Startrails for 5 hours above my house.

Quite pleased with this one. I've been trying for the best part of a week to find the right balance between ISO and shutter speeds to achieve nearly uninteruptable coverage for several hours without visible gaps in the trails; but at the same time being 'kindest' on the battery.

This is a composite of over 1400 shots at 10 sec exposures at ISO 100 so the K20D doesn't do it's mandatory noise reduction and can almost immediately get on with taking the next shot.

I used the Sigma 10-20 at 10mm f4.




The only thing I'd do something about is the branches towards the top right and just coming into view on the left. I'll have a bash at removing them in Photoshop at a later stage.

Very interesting. Have you rigged up an intervalometer?

I used a remote trigger (the button can be held down) and set the K20D to continous shooting.

Works good too

I should also say I used the fantastic free program called 'startrails' to composite all the shots. If interested you can find it here.

Wow,1400 shots Kind on batteries but not so on the shutter. What would a fully charged battery get you - an hour or two? On a very sturdy tripod you could change the battery OK and composite two or three shots. Alternatively I might invest in an AC adaptor (pricey yes, but worth it in the long term). I'm just waiting for the right conditions here (it's clear at the moment but too hazy for maximum star count) so I'll let you know what the results are on a full battery.

Good job you put a picture of what you are talking about, I was wondering what start rails were?

Well, there is a bit of a clue in the title...

I dont want to go down the route of a couple of uber-long exposures for a very good reason:

The image sensor get's much warmer on very long exposures and a great deal of noise creeps in. The camera would then be taking an equal amount of time as the exposure applying it's own noise reduction, therefore an almost uninterrupted coverage is just not possible this way.

The only way around that is to have just one exposure. One very noisy exposure. Trust me, I tried this a while back - it was'nt pretty.

In my honest opinion my approach is the best for the K20D, but yes, as you say it's not terribly friendly on the shutter. For me it was very much worth it. I'd rather get the shot I want even if it impacts the life expectancy of the camera by a week or so.

When I'm in a more remote location with less light pollution and more stars; this will be the technique I use.

Gosh that's very impressive and an interesting technique. Thanks for posting how to do it.

Regards

My pleasure Mat!

I forgot about the dark frame thingy. Amazing effort. Come to think of it I did try once with the K20 and it came out as you said. The K5 seems quite succesful, but it's still difficult (well. for me). I once did it with a little compact film camera and the results were excellent.

This is really cool Bob, excellent idea using continuous shooting rather than an intervalometer. Fortunately the K7 does 30 seconds without DFS, so if I had a go at this, I could do it in a third as many shots (and presumably use a smaller aperture). Did the exposure have to be correct on each shot for the program to work, or does it 'add' exposures together?

Really great result there Bob and my hat goes off to those that try this with a DSLR.

The only problem I have with taking long star trail images using a DSLR is the thought of that wear & tear on the camera electronics and all that post processing just to produce star trails still done better & more simply with film.

DSLR's certainly do a fine job on such shots so long as the sky background is not completely dark such as at dusk. However from dark sky sites where the sky background is much darker because each exposure is quite short to avoid sensor noise the sky background doesn't record so well and as a result the latitude between the bright stars and background causes harsh contrasty startrails with very dark backgrounds not aesthetically pleasing.

A single film image on the other hand not only records the star trails of any length you require depending on the ASA & chosen aperture but also the background glow of the milkyway.

DSLR's can record the milkyway very well ...and not too bad for star trails (with a lot of work) but to capture both milkyway & star trails in camera while being aesthetically pleasing is near impossible.

Mike

Cheers guys.

The culminative effect of the shots being merged does mean you can get away with a tad shorter exposures than you would normally take with a single shot BUT if there are no visible stars in any of the shots, it will not work I don't think.

Interesting info on the K-5 too - that's a step in the right direction! (Another reason for me to buy one....)

I'll post some K5 star trail and night sky images if you wish. I'm far from getting anything good yet as I'm still experimenting, but I think it would be capable of decent results in the right hands.