How to take star photos/making a time lapse with a Nikon D40X

[camphor53]

I'm not a photographer, but I've always thought astrophotography was cool. High quality photos showing an awesome amount of stars are great. Time lapses too. I've borrowed a Nikon D40X and have decided to try it out for myself. The lens is 18-55mm and the possible ISO settings are 100, 200, 400, 800, 1600 and H1/3200. The exposure time can go from 1/4000th of a second to 30 seconds, then goes to BULB.

Basically I just set the camera up on a tripod and started taking photos with the remote. I didn't really know what settings I was messing with, except it was on "Auto (no flash)" which got rid of the "subject is too dark" message, and the photos seemed best when the ISO was on 800. When I hit the remote it took 25 seconds to shoot. Does this mean that it took 25 seconds to collect enough light? After it shot I waited ten seconds and pressed it again. I did this for 43 photos.

Here's the first photo I took of the 43. It's converted to JPG from NEF (Nikon's RAW format). The resolution is 3900 x 2613. (Crux is visible over to the right)
http://img695.imageshack.us/img695/8385/dsc00871ox.jpg

Are the stars so blurry in this photo because it was very windy? I know that we see stars as "twinkling" because the powerful winds in the atmosphere shakes their light around.

Then I put each photo in a small timelapse video. There's 100 milliseconds between each frame.
http://www.youtube.com/watch?v=e0GiReEnfHk

The location I took these in is a city so there's lots of light pollution, but I'm going up to a very dark rural place soon and that's why I really want to learn how to do this properly.

Using the camera today I now know how to set it to Manual, and set the aperture and exposure length. I want to take more photos tonight though, so are there any specific camera settings I should be using? Does anyone have any tips for a beginner? I get that less light means more exposure but there's still more to it.

By the way, with time lapses, when people get shooting stars in their time lapses, how quickly are they taking their photos?
Like in this one: http://www.youtube.com/watch?v=0kPw3rNSQrE

Plus what program is generally used to put all the photos together? I use AVS Video Editor but each photo is set to display for 5 seconds by default. I had to go through and change the duration to 100 milliseconds on each 43 photos. It took a long time.

Thanks.

[CarlJoseph]

Nice little movie you made there. :thumbsup: I haven't made any myself so can't comment much on that side of things.


In auto-mode, yes. The camera probably needed 25 seconds for enough light to register on the sensor. These cameras though aren't well tuned for astrophotography in auto-mode so going manual as you mentioned is your best option.


The twinkling is because of atmospheric conditions, including wind. I would guess that your stars are a little blurry because the focus is a little off.

I used to use a Nikon D40 (not the 'x' though) and found that focusing was the most difficult part of all. The infinity mark on many lenses is not accurate so don't rely on it. Here's what I'd do...

Get focused first

Put everything on manual, including focus
Make the aperture wide open (smaller f number)
Set the exposure for around 30 seconds
Set the ISO for around 1600
Take a single shot of a bright star (sirius is a good one)
Preview the result and zoom in on the viewfinder to check the focus
Adjust the focus very very slightly and try again
Keep going until you get a nice sharp focused image of that star


Tuning for your shot
Now, once you've got it focused nicely, point it to the area you want to shoot without moving the focuser on the lens.

Try a few practice shots playing with the ISO level and exposure time.

The higher the ISO the more sensitive the sensor will be to light coming in. This means you can use shorter exposures. BUT the higher the ISO the more "noisy" the final image will be. It's about finding a nice balance.

The longer the exposure the more star trails you will get (as the stars move through the sky). Going much longer than 30 seconds will require tracking or a fancy mount or something like that so try to stick to around 30secs.

Go for it
Now you're ready to do your multiple shots. :D Looking at your video, your previous timings seemed to work well so keep at it.

Cheers,
Carl