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-   -   Time lapse at night preparation (https://www.dvinfo.net/forum/canon-xl1s-xl1-watchdog/2729-time-lapse-night-preparation.html)

Keith Loh July 17th, 2002 11:53 PM

Time lapse at night preparation
 
One of the first things I wish to try when I get up to speed with my XL1s is time lapse photography at night to get some pretty star movement a la "Baraka". I've picked out a nice place that is fairly free of 'light pollution'. What kind of things should I prepare for this in terms of shooting and equipment?

Obviously a tripod. I'm looking at models now. Do they all allow a decent elevation for shooting up into the sky?

How about a battery? What kind of battery will last eight hours of night? Maybe even more (for lead in).

Assuming the standard kit lens (I'm sure a wideangle would be better but this is not in my budget right now), what settings would be optimal for the image?

I've already found this article: http://www.shootingdigital.info/xl1s2article.htm which addresses some of the problems but it doesn't address shooting at night.

There is also this article: http://www.soc.org/opcam/09_fw9697/mg09_timelps.html

which addresses time lapse issues with film. At the end of the article there are ten points the author makes that are pretty common sense such as marking off the area, getting permission, feeding yourself, etc.

Dylan Couper July 17th, 2002 11:59 PM

Hey Keith, you can borrow my 3x lens if you like.


PS. Watch out for bears! :)

Keith Loh July 18th, 2002 12:22 AM

I might take you up on that, Dylan.

As for bears. I think I'd only have to watch out for the human kind. I'll be shooting in Iona Park.

Joe Redifer July 18th, 2002 12:33 AM

Don't forget an 8 hour DV tape! Or will you be recording straight to a hard drive? I suggest putting the camera on the slowest shutter setting so that when there is any movement in front of the lens the picture "blurs". This is actually very helpful for timelapse videography. That way it won't look as stuttery when complete... it'll have a bit of motion blur to it and it'll look more natural.

Ken Tanaka July 18th, 2002 12:44 AM

OK you guys, just make sure you practice safe lens-swapping. <g>

Seriously, though, I envy you. Living in the middle of a big city, the last time I saw stars was when I walked into a door during a nocturnal trip to the bathroom. I've wondered if film, with its higher resolution, might not be a better medium for star shots. Let me know how the star-shoot comes out.

Keith Loh July 18th, 2002 01:29 AM

<<<-- Originally posted by Joe Redifer : Don't forget an 8 hour DV tape! Or will you be recording straight to a hard drive? I suggest putting the camera on the slowest shutter setting so that when there is any movement in front of the lens the picture "blurs". This is actually very helpful for timelapse videography. That way it won't look as stuttery when complete... it'll have a bit of motion blur to it and it'll look more natural. -->>>

Very helpful. Believe it or not, I hadn't even considered a longer tape. I guess my mind is still in the 3D mode where it only writes to the hard drive whenever there is something to write. I won't have a laptop with me so, yeah, I will need a DV tape. Do I have to worry about speeds?

I figured having the slowest shutter speed would have that effect. I know the director in that film link I posted did the same but I wasn't sure if that could be done with the XL1s. That's now newbie I am.

Keith Loh July 18th, 2002 01:30 AM

<<<--
Seriously, though, I envy you. Living in the middle of a big city, the last time I saw stars was when I walked into a door during a nocturnal trip to the bathroom. I've wondered if film, with its higher resolution, might not be a better medium for star shots. Let me know how the star-shoot comes out. -->>>

That's one of the great things about Vancouver. An hours drive or less and you're right in the middle of the great outdoors.

Film indeed would be better for star shots. Then you can actually play with types of film, speeds, as well to get a better effect.

Keith Loh July 18th, 2002 01:41 AM

<<<-- Originally posted by Joe Redifer : Don't forget an 8 hour DV tape! Or will you be recording straight to a hard drive? -->>>

Uh.. is there such a thing as an 8 hour DV tape? The longest I've been able to find is 80 minutes. If so, could you not swap tapes during the night? For some reason I had the idea that in time lapse mode that the XL1s would record an interval frame not actually film for 8 hours??

Robert Knecht Schmidt July 18th, 2002 05:06 AM

I'm surprised nobody's mentioned this yet, but, uh.... I'd be very surprised indeed if any exposure time setting on the XL1 was long enough for the signal to outweigh the noise of dark current on the CCD. In other words, you'll never be able to do nighttime time lapse using an XL1. If you prove me wrong, please post footage--should be interesting.

Jeff Donald July 18th, 2002 05:44 AM

It's been several years since I read about this. Astronomers are using CCD images for night time work. It goes something like this: turn gain to -3db, shoot the scene, capture footage, take frames into Photshop and sandwhich together. In otherwords the underexposed images with low noise are combined until normal exposure is obtained for the highlights (stars, planets).

Jeff

Keith Loh July 18th, 2002 09:17 AM

<<<-- Originally posted by Robert K S : I'm surprised nobody's mentioned this yet, but, uh.... I'd be very surprised indeed if any exposure time setting on the XL1 was long enough for the signal to outweigh the noise of dark current on the CCD. In other words, you'll never be able to do nighttime time lapse using an XL1. If you prove me wrong, please post footage--should be interesting. -->>>

Sounds like a worthy challenge! I will have to research more.

Keith Loh July 18th, 2002 11:19 AM

<<<-- Originally posted by jtdonald : It's been several years since I read about this. Astronomers are using CCD images for night time work. It goes something like this: turn gain to -3db, shoot the scene, capture footage, take frames into Photshop and sandwhich together. In otherwords the underexposed images with low noise are combined until normal exposure is obtained for the highlights (stars, planets).
-->>>

This explains why my searches for 'stars' and 'CCDs' always brought up astronomy sites. I assumed it was just a scientific term and I never explored those links.

Jeff Donald July 18th, 2002 11:31 AM

In response to Roberts question about noise and grain in the image, astronomers actually cool the CCD and other chips to minimize the noise. i've seen pictures printed in magazines using the method i described and they are amazing.

Jeff

Keith Loh July 18th, 2002 11:42 AM

Star exposure is possible
 
I was able to contact John Bushey who wrote the first article I linked to. He does photography using the Xl1s in Yellowstone. He wrote in reply to my query:

>"Keith,
>
>I have tried time lapse on the XL1S at night with stars. I needed to
>boost the gain to +30 to get a good number of stars to show up. The
>test I did was at 7000 feet in the Rockies so I was closer to them
>than normal (g). You may not have as good as results as I did
>because you may have more layers of atmosphic "junk" than I did. Not
>only was I very high, but I was far away from light and air pollution
>sources like cities.
>
>I did not get the "star tracks" that are common on still photography
>of stars. I was shooting at 1/30 of a second as I recall so that
>would explain the lack of "tracks". If you wanted the tracks to
>appear, it seems like it would be easy to add using an NLE in post
>production. "Fix it in Post" is my ByLine (g)."

So it does work. Eventually I will see if I can replicate his experience.

Jeff Donald July 18th, 2002 12:02 PM

If your after the circular tracks of stars, produced by the earths rotation, it would be much easier with a still camera. They are a single image, not a series of images like video. His "Fix it in Post" is an excellant suggestion for star trails.

Jeff


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