Tips on using HDR at night?

Seems i'm asking too many questions today. Anyway, ill be photographing a skyline/light trails on highway and want to try HDR too. It's my absolute first with it, I use a modest Nikon d5100 and have the kit lens with me plus a 28-100 5.6 nikkor lens. What should my exposure bracketing be? And anything on the aperture you can shed light on?

1) DON'T do HDR at night…
2) HDR is taking 3+ images of differing exposure and combining…

Forlorn Hope doesn't know what he is talking about…

HDR photos at night are amazing if done right:

http://abduzeedo.com/outstanding-hdr-night-picures

You will need a tripod to do this. Your exposure bracketing will depend on what you are shooting. You will want one exposed for the sky, one for bright textures and one for dark textures.

You can only bracket 3 shots with a D5100, but 3 shots 2 stops apart is what I use for most of my HDR pictures. I only use more for extreme dynamic range shots such as a dim room with bright sunshine through the window then 5 frames 2 stops apart is a definite advantage.

Use aperture priority as you don't want aperture changing between shots was that will alter depth of field. Set your aperture to the DOF you want f5.6 or f8, as you normally would, obviously the camera will compensate by using a slower shutter speed with the low light available, so a tripod and cable release is necessary.

Colour balance will be a problem with different kinds of lighting, Sodium, Tungsten Halogen, Mercury Vapour etc. I always carry (and use) a grey card and take just one frame with the grey card in shot which makes getting colour right easy in post processing.

You may have a problem with noise, the best method I have found to minimise it is to use the Noise Reduction in Photoshop's Camera Raw on all frames then save as 16bit Tiff files and put those through the HDR software. This is the best method I've found for reducing noise without loosing too much detail.

I do quite a bit of HDR photography here's my HDR set on Flickr

Shoot in Raw as you need all the data you can hold onto. I use Photomatix Pro as my preferred software, but Oloneo is quite good too.

http://www.hdrsoft.com/

http://www.oloneo.com/

Try putting just the under-exposed shot through either of them it may give you all you want.

Night shots usually look best when there's still some light in the sky (Crepuscular Light) usually a beautiful Indigo 20 minutes either side of Sundown.

You're wasting your time if you try to shoot light trails in HDR.

It's simply not possible to get 3 identical images of different exposure. The light trails will be different in each image, and you'll end up with severe ghosting, AT BEST.

As it's night I would do a massive bracket, I would do 9 exposures with 1 stop between them the number 5 of course being the correct exposure, then experiment.using different ones maybe all nine.