DSLR internal dark frames

[perfrej]

Hi all!

Tonight is a very rare occasion this winter: clear weather!

I'm actually going to stuff my car with the gear and drive to the least light-polluted area with an hour's driving range.

I'm thinking about the Canon EOS 1000D that I have. When I started out with it Nebulosity would report "subtracting internal dark frame" which in a sense seems sensible; one dark for each light, taken at the same time and with the same exposure time. I turned the feature off and started taking darks manually.

Has anyone compared the results? Should I dare to to automatic dark subtraction tonight? Is anyone even using the internal dark subtraction feature?

All the best for now!

/per

[GrantEb]

I'm not sure how it works with Nebulosity, but as far as I know, in dark frame subtract mode, it only owrks in JPG mode, and doesn't apply the dark subtract to the RAW output.

I suppose it depends on what you are imaging really, and how long you have. It takes double the amount of time to get a result.

I suppose you could always try it to compare to previous results.

[Photosbykev]

Personally I think you get a better result subtracting darks manually. It also means that you can double the number of lights you take during a session which is always good.

[jgs001]

I've not compared the results, but you'll use half your clear night if you use the internal camera dark reduction. Given how rare clear skies are, it's better to maximise your light captures, and take a bunch of darks at the end, or take a few at the beginning whilst setting up and a few at the end whilst clearing up.

[Psychobilly]

For me it would depend on how the camera "behaves" with changing sensor temperature..

Some of the older cameras have darks which change quite dramatically with temperature and durign the first few frames of exposure... When i was using my D200 i would satrt it running "early" for it to get up to a stable sensor tempertaure...

Taking More lights is nearly always the best thing to do...

Billy...

[perfrej]

yes, I will take lights the whole valuable time, that's true. I do beleive the 1000D will do subtraction on raw files as well as jpegs, mainly because I have seen it do it.

Anyway, I've been out here in the middle of nowhere now for six hours straight, so I'm going to pack up and drive home now.

I did get nine good 10-minute exposures of M51, six of sunflower and a set of darks to go with each. We'll se how it turns out. Trial of Pixinsight expires today so I need to fork up some dough for that. Add to that the fact that I happened to order a Megrez 90 yesterday

Nite-nite all...