UKH

I've not done any yet, however I am planning to. From the little that I know, there seems to be two techniques, of stacking and long exposures.

Could somebody please explain the merits of both and when each would be most successful to achieve good star trails with a foreground subject?

In reply to The Lemming:

I've done both, and find I have much more control via stacking, but that sinking feeling that you're not doing it all inside the camera and are therefore cheating in some way. What I mean by more control, is that if you take a bunch of 30 second exposures and merge them in photoshop, any light pollution has been reduced massively, as you've only exposed for 30 secs instead of potentially hours. Also, it limits your susceptibility to a single catastrophic event that reduces your entire nights work to nill, like a passing mountain biker with a headlight so powerful you forget its night. Another good advert for stacking is that it’s much easier to clone out the flashing lights of passing aircraft for instance, as your image will be less busy for that 30 second exposure. I would also take one image specifically exposed for the foreground, cut it out in photoshop and stick it on the front of your stacked images. I suppose the main pro of the long exposure alternative, is that there’s less post processing.

In reply to Mark Collins:

What software could you use for stacking images?

In reply to The Lemming:

Photoshop. Load each image one by one to an individual layer and set that layer's blending option to lighten I think. There must be an easier way of doing this, you may be able to batch some or all of this, sorry I can't quite remember.

In reply to Mark Collins:

Thanks for that, I'll give it a go the next dark night.

You region 30 second bursts are a good starting point?

Sorry for the brevity of my reply as I'm out walking the pooch.

Cheers

In reply to The Lemming:

If you want to use some astro specific software you could try registax : http://www.astronomie.be/registax/

it has all sorts of filters etc built in.

Marc

In reply to The Lemming:

yes, I went for 30s with the widest aperture on my slr after reading something about it on the web. It took an hour in all, but would definitely look better with 2 maybe 3. I would say definitely worth taking a few test shots to start with to make sure things are exposed to your liking. I'll post my results on here when I get a mo and put a link on this thread.

In reply to The Lemming:

Shhhhh. Robert Durran might be listening.

In reply to Mark Collins:
I may give my Trigger Trap a dust-off as well. It was a tip from a fellow UKC member.

I've found it excellent for time-lapse so I'll give it a go with star trails too.

http://triggertrap.com/


Just found this tutorial that covers everything I need to start playing

http://player.vimeo.com/video/100712853

In reply to Mark Collins:

Congratulations Mark, nice image.

A few tips I put together on this site at: http://www.ukclimbing.com/articles/page.php?id=6741

In reply to Mark Collins:

Very well done sir.

May I ask how you captured that image, from setting the camera up to the finished product?

Cheers

In reply to James Rushforth:



Thanks for that. I'll have a play tonight, weather permitting.

Thank you everybody for your advice.

In reply to The Lemming:

I prefer the results from a single long exposure mostly, although it is harder to pull off. If there is any light pollution then you are probably better off stacking, as it tends to swamp long exposure images unless you are v careful.

In reply to James Rushforth:

Sadly a cloudy night so I can't go out to play. However I've been doing a bit of reading and something is confusing me and its about ISO settings.

From what I read single exposures then you dial down the ISO as low as possible and with stacking shots then you crank up the ISO to1,600 or there abouts.

Could somebody please explain why I'd crank up the ISO settings when stacking images at 30 second intervals?
I'd have thought that a lower ISO would cause less noise and still recording the star trails.

I'm confused.

In reply to The Lemming:




Thanks very much. I think I've covered most of what I did in my posts on here, but you can use James's article to fill in the bits I haven't, plus his more in depth knowledge. He's also right about it being a lonely business. I was fortunate that I could wander off for a walk up Rivington Pike and around the terraced gardens while my camera was running, with the notion that theft was unlikely what with the lack of people and the darkness. Let's see how you get on, and by all means post more questions and I'll try to answer.

In reply to The Lemming:


I've no idea why you'd do that except to establish your timings, which you already have (30 seconds). I used ISO 100 for the image I posted, F as low as it could go around 4.5 I think that is. High ISO is generally bad (grainy) in budget to medium SLR's but I have seen some extraordinary results with other people's high end kit.

In reply to James Rushforth:



Thanks James, great article.