26 '10 at 23:37
    
I only have experience with one big sensor, but collective internet wisdom tells us there is a big difference between the full-frames also (trying not to go into the brandnames :). 5DII would certainly be a step forward, but it's still a resolution oriented camera. –  Karel Jul 27 '10 at 7:25
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I only apply some general noise reduction in Lightroom 3. Both in luminance and colour. The colour is the primary culprit.

That being said, I practically never shoot above ISO 1600 and to me ISO 1600 is often something I'm not really fussed about, at least with my 50D. In fact, I rarely skip a beat when having to dial up to ISO 1600. It's just part of nailing the shot with the right shutter speed and aperture in the given conditions.

With lower performance in the noise area however, I can see how you might be concerned. The problem really amounts to what feels right.

When you print an ISO 800 image, does the noise bother you? Do you apply any basic noise reduction?

This example, in particular is shot at ISO 1600. You and I can notice some noise but in no way does it really impact the photo at all.

enter image description here

Here is the 100% crop. Again, this is with some moderate noise reduction in LR3.

enter image description here

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