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01-29-2008, 11:19 AM   #16
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QuoteOriginally posted by TravellingLight Quote
Only true for some film cameras. For instance, the Z-1 was reputed to flatten its battery in a 20-30 minute exposure. Many of these high tech film cameras energise an electromagnet while the shutter is open, causing quite high current drain.

The Pentax 67 can be modified to mechanical mirror lock up rather than electric for people who do a lot of long exposure work.

Colin
Makes me pine for my T90. Electrically operated shutter, yet it used permanent magnets to hold the shutter open. So long Bulb exposures had almost zero current drain while open. The shutter closed when the small electromagnets briefly energized, destroying the permanent magnets' field, allowing the shutter to close.

It was very nice...

01-29-2008, 11:22 AM   #17
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QuoteOriginally posted by m8o Quote
A Film camera barely has any power drain. 1 second to one hour exposure is probably the same power drain on the battery.
That is a function of camera, My KX has zero because it does not need a battery, I am not so sure about my PZ-1.
01-29-2008, 12:05 PM   #18
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QuoteOriginally posted by TravellingLight Quote
Only true for some film cameras. For instance, the Z-1 was reputed to flatten its battery in a 20-30 minute exposure. Many of these high tech film cameras energise an electromagnet while the shutter is open, causing quite high current drain.
The Pentax 67 can be modified to mechanical mirror lock up rather than electric for people who do a lot of long exposure work.
Colin
Thanx for the edjamacation. I didn't have the good sense to get into photography in the film days.

Good thing about that situation tho is you still get an exposed picture on the film @ the end of it. Maybe not properly exposed if you did the math and were shooting for proper foreground exposure too, and/or were 'painting' the scene with a light; but for star trails, you'd still get something.

Actually, I wonder if these digitals K10/100/110 have a safety feature that completes the picture when the battery is getting low? Wonder if you go to take say a 30 second exposure, if it'll save the picture if it only has enough juice for a 10 second exposure and a file save... Tough one to test; gotta get the timing just right.
05-12-2008, 04:06 PM   #19
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Don't think so...

QuoteOriginally posted by m8o Quote
Actually, I wonder if these digitals K10/100/110 have a safety feature that completes the picture when the battery is getting low? Wonder if you go to take say a 30 second exposure, if it'll save the picture if it only has enough juice for a 10 second exposure and a file save... Tough one to test; gotta get the timing just right.
I kind of doubt it. I've lost pictures due to long exposures and the battery going dead on me in my *ist DL. So, I kind of doubt my K10D has any kind of picture save based on battery level.

It is one way to learn to make sure your batteries are fresh before heading out for some night photos, be they earth-bound or astrophotograhy.

For what it's worth, I routinely use the bulb with astrophotography, even when shooting under 31 seconds. It's just easier to set to bulb mode and play with the timing than it is to constantly adjust the timing on the camera. The best way, even though I don't always do it myself, is to use the setting that lets you trigger the shutter then delays for 2 seconds or so before taking the shot. And get a remote that can lock the shutter or you'll still have a tired finger!

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