How long does your Canon DSLR battery last

[JohnH]

I have noticed that my Canon20d battery seems to run low very quickly when I use the supplied EOS capture software, ie by the time I focus and do a 10*30s imagaing run (NR on at iso 800 or 1600) the battery has pretty much had it. That is from a fully charged start.. If I use my TC80N3 to run an imaging session it lasts for many more shots, of course then the images are not being sent up the USB cable to the PC. Is USB a power hog? If yes how is this best solved - currently I use two batteries - must I get the AC adapter?

[acropolite]

Not sure as I haven't used it in that mode, but the quoted manufacturers specs for numbers of shots is fairly accurate, my 20D seems to get very good life between charges. 10x30 Seconds doesn't sound right though.

[Vermin]

If you have 12V available it's fairly easy (and cheap <$10) to convert it to the required 7.8V DC in to the camera using an adjustable linear regulator IC.

[JohnH]

Thanks Vermin, how would I do that exactly - I will need a connector to the 20d as well. AFAIK there is no external power port so I need battery shell to make the connection - where would I get such a thing?

I guess from your response that shooting under PC control via USB does use more power than using internal storage?

[Vermin]

I don't have the camera (yet) so I can't comment on the power usage.

However if it was due to the USB driver I thought a circuit like this: http://casemods.pointofnoreturn.org/vregtut/tutorial-full.html would do the job. I did not realise that the camera had no DC port.

Sort of stymies that idea.

[rowena]

are you using the camera hooked up to a computer????

I get about 2hrs battery time, with most of that with a open appeture/exposing time out of my 300D.

5 minutes sounds wrong! it could be a faulty battery! Id suggest trying another battery to see if you get the same problem.

[Striker]

With my 20DA I get around 30-40 x 30 second exposure but when doing long exposure like I did at Lostock the battery lasted all night...I took around 25 x 10 minute exposure with the same battery...it seemms like most of the power is used starting and finsihing the exposure instead of how long the exposure is.

[Vermin]

Definitely the finishing, if you are saving as jpeg, the DSP (digital signal processing) from the raw image data would be the most power hungry bit.

[Gama]

I beg to differ, i used 1 battery for the nights session with 30 x 1 minute exposures and downloaded them by USB to the computer running DSLR Focus V, and it still had half a charge to go.
So i would bend towards the battery being a problem. When they go, they go fast.

There pretty cheap on ebay, i got 6 for $10.00 each. They work great, as long as you cycle them by using them 1 at a time, and not 1 all the time.
That way all batteries get good use and you have more spares rather than throwing them away 1 at a time.
Use your old one and strip it and install a regulator in it to use for really long nights.

Just a final thought, are you using mirror lockup ?.. if not, you should, as theres a drain for current alone.

[Vermin]

I certainly wasn't discounting the battery being a problem, just commenting on Striker's observation.

[JohnH]

Thanks guys. I have two batteries - both about 18 months old now, I guess they are getting tired, and I was using JPEG (I know, I know) and I was not using mirror lock. I like the I idea of the $10 replacements - and I will use an old case to make a DC connector.