Need help with Star trail shots

[cali]

I would like to try my hand at it but I was wondering if you could give me some pointers and advice. I know it requires very long exposures usually up to an hour but is there anything else to know? I live in Los Angeles and am thinking about driving past Mojave one night and try it out. Any advice?

[Billginthekeys]

for one thing, in order to get an exposure that long, you will need the timer remote to set the shutter for that long. and you will need a strong neutral density filter.

[Jaime]

Aim for the North Star and you will wind up with a circular trail.

[Curtis N]

you will need a strong neutral density filter.I'm not sure what good one of those will do for star trails. I've taken a few myself and seen several others posted here. I've never heard mention of an ND filter for this purpose before.

One of the hard parts is getting a good infinity focus. If there's a moon, focus on that, then switch to MF and don't mess with the lens.

I have had good results at f/8 but you can experiment with different apertures. It's not practical to use the long exposure noise reduction in the camera - it requires as much time as the exposure and may require more battery power than you have left after the shot.

Try to get the north star in the frame, use ISO 100, have fun and expect some trial and error.

[Billginthekeys]

you can shoot for an hour at F8 and not blow the exposure. i have never tried star trails, since the timer remote has always been at the bottom of my wishlist and never quite made it into my hands. i just assumed that at almost any fstop the picture would get blown after an hour without an ND on there.

[Curtis N]

This thread (http://photography-on-the.net/forum/showthread.php?t=104167) has a shot I did a year ago with a 300D. Half an hour at f/8, and it's still pretty black where there were no stars. You need to be in a fairly remote location to avoid light polution.

[kfong]

The electromechanical shutter sucks battery juice like crazy. Best to use an external power supply.
Every hour the stars will leave trails of arcs of 15 degree.
You can also take shorter exposures and combine them later using Photoshops.
Make sure you have a rigid tripod and will not be moved by winds.
Watch out for critters that prowl the night. Don't know what 's in a desert, but the dark site close to my neighbourhood I'll have to be careful not to become bear food.
Park your car behind the camera. If you are using f/8 you can open and close the car door without ruining your picture.

Ken

[John_B]

cali,
In my opinion you don't need a ND filter, you don't need a timer remote. You do need a sturdy tripod, you do need a fresh charged battery or external power supply and having a remote switch is a benifit. Of course the darker the sky (and less clouds) the best :)

Here is a shot I took with my 10D for 1277 seconds
http://johnbdigital.com/favorites/shutter_1277.jpg
Click for Specs (http://johnbdigital.com/favorites/shutter_1277.htm)

Good luck with your shots :)

[Curtis N]

you don't need a timer remote.Yeah I missed that part of Billy's post. Any of the remote switches have a way to lock down the button and keep the shutter open as long as you want with the bulb setting.

[SimonG]

... It's not practical to use the long exposure noise reduction in the camera - it requires as much time as the exposure and may require more battery power than you have left after the shot. ...
This is a good point. I generally do dark-frame subtraction manually in post when I am shooting long exposures, as this allows me to shoot a single dark frame (one for each different exposure, if I am doing more than one), which really helps with battery life. I generally shoot the dark frame as I am taking down my tripod for the evening, and it works pretty much the same way as the in-camera noise reduction.

[Billginthekeys]

Yeah I missed that part of Billy's post. Any of the remote switches have a way to lock down the button and keep the shutter open as long as you want with the bulb setting.
thats good to know too :D. although id still rather get the timer remote myself. the time lapse features looks sweet too.