Bulb exposure

First of all, if it matters, I would like to mention that my

question applies only to digital, as I'm not interested in film.

Anyways, I have read about bulb exposure that it is basically

lasting as long as you hold the shutter button pressed. Now some

photoblogs feature pictures with exposures over 10 minutes, from

cameras like Canon 10D or 20D and others. Now, please tell me I'm

stupid, but are those people holding the shutter for a half an hour?

Thanks for the help<br>

<b><a href="http://glimpse.3rror.com">www.glimpse.3rror.com</a></b>

Like with film, a remote release with a locking feature. Potentially they may be using computer control depending on the camera in question.

Pavel with my 10D photos longer than 30 seconds I need my remote switch (RS-80N3). With that switch you can lock the shutter release down for any amount of time.

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Honestly holding the shutter for 1/2 hour might lead to <b>some</b> blurr...

Long digital exposures can have problems with noise and stuck/hot pixels. The good news is the two cameras you mention here have a good track record with these problems for exposures in the 10s of seconds range. Keep in mind that with any electronic camera you will need batteries that are fully charged before attempting a really long exposure. The length of exposure you are talking about can drain a battery very quickly, especialy if you use the dark frame procedure to control noise.

 

- Randy

With the Canon 10D/20D, you can also buy the remote with timer, TS80N3, which allows

you to set exposure length up to 999 hours. I'd recommend an AC Adapter for the camera

for such long exposures, of course. ;-)

 

(BTW, the same Canon timer can be modified to use with a Pentax *istD/DS body as well,

it's just a plug change.)

 

Godfrey

The cable-releases they sell for normal film cameras usually have a little locking screw for just such an occasion, and cost $8-$10 or so. If your camera can use one, it's a simple solution.

 

Had a problem I hadn't thought of a while back. I was doing a 30-minute star-trail picture in Big Bend. So I set the camera on rock, click the shutter open, lock the cable release, and step back out of the way. The problem: Finding the camera again in the dark!