Shooting star trails?

[ronno13]

I would love to take some star trails and would like so feedback as to what turns out best.
I would have thought a 4 hour exposure at f22 is how it is done, but I have heard about taking multiple exposures and blend them together.These two attempts of mine (and I am not worried about the flare from a local street light at this point) were both taken with 2 minute exposures, the first being at f22 and the second at f3.5, both had a 30 second interval.
The first image had 4 exposures and the second one had two exposures.
Any other suggestions?

The first image

[ronno13]

The second image

[Donald]

Ron

On the question of aperture, you still have to consider issues of depth-of-field. If you are going to incorporate some fore-to-middle ground feature, then the aperture needs to be appropriate to have that in focus as well as the stars. If you're just going for the stars, then the DoF question come into play.

I've never tried a star trails, so there are others on here much better qualified to advise. But I did read recently of people stacking 200-300 30-second exposures to make a single image.

[enaiman]

I am no expert either but I did a bit of reading about.
I think stacking is the way to go most of the time, especially when there is some other light involved other than the night sky. Chances are high to blow something if a very long exposure is involved.
In my opinion, there is much experimentation involved to get the first exposure correctly, after that, just repeat it a number of times without much waiting time between consecutive shots or the stacked trails will be discontinued.

Most star trails pics I've seen include some other element than the sky, just to offer a more interesting composition. I think a tree outline would help but you have to move away from any street lights.

The aperture value will depend entirely on how long do you want the exposure to be; f22 seem a bit of overkill to me because it's very small for a night photo. There is also another consideration: if you are doing something wrong, you will see the result in 4 hours and if there is an error saving the image to the card ( happened to me a couple times for the camera to remain stuck at saving the image) then you may lose that image. That's why I say to use stacking - if an image is wrong or missing, you will see only a small gap in the trail.

Another recommendation, try to use the smallest ISO available to reduce noise (shorter exposures = less noise too, another argument for stacking).

What can I say? Good luck and happy experimenting

[Carl in Louisiana]

Try this out. Hope it works for you.

http://digital-photography-school.co...g-stars-trails

[ronno13]

Thanks guys, it'll give me something to work with.