What am I seeing - noise?

[cmarbach]

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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?

 

Taken with my M8, 35mm summicron f2.0.

[Jamie Roberts]

Interesting. What was the exposure level? Is this a JPEG or RAW develop? If it's RAW, what converter did you use?

 

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.

 

The M8 has pretty sophisticated long exposure noise algorithms; I've never seen this in an M8 shot.

 

Now, all digicams have these pixels, and usually the processing (RAW or in-camera) takes care of them.

[brucek]

Out of curiosity was it a clear or overcast day?

 

Bruce

[jrc]

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.

 

JC

[cmarbach]

Here is the whole photo. Shot at f 8.0 at 1000th/sec.

[gdeliz]

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?

 

Taken with my M8, 35mm summicron f2.0.

 

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.

 

George Deliz

[cmarbach]

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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.

[Jamie Roberts]

I think John wins the prize here!

 

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.

[Riley]

sooo

its the jpeg that comes with the RAW

meant to catalog the frames ?

because they are always crap

[stunsworth]

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.

[Jamie Roberts]

@ 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.

 

@ 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.