Noise

I've just started experiementing with long exposures (i.e. 10 mins).

I've come across some noise which seems very strange.




This occured on a night shot on an 8 min exposure, I thought maybe the light pollution turned it red. But when I tried the same shot for 8 mins with the lens cap on, that was also red. Does anyone know what's happening and how I can avoid it?

I'm wondering if it's because my camera is low range (k110d)?

Thanks for any help.

Is this a case of the sensor heating up and creating its own 'noise'?

Perhaps other members with a greater degree of knowledge than me could explain further...

That's what I though. But I thought this was a bit excessive and wondered on any tips to decrease it?

Anyone?

Is this a crop ? And what was the iso setting used with this picture.
The K110D has a 6MP sensor,I believe? I ask because supposedly the lower mega pixel count cameras often handle noise better as the 10+ MP ones.

PhotoMe doesn't show any data, so sorry for so much questions.

Martin.

Sorry.

Yeah this is a k110d, 6mp.

f11, iso 200, exposure for 8 minutes.

This is indeed a crop at 100%.

It's taken with the noise reduction turned off. I was intending to use the lens cap exclusion technique, but it didn't work out too well!

I would like to see the full picture, instead of the crop.
It is a bit hard, this way in coming up with a answer that makes sense.

In comparison (hopefully) the next picture was taken with a K10D,ISO 100, about 18 minutes at F 5.6 and with NR ON. which took an extra 18 minutes.
I just show it, because now.......based on your posted example I would be inclined to think: "sensor problem". And of course I'll rather be wrong, in this case, and for your sake..

Martin.

Could the metering have gone all to c*ck because light has entered via the viewfinder?

That can affect metering, but once the mirror is up there should be no light-path to the sensor from the viewfinder.

G

This is the full Image




It isn't half as bad with NR on, but it just takes so much longer and wears down the battery.

The image is also mostly red and that's very strange

Does it always do that or only occasionally?

If this was a pitch black sky I (it was right, with those white lines being star trails??), I think you either have a sensor problem, or the camera simply doesn't handle night exposures very well.

Martin.

What was the white balance setting?

The white balance was daylight. The red goes if I use incandescent.

That's what confused me, the fact it was so red! Yes, it was pitch black and just pointed at the sky.

This one I did last night, but I tried a different technique. I stacked 24 30 second exposures and the noise isn't half as bad, also used the lens cap techniques to cancel out some of the noise.




Very strange.

The Earth moves quite quickly, so we are probably looking at star trails. Try similar exposures on the moon and see how far it moves as a comparison. That should clinch it.

Also don't forget the possibility of meteor and meteorite trails.

Sorry, John. Maybe I'm not clear!

I wanted star trails! That was why I was doing the long exposure. The issue was the massive amount of red noise!