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Nikonian

Nikonian

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Name
David
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hi all,

i had a play with startrails last night for the first time and this was my end result. any idea why the star trails are so choppy? i had the shutter release locked down for roughly ah hour and a half of 30sec shots, iso 800, f3.3. is it maybe because of the clouds rolling in? i tried creating a timelapse with startrials but didnt work out. "error". i did manage to create a timelapse with windows movie maker that turned out ok, i just dont know how to get it onto the forum. thanks for looking...

startrails_de_by_dlk0122.jpg
 
Firstly, may I say that the pic is good.
You say that you shot a series of 30 sec exposures. If I follow you then then the shutter was opening and closing every 30 secs (and mirror moving too unless it was locked up).
I get the impression that the trails are quite broad.
I can only think there was a vibration issue of sorts and perhaps a focussing one that has made the trails broad.
Never tried such a shot so I don't have first hand experience.
 
hm, had the camera on a tripod so i dunno if it was camera shake :bang:
 
Should be ok on camera shake with a decent enough tripod. I didn't have any issues with mine the other night. The broadness is proabably down to those being the brighter stars and some blooming has occurred. The choppiness is going to be the clouds passing through the image, it's in different parts of the image and almost random, so not going to be anything else.

Looks good though.
 
i really have to try this on the next clear night we get, these things look ace! im still confused on getting the correct star so you get the circular spin though?
 
Startrails allows you so save the sequence as a movie.
If you watch the movie it ought to be easy to see whether the stars are twinkling due to cloud or whether it's something else.

My 2p
If you look at the right edges of most of the trails there seems to be some gaps in common.
It's a bit like not all of the images got to be processed by Startrails.
If I'm right them the movie will appear to jump where there are gaps in the image set.
 
Also...... Whatever you do you will get small gaps in the trails....
Say your camera takes 1 second between shots - then there will be a 1 second hole in the trail every 30 seconds.
My 5DII is much quicker shot-to-shot but the gaps are still visible when the final image is viewed 100%.

One quick fix is to take the merged startrails and apply a small amount of radial blur centered on the middle of the start circles.
Works a treat but I don't think this is your problem here as the gaps are not even, but it may help recover a cracking image!

If you want inspiration have a look a Liquid in Plastic
Here's a technique article by the same author.
 
no i shot this with a tokina 11-16 2.8

i almost thought the same thing in regards to the one second it takes between shots but thought no way, one measly second over 30? i guess so! im gonna have a go right away and see if i can take the same shots and create a timelapse with startrails.
 
oskanoears said:
i really have to try this on the next clear night we get, these things look ace! im still confused on getting the correct star so you get the circular spin though?
Click to expand...

you're going to want to find the north star (polaris). what i do is find the big dipper. once located, draw a straight line and connect the 2 stars on the far end of the ladel. continue that line straight up and you will a somewhat brighter star, thats your baby. (y)
 
You won't notice star movement over 1 second at that sort of focal length. Even 30 seconds at 18mm barely shows it. It's only visible when pixel peeping. Stacking software like DSS is sensitive to tight star shapes otherwise it won't stack the subs, yet at 18mm there is no issue with stacking 30 second subs.
 
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