Somrthings not quite right

[keef_uk]

Hello,

Recently I have noticed that images are suffering worse from (forgive me I dont know the correct term!) redness and noise. I took a selection of shots from ISO1600 (1 at 400) with differing mettering modes. All 25 seconds. All taken whilst attached to 102SLT

Its only happening on long exposures so its the chip getting hot? It seems to be getting worse cause I didnt suffer this badley before.

Is there anything I can do to improve it?

Cheers

[brianb]

Worsening light pollution ... maybe due to damper air, the Atlantic stuff we have at the moment is much damper than the dry very cold air we had in December.

[dph1nm]

What do you mean by different metering modes? You should have the camera set in manual and keep everything fixed between shots (including manual white-balance).

NigelM

p.s. you seem to have a lot of vignetting - I use a 2" camera adapter on my 102SLT, which seems to help.

[keef_uk]

@dph1nm these were just test shots so used different modes for diag purposes

[Zakalwe]

This is a dumb question, but are you covering up the viewfinder to prevent light leaking into the camera body (assuming you are using the 400d)?

[keef_uk]

no Zalalwe im not - should I be?

[Zakalwe]

no Zalalwe im not - should I be?

Yes. Light can enter the viewfinder and get reflected onto the sensor by the viewfinder prism. Canon normally supply a little rubber doobrie (technical term) that slides onto the camera strap that allows you to block the viewfinder. I normally just stick a bit of tape over the v/f.

The shape of the light is not even on your exposures.....that's what makes me think that light is "leaking" into to camera.