Night and star shots.. focusing & other how-to tips please!

[FrankieP]

Hi all,

Would love to hear any advice and tips for a newbie on shooting astronomy and / or night landscape shots. I'm super new to all this and since I only have a D40 with the kit 18-55mm lens I'd be happy to just get a clear shot at this stage, haha.. I don't have a remote yet to use the bulb function to hold the shutter open for a long amount of time so have just been using the shutter-priority set to the longest, 30", and with the focusing if I can get a clear shot.

Have been having problems focusing though to get clear pin pricks of light from the stars. It's not auto-focusing but when I try manually focusing I can't tell really how clear it is, and even when reviewing and making minor adjustments after each shot it's hard to tell. I thought I'd had the focus set manually to infinity, but even then it's not really sharp. Should I expect to get sharp dots with what I have? Or do I really need to wait until I have the remote and so can get the shutter staying open long enough for a much brighter shot to tell whether I'm focusing clearly or not? I've tried using a higher ISO but the graininess didn't really help.

Shooting landscapes at night is something I'd like to experiment with too, and whilst I've had much better results with that the focusing is still an issue.

[aim54x]

Firstly, there is no reason for you to be unable to produce good images with your current gear.

For night work, a stable surface (or a tripod) is a must.
Use the self timer (unless you own one of those ML-L3 IR remotes for the D40)
I would keep the ISO as low as possible and keep the shutter open for 30sec - you should be able to get a decent aperture doing this.
Manual focus if you must - just remember that more than likely you can just go to infinite focus if you have nothing in the foreground, otherwise a good torch is helpful in focusing (ie shoot in manual, set your exposure and then switch on the torch to illuminate the foreground object that you want to focus on, hold the focus lock, turn off the torch then fire the camera - i have done this many times)

HOWEVER these longer exposures may lead to tiny star trails, if you want pin pricks you want to keep your exposure short, so bump up your ISO and open up that aperture.

If you want star trails (a project that I will undertake as soon as i find some time) some guys on the forum (BigV and AdamE) were taking lots of short exposures and stacking them using photoshop. I'd give that a go.

Good luck

[Mr Darcy]

Hi Frankie,
Cameraon has said most that I would.
BigV seems to be the expert here.
I will add a couple of things:
Ignoring the Copernican revolution, stars move. the longer you hold the shutter open, the further they travel and the blurrier your shot will become. There are only three ways around this that I know:
1. Move the camera in synch with the star movement. The professionals do this, but the gear to do it well comes expensive. There are some cheap options that do a reasonable job, but they take practice. There was one covered in a post a few weeks back. Bookleaf mount or thereabouts. Search for it.
2. Use a fast shutter. That means high ISO and wide open aperture
3. Accept the motion and go for star trails.

The other thing to be aware of is that if you take your camera outside at night, you can get condensation on your lens because of the temperature differential. The fogging can be slight but leads to blurry pictures. Make sure you take it outside early enough for things to settle down, and maybe clean the lens before you expose.

Also do some tests. You may find your lens actually focuses beyond infinity. Check the exact setting to get a good focus of an extremely distant object during the day. Then use that setting for your star exposures.

Oh and your camera needs to be rock steady. Don't set it up on the back verandah. Find some bare earth some distance from the house and any road or even foot traffic.

Choose a cool, clear, calm night well after sunset to avoid atmospheric disturbances.