Long exposures on 20D drain batterie?

I am testing with very dark ND filters.

 

Exposure is eg. 30 minutes (lots of noise at 100ISO).

 

I know EOS 5 drain bateries while shutter is open in Bulb mode, but

EOS 3 does not.

 

What about EOS 20D?

 

Thanks in advance

Yes, it will drain the battery. I doubt 30 minutes would drain it completely, however. I have done exposures in cold weather in excess of 60 min with the 10D without completely draining the battery, and my experience with the 20D shows longer battery life.

I run my 10d overnight sometimes. After about 2 hours or so it shuts its self off even if the battery is not 100% dead. In the morning I can still squeeze a little bit of life from it, enough to look at last nights super noisey shot. If you go into PS or a image utility you'll see that all the maximum exposures have the exact same legnth of time listed under the exposere time. 8835 seconds. Most likely the 20d will run it dry or will do the same.

Good application for the AC adapter?

You need power to run the sensor, cpu, memory, etc... Even if the shutter does not require power, you'll still drain the battery.

Thanks for your answers.

Next weekend I will try several shorter exposures and later stacking them to try to reduce noise.

 

Regards