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Terrible Noise/Pixelation With D300 - Active-D Lighting


whoz_the_man_huh

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<p>So, now that I'm home and have opened your image in CNX2 (rather than within Firefox on the crappy Dell LCD at work) I can see what you are speaking of. </p>

<p>If I take that image and apply noise reduction at 7, 5, Better quality, opacity: Luminance & Chrominance @ 30, 100 the noise basically goes away. </p>

<p>I would suggest that ADL at high is not that bad of a problem, since you are still having some rather bad clipping, and it would be somewhat worse if you hadn't used it. I wouldn't have used it, but would have adjusted the exposure to just barely not clip using the histograms on the LCD. In order to recover the image to my own personal tastes with a minimum of effort, try Auto Levels, advanced set to something between 20 - 40 for contrast adjustment and 0 - 25 for the color cast adjustment. </p>

<p>Finally, I'd selectively sharpen the final image with some USM and the Selection Control Point to only sharpen the areas I want sharpened (or conversely, to deselect the areas I didn't want sharpened. I usually have an upper limit for those of 20, 5, and not less than 5 for the threshold.</p>

<p>Cheers.</p>

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<p>I see the same problem (apparently randomly) on my D200 raw images, and it's not the same thing that Lex's cat shows. Usually it occurs when I've been taking a lot of shots in a fairly short time and when the scene has too much dynamic range or I've been switching ISO back and forth (it happens at ISO 100). It may be a banding problem (which some D200 are supposed to have due to a sensor problem) or something else. Either way, I didn't think it would also show up on a D300. I never see this for well/over exposed regions (I usually expose-to-the-right).</p>
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<p>Hi all,<br /><br />Thanks for sharing your vast knowledge.<br /><br />I went back to the park after work and it looks like Matt hit the bullseye. Disabling ADL removed all noise and artifacts:<br /><br /><br /><a href="http://www3.telus.net/public/svalmont/_3001241.jpg">Full res photo</a><br /><br /><br />Hopefully this helps another beginner in the future.<br /><br />Calvin<br /><br /><br />P.S.: This was extremely timely assistance as I am going on vacation this Saturday. Thanks so much again!</p>
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<p>Great news, Calvin. For what it's worth: if you have time, try settling ADL down to "normal," too, to see the difference between that and "high," since there definitely <em>is</em> a difference. <br /><br />I've been slowly dragging ADL into my thought process while out shooting the sort of stuff I shoot, and when it's not trying too hard, it can be a huge asset. For example, I sometimes shoot scenes on poorly lit gray days where I have to crank up the ISO to get good enough shutter speed to freeze action. When there are contrasty elements in the scene, ADL seems to err on the side of ever so slightly under exposing - and teasing up shadow detail in post will always bring up a little chroma noise. But I'm preseving highlight details that I otherwise would have lost, and these things are always a balancing act.</p>
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<p>Actually this is a overexposed capture, may be at the shooting time or RAw conversion time, but it is. So that the highlights have blown out. I think this is not the correct exposure for this kind of scene, in your full resolution posted image, I can clearly see that you tried to get more details in shadowed areas, so it happened but it is not as much of noise according to the lighting.</p>

<p>I just applyid the Auto Color and after that Auto Levels in PS, and now I don't find that "noise" which you say unacceptable...</p><div>00SnLv-117375584.thumb.jpg.53b7f2665fb91f77d24f1b1cca533ff7.jpg</div>

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<p>Am I being insensitive if I point out that, in my opinion, the OP noticed the so-called problem because there is nothing else to notice in that picture?</p>

<p>That maybe, just maybe, in a picture with a captivating subject, none of this would matter?</p>

 

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<p>It just comes down to what we individually consider great. The kind of pixelation and noise shown in the original photo I posted precludes greatness in my opinion.</p>

<p>Having the second photo, I'd toss the first without a thought whereas you wouldn't find anything displeasing about it.</p>

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<p>Oh come on! Just print the damn picture and see if you still notice anything. I bet you don't have a big enough printer to have a chance to notice it on print. At some stage you even told someone to zoom in at 200% to see it. How meaningful is that? Display it as big as you screen allows to see it completely and reflect on that "terrible pixelation" (your words).</p>

 

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<p>Stephane's point, Calvin, is that pixel peeping will make you crazy, and for no reason. When you zoom to 100% on your typical display, that's like looking at a print that's several feet across. By the time you render those prints at a normal-ish size (say, a 12x18 - which is a pretty big print), you simply won't be able to see that stuff. Getting distracted by it can lead you away from worrying about the larger composition, narration, and technique issues that actually make or break an image in real life, practical terms. <br /><br />Also, just to help future communication: noise is a very, very different thing than "pixelation."<br /><br />Think of pixelation as situation when an image that has higher resolution and should be showing more subtle changes between two or more adjacent pixels instead shows them lumped together into adjacent pixels that share the same value. Your image has the same number of pixels not matter how much the detail is wrecked by compression artifacts. But it's compression artifacts that cause a handful of subtly different adjacent pixels to all wind up showing the same color/tone, and thus looking like one, larger, chunkier pixel. Hence pixelation. Of course, this can also happen when you take a low-resolution image and up-size it to include more pixels - but that's not what's at hand, here.<br /><br />The only thing on the table in this case is noise. And the only thing that really mattered was chroma noise. Depending on the software you're using, you'd be amazed at how well that can be brought under control. But before you do <em>anything</em> more to an image, spend the $1.00 a few times to actually produce prints. It will completely alter your thinking on the subject.</p>
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<p>Matt, thanks for educating me. You rock.</p>

<p>I do large prints. One of the reasons I upgraded from the D40 was to get good quality beyond the size of my last print at 16 x 20. That is, I will go to 20 x 30 once I have a shot I really like. Why? The reason is I'm no expert, but rather just a guy who likes big prints of his wife. And of course the photos I develop of my wife and I together are not even taken by me.</p>

<p>As you suggested, I'm trying my best to develop my poor technique. Your fixing the noise issue for me once and for all has no downside, as far as I can see. Thanks a million again.</p>

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<p>The key to the whole thing (since, at 20x30, you're definitely at your camera's boundaries) is proper exposure. You definitely want to keep the ol' "expose to the right" (look it up!) in mind, so that the details in the darker tones to have to suffer the noisy degradation of being pumped up after the fact. The histogram display can be very helpful, in the field. But more than that, it's a matter of learning when and how to use which metering technique. That's the big one. Your camera definitely can't read your mind, and despite Nikon's brilliant engineering, it can't know what's most important to you in a given scene. It will seem contrary to most newer users' thoughts, but the sooner you get <em>away</em> from having the camera's metering system do all the work, the better.<br /><br />Don't get me wrong - I'm an Aperture Priority kinda guy. I let the camera figure it out all the time. But I help it out by deciding when to use spot, vs. matrix metering... or when to compensate by a stop or so when I know that a bright sky is going to torture my results. That just takes lots and lots of shooting. The good news is that with a D300, you have an incredible tool to work with, and nowhere to go but up in terms of results. Before you know it, all of this stuff will take a distant mental back seat to what really matters: looking through the view finder, and asking yourself, "Why am I about to make this photograph? What can I do with my composition, or with where I'm standing, or with with direction the light is shingin, to make it ten times better?"</p>
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<p>Well, that might sound like a good idea at first, Calvin, but I suspect that the world gets enough of my ramblings and mutterings already. Now, I'm going to put down the keyboard, and pick up the camera, and practice a bit of what I'm preaching. Note to self: take no silly pictures for the next 24 hours. Only Important Photographs. Oh, look! A dog! I'm hopeless.</p>
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<p>Calvin, you might be very interested in this discussion by Emil Martinec (physics prof from U of Chicago, who is an expert in digital imaging and string theory). As he explains, shadow noise is going to be greater at ISO 100 or 200 and near optimal at ISO 1600. This is a real surprise to just about everybody! He proposes a bi-amplified analog front end that processes low level signals at ISO 1600 and highlights at ISO 200 and demonstrates the results with his "teddy bear and lamp" test. This is clearly the kind of finding that would benefit the images you are trying to capture. You can shoot two exposures of the same scene at these different ISO levesl and blend them. But either way, you can see how the expectations of getting clean shadow detail at low ISOs is just a myth.<br>

<a href="http://forums.dpreview.com/forums/read.asp?forum=1018&message=28749589">Sensor DR vs Camera DR: Open Talk Forum: Digital Photography Review</a></p>

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