Slightly worried...

[Takahashi]

...that my camera's CMOS sensor might be moving towards the edge of the abyss.

I took this pic in near complete darkness purely as an experiment @ almost 10 minutes exposure, but discovered something potentially horrible. I've left the image at it's native res, to show the problem clearly : these random colour specks :

Is my sensor showing signs of it's age (approx. 6-ish years)? Are they some kind of "stuck" photo-cells, like the dead/jammed open pixels common on older TFT screens? Will this be a significant issue when I start some serious AP in the next few months?

Be gentle...

Ivor.

[Herakles]

Look like hot or dead pixels to me. If for astro photography use then darks/flats /bias frames should sort them ....as for ''normal' use ....hmmmm.

[Milamber]

For a CMOS sensor at 10 minutes that is a pretty good frame - do not make the mistake of comparing it to a CCD frame of the same exposure - CMOS sensors have *way* more noise than CCD sensors do.

Arthur

[Vega]

I agree, my 400D is much the same and these things only show their ugly heads with long exposures. Darks and bias will sort the dead pixels, flats will sort any dust bunnies or uneven illumination.

Matt

[jgs001]

Yep hotpixels... I've found a tool that's supposedly able to remove them, pixelfixer. I've not had an oppo to play as yet. I did find out that Camera RAW in Adobe (Photoshop and lightroom) will automatically remove hotpixels...

[Takahashi]

It's OK Arthur, I just wanted confirmation that I was over-reacting! ...and thanks for the info guys, it's good enough to know there's a way around the problem.

Cheers,

Ivor.

[brianb]

Yep hotpixels... I've found a tool that's supposedly able to remove them

Try configuring "long exposure noise reduction" in the camera. Does a dark frame subtraction for you, bye bye hot pixels.

[Milamber]

Oh - this is the Canon? That's pretty good then!

[Takahashi]

Yep, it is. I've had absolutely no problems with the camera, bar the urge to replace the two Pentax lenses with Canon/equivalents! I've already bought a 28-90mm AF zoom, snatched for a song on Ebay, and I'm on the lookout for a [whatever]-300mm zoom, or larger fixed tele. Fact is though, I've been churning out hundreds of frames of the Moon, Pleiades, Jupiter, etc unguided through the scope, although all but the Moon have been largely experimental, getting the feel of things, exposure times, etc. Great fun.