Originally Posted by Roger
Which brings me to a question.
I assume a lot of these are composite shots comprising of several relatively short exposure photos blended together, but I know some on here take quite long exposure photos using digital cameras.
How do you do this? Cos every time I try to do a long exposure, no matter what the ISO setting I end up with a photo full of hot pixels.
Roger, the trick to doing star trails with a DSLR is stacking a load of shorter exposures with a "Lighten" blend method, eg in Photoshop or Startrails v1.1, a nifty bit of freeware.
Set your camera to burst mode, ISO to about 400, exposure to the longest your camera will do (eg 30 seconds), fire the shutter release and lock it
. Go away and do something else for an hour or two, then when you return, assuming your battery hasn't run out, you will have hundreds of shots to stack. You can take a torch or flashgun to illuminate the foreground.
As for untrailed shots, then you either need a high ISO and dark sky or some sort of tracking platform, like an equatorial mount or Astrotrac. A tracked image will make the foreground appear motion blurred, but you can cut and paste the foreground from another shot, or use the "lighten" blending mode trick.