cmarbach Posted February 15, 2007 Share #1 Â Posted February 15, 2007 Advertisement (gone after registration) This winter scene, that you are seeing a part of, has interesting blue, red, purple and white dots in the water near the bottom. What is this? Â Taken with my M8, 35mm summicron f2.0. Link to post Share on other sites More sharing options...
Jamie Roberts Posted February 15, 2007 Share #2 Â Posted February 15, 2007 Interesting. What was the exposure level? Is this a JPEG or RAW develop? If it's RAW, what converter did you use? Â They look a little like long-exposure pixel errors, though I've only ever seen these "exposure-related stuck pixels" show up in red, but that's just my experience with the Canon 1ds2 and C1, actually. Â The M8 has pretty sophisticated long exposure noise algorithms; I've never seen this in an M8 shot. Â Now, all digicams have these pixels, and usually the processing (RAW or in-camera) takes care of them. Link to post Share on other sites More sharing options...
brucek Posted February 15, 2007 Share #3 Â Posted February 15, 2007 Out of curiosity was it a clear or overcast day? Â Bruce Link to post Share on other sites More sharing options...
jrc Posted February 15, 2007 Share #4 Â Posted February 15, 2007 I think it's refracted light coming through the water globules, very over-exposed because you're getting the direct shot of refracted light into the lens, against that dark background. It's similar to specular highlights. Â JC Link to post Share on other sites More sharing options...
cmarbach Posted February 15, 2007 Author Share #5 Â Posted February 15, 2007 Here is the whole photo. Shot at f 8.0 at 1000th/sec. Link to post Share on other sites More sharing options...
gdeliz Posted February 15, 2007 Share #6 Â Posted February 15, 2007 This winter scene, that you are seeing a part of, has interesting blue, red, purple and white dots in the water near the bottom. What is this? Â Taken with my M8, 35mm summicron f2.0. Â Looks like a common aliasing artifact ofter referred to as Christmas tree lights. Can also be an artifact of JPEG conversion or even just of a particular screen magnification of a JPEG that disappears at a different magnification. Â George Deliz Link to post Share on other sites More sharing options...
cmarbach Posted February 15, 2007 Author Share #7  Posted February 15, 2007 Advertisement (gone after registration) Interesting. What was the exposure level? Is this a JPEG or RAW develop? If it's RAW, what converter did you use? This is the Jpeg out of the Camera, I also have the RAW file. Link to post Share on other sites More sharing options...
Jamie Roberts Posted February 15, 2007 Share #8 Â Posted February 15, 2007 I think John wins the prize here! Â I'd also try a careful RAW conversion into a wider colourspace, since you typically have much more sophisticated noise control and highlight headroom, though in context it's pretty clear these are artifacts of exposure. Link to post Share on other sites More sharing options...
Riley Posted February 15, 2007 Share #9 Â Posted February 15, 2007 sooo its the jpeg that comes with the RAW meant to catalog the frames ? because they are always crap Link to post Share on other sites More sharing options...
stunsworth Posted February 15, 2007 Share #10 Â Posted February 15, 2007 I think it's IR being isolated from the spectrum because of diffraction caused by light passing though the rough surface of the water. Ive seen similar from the surface of a wet road even when shooting RAW. I've been assuming that the IR filters will cure it. I'll post an eample later this evening. Link to post Share on other sites More sharing options...
Jamie Roberts Posted February 15, 2007 Share #11 Â Posted February 15, 2007 @ Riley--no, I think he was shooting RAW + JPEG mode. I'm not sure why the *posted* image is so bad; it looks like a GIF. Â @ Steve--I don't think this is an IR issue at all, since all other digital cameras do this too with point sources of light, regardless of their susceptibility to IR (the Canon dSLRs with fast glass are especially prone to this effect, and not just on overexposed water droplets, but on any high-contrast edge. IR filters won't cure it, but there are a number of ways to deal with it in post. Link to post Share on other sites More sharing options...
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