Luminous Landscape Forum

Raw & Post Processing, Printing => Digital Image Processing => Topic started by: Redcrown on May 10, 2013, 12:27:10 pm

Title: Strange light trails on long exposure night shot?
Post by: Redcrown on May 10, 2013, 12:27:10 pm: I shot a bracketed set of a night scene and in the longest exposure I have some strange light "trails". I've never seen anything like this before and wonder if anyone can explain what caused them?

Here are two images from the bracketed set. The top image is a 5 second exposure and has the light trails. Bottom image is a 1.6 second exposure from the same set. It shows no light trails, nor do any other exposures less than 5 seconds.

http://kellyphoto.smugmug.com/photos/i-QDvBNwj/0/O/i-QDvBNwj.jpg
(http://kellyphoto.smugmug.com/photos/i-QDvBNwj/0/O/i-QDvBNwj.jpg)
Title: Re: Strange light trails on long exposure night shot?
Post by: Bart_van_der_Wolf on May 10, 2013, 12:37:25 pm: Quote from: Redcrown on May 10, 2013, 12:27:10 pm
I shot a bracketed set of a night scene and in the longest exposure I have some strange light "trails". I've never seen anything like this before and wonder if anyone can explain what caused them?

Hi,

Since those are camera movement induced, are you sure that the shutter had closed when you removed the camera from the tripod (if that's what you were using)?

Cheers,
Bart
Title: Re: Strange light trails on long exposure night shot?
Post by: Schewe on May 10, 2013, 06:50:10 pm: You kicked the tripod doode!
Title: Re: Strange light trails on long exposure night shot?
Post by: Peter McLennan on May 10, 2013, 07:30:39 pm: Absolutely.
Title: Re: Strange light trails on long exposure night shot?
Post by: Gulag on May 10, 2013, 07:45:03 pm: that can be fixed in Photoshop anyway. No biggies.
Title: Re: Strange light trails on long exposure night shot?
Post by: Ken Bennett on May 10, 2013, 09:27:04 pm: One of my favorite photos resulted from my picking up and moving the tripod before the shutter was closed. That's what happened here.
Title: Re: Strange light trails on long exposure night shot?
Post by: Redcrown on May 11, 2013, 12:19:40 am: Thanks, I was pretty confident there was no camera movement (tripod used). But you all may be right. I'll have to test again to be sure.

Reasons I doubted camera movement:

There is a significant trail in the lower left corner, apparently from the faint spectral reflection on the gray car. But there is a brighter reflection on the back of the red car that did not create a trail.

The bright light in the upper left corner did not create a trail.
Title: Re: Strange light trails on long exposure night shot?
Post by: 32BT on May 11, 2013, 02:24:53 am: Does your camera have a shake-reduction feature?
Was it turned on or off when mounted on the tripod?

Did you use a timer, or cable release?
Title: Re: Strange light trails on long exposure night shot?
Post by: Ken Bennett on May 11, 2013, 08:56:24 am: The light trail by the gray car is a light, not the spectral reflection - as you point out, none of the others show that. This isn't "camera movement" the way we usually talk abou it -- this is opening the shutter for a long exposure, then picking up the tripod and walking away just before the shutter closes. (Or taking the camera off the tripod.) Looks like there was some twisting motion, too, as the trails on the bottom left are more circular than those on the top right.