20D Star Trails - Battery Life

[jcmellen]

I'm wanting to toy around with star trails with the 20D. I've tried

it once many years ago with a film camera and was pretty successful,

want to give the 'ol 20D a whirl at it now. How long of an exposure

can I expect on the 20D before the batteries crap out on me? Also,

if i have the noise reduction custom function on, i'm assuming that

is pointless considering the batteries will probably die, forcing my

shutter closed before the noise reduction even has a chance to

work...is this true?

 

PS, I am using the verticle grip with an extra battery. Am I too

expecting too much to hope for a 3 hour exposure?

[pjmeade]

Hello JC, I recently spent several nights trying to shoot star trails.

I was taking 30 second exposures (because I don't yet have a cable release) and could easily get over 50, after a couple of hundred shots in a days shooting, without a problem. The battery charger would show less that 50% charge when I had finished.

 

I didn't use the noise reduction.

 

Hope this helps. P

[mark u]

Have a look at this site:

 

http://web.canon.jp/Imaging/astro/index-e.html

 

It is not a good plan to try very long exposures (measured into hours) because the sensor noise overwhelms the image, and noise reduction isn't going to solve it. Instead, plan on stacking multiple shorter exposures using a program like Imagestacker. Power problems can be solved with the AC adaptor (if necessary, powered via an invertor from a car battery), but the grip and extra battery will probably be sufficient.

[andrew robertson]

After a while the noise does get crazy. I have taken multiple hours long exposures, and

even with dark frame subtraction, the quality isn't too hot. I did get decent images in very

cold weather, but then battery life issues will intrude.

[dan_stossel]

peter, i was in the same boat as you - no cable release for my 20D. but i figured out a way to create a makeshift "bulb" for exposures longer than 30 seconds. i set focus to infinity (manual focus), then put a tiny wad of crushed paper onto a piece of scotch tape, held my hand over the lens, and basically "taped" the shutter release button down to expose (with the crushed paper providing pressure on the shutter release button) -- then moved hand away to begin exposure, and basically got "bulb" function without a cable release.

 

takes some practice to get the right amount of pressure, but worked well. haven't tried 3 hours yet, but good results with 10-15 minute exposures, and i assume it could hold much longer. maybe a rubber band and a piece of cardboard would work too... :)

 

i suppose i'd fork over the 50 bucks if i ever get motivated enough to do this more than just as an occasional diversion.

 

(and battery wasn't an issue for my exposures, to somewhat address your original question J.C.)

[lancemcvay]

Dan, you're making me feel awful for you! You don't have to spend $50 to get a simple cable release for your 20D. You can buy a knockoff on Ebay for about $10-15. I bought three of them at once so I don't feel to terrible if I happen to leave one somewhere out taking photos at night.

[dan_stossel]

don't feel bad for me, i admit... i'm cheap. just a quick alternative if you suddenly find yourself on a clear night with lots of stars, without a cable release. now if i can only come up with a way to convert my 20D to full frame with only toothpicks and shoe polish...