star trails photography ???

[Darawan]

i shoted star trails A weeks Ago , but i saw these photo I need some inforamtion
http://static.squarespace.com/stati...031f96a657fb8/1380383179397/motor zoom 2b.jpg
how i can take photograph s like these ?

 

[snowbear114 45]

Please don't post photos that are not yours. Provide a link to them instead.

You need a tripod and a very long shutter speed. Though the spiral makes me think this is more Photoshop than usual.

 

[Darawan]

Please don't post photos that are not yours. Provide a link to them instead.

You need a tripod and a very long shutter speed. Though the spiral makes me think this is more Photoshop than usual.

i hear that they use slider ???????!!!!!!1

 

[Gavjenks]

Yeah the spiral effect is not natural, they did something weird in post processing (Or POSSIBLY some sort of weird trick with zooming during exposure or something, but I'm not 100% sure that would work, and if it does it requires expensive equipment). But otherwise, you do this by stacking a bunch of exposures as the sun sets. During sunset, the sky is more orange, and the later, the sky is more blue, and as long as stars are visible during both, you get a cool color combination. Also just some stars are red and others are blue to begin with, so you can get a similar effect by upping saturation and such, but it is magnified by sunset.

And then typically for the foreground, you just use one of your exposures only, without all the overlapping. Most likely you take a separate exposure just for the foreground the way you want it.



The technical details are easy to find on google, and are not worth typing out again here. Just look up basic tutorials on "star trails" or "astrophotography" for stuff like what exposure settings to use, or how to apply curves in photoshop to get stars to stand out from noise.

 

[jsecordphoto]

I've never seen startrails with that pattern, like others have said I'm guessing thats photoshoppery

 

[Gavjenks]

The more I think about it, the more I am convinced you could in fact get a spiral just like that by hooking your zoom up to a cine motor and gradually zooming out over the entire exposure period.
However, this would be an awful lot of effort, and exposure equality would be an issue (you'd need to heavily rectangularly anti-vignette to make the outer stars as bright, since they weren't in the frame at the start). Also, it would be impossible with the windmill in the frame. You would have to get a clear shot of the sky somewhere else (perhaps just 100 yards to the side), and then photoshop it in as the bacgkround behind the windmill, so it requires very significant photoshopping anyway, why not just do it all in photoshop?

 

[jsecordphoto]

I have seen photos where people zoom out slowly over a long exposure of the stars and it looks nothing like that. more like the scene in star wars where they go at warp speed

 

[Gavjenks]

Warp speed would be if you zoom out over the course of a 4 second exposure or something. If you zoom out over an hour exposure, you can't get straight lines. The zoom is straight, but the stars are spinning = spiral.
Here, I just went into my bedroom and confirmed it using a zoom lens and a laser pointer that I spun in a circle on the ceiling.
One is without zoom, the other is with. Same circular motion in both cases. Not the best quality test, but I think the results are still pretty obvious.


Notice the things that stay relatively still during the exposure -- the popcorn ceiling texture -- look like warp speed. But the thing that was noticeably spinning becomes a spiral. So if you zoom out in a fast enough exposure that you wouldn't normally see star trails, you'll get warp speed. if you do it over a period of time when you normally would get huge star trails = spiral. You can adjust how spiraly the spiral is by choosing in between shutter speeds.

 

[jsecordphoto]

The exposures I have seen were typical times for photos of the stars...25-30 seconds. Still not long enough to get trailing with the UWA lenses used. I see your point though

 

[Gavjenks]

Ah well yes, you'd have to zoom out over 30+ minutes, and probably more like hours (or several 30 minute exposures depending on look you want) if you want a seriously densely populated spiral.
More like the exposure times used in the image in the OP.

 

[Darawan]

i think they are using machine for zoom or DIY motorized slider . ?

 

[ceejtank]

My buddy does shoots like these. You take one where you shoot the stationary object (windmill) and then you take a lot of 30-40 second exposures of the stars, combine in photoshop afterwards.

 

[NancyMoranG]

Ceejtank, I am NO expert but I think the process you describe would give a different effect. 'Yours' would give the 'illusion' most of us see, the stars all staying in a perfect circle around the North Star. ( like a drop of water and rings appearing) This link, gives a look of 'water going down a drain' or such or do I dare say a vortex?
Curious photo.
Nancy