450D Auto Darks

[johnb]

Hi

My nice new 450D arrived this morning and I hope to try it out this weekend. My Sony had a long exposure noise reduction feature which I turned off and made my own darks. On the 450 I assume this feature is on and I just can't find how to turn it off. I assuming I should and if so how ?

Regards

John b

[Psychobilly]

Its in one of the custom functions...

Custom function 03 you might also want to haev a look at 04 (Hi ISO Noise Reduction) while your in there...

[jgs001]

I would, then you won't have to wait for each exposure to take twice as long. It's in the custom settings... third option, long exposure noise reduction... there are three settings... off, Auto (default), and on

[themos]

Canon EOS 450D / Digital Rebel XSi Review: 12. Menus: Digital Photography Review

Custom Functions II no.3

[lukebl]

Its in one of the custom functions...

Custom function 03 you might also want to haev a look at 04 (Hi ISO Noise Reduction) while your in there...

Sorry to butt in, but I also have the 450D and wondered about this. At the moment I don't use noise reduction at all, but take loads of RAW darks and flats before processing. In your experience, do you think it's worth doing the in-built noise reduction, or is the process of taking loads of darks and flats more effective?

[jgs001]

I guess in theory, the dark the ICNR takes is an exact match for the light, or at least as good as it's gonna get temp wise etc. But... if you're shooting 5 minute subs... in 1 hour you'll get 6 with ICNR, and you'll get 12 without. If you go on to produce an image with 76 subs in it.. that's gonna take a very long time without it... and you can, with care, get away with only using the one set of darks, around 15 of them, which can be shot at a seperate time to the lights, as long as you can get the temperature close (this is what I do). Get as many lights as you can when you can, and use downtime (cloudy skies) to grab some darks.

[lukebl]

I guess in theory, the dark the ICNR takes is an exact match for the light, or at least as good as it's gonna get temp wise etc. But... if you're shooting 5 minute subs... in 1 hour you'll get 6 with ICNR, and you'll get 12 without. If you go on to produce an image with 76 subs in it.. that's gonna take a very long time without it... and you can, with care, get away with only using the one set of darks, around 15 of them, which can be shot at a seperate time to the lights, as long as you can get the temperature close (this is what I do). Get as many lights as you can when you can, and use downtime (cloudy skies) to grab some darks.

Yes, that's more or less what I do. I forgot that using the in-built noise reduction doubles the exposure time. And, of course, that way you lose valuable imaging time.

[Psychobilly]

Nearly always better spending the time to get more Signal...

[themos]

Plus, not all darks are the same, that's why we stack them to a master dark, to reduce the dark noise. By subtracting each dark from each light, we introduce more noise into our calibrated frames.

[dph1nm]

Plus, not all darks are the same, that's why we stack them to a master dark, to reduce the dark noise. By subtracting each dark from each light, we introduce more noise into our calibrated frames.

It makes no difference whether you combine all your darks into one master dark or subtract each one individually from a different light. The maths works out the same. So

stacking 10 * (one light - one dark)

is the same as

stack of 10 * lights - stack of 10*darks

NigelM

[LukeSkywatcher]

I recently turned off this function because when i was trying to image Perseids i found that they only crossed my camera FOV while the camera was creating its own automatic darks.

[Sparrow]

IMO There is no doubt that the Canon's own noise reduction works really well (I have tried it out of curiosity). However, if you consider that between each 5 minute sub for example, you've got to wait a further 5 minutes while it takes its dark, then alot of valuable imaging time is lost - with clear skies a rarity in this country, I don't want to waste half the night while the camera takes individual darks so I prefer to take them manually at the end of the session. I'm also building up a library of darks for different exposures and different ambient temperatures so that if time runs out, I've still got some useable darks to process with.

[themos]

Nigel put me right!