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Old Mar 7, 2003, 9:13 PM   #1
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Default Increasing Shutter Speeds...

Is there a way to extend my maximum shutter speed from 16 seconds to maybe 30 or 60 seconds?

I'm experimenting with star-trail photography, and I'm finding that the short 16 shutter, coupled with a long disk-write time is not very effective.

OR, if someone at least has any suggestions in decreasing the disk-write time per image. I take a 16 second exposure, and it takes another 16 seconds to write it on disk.

TIA,

Oz
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Old Mar 7, 2003, 9:20 PM   #2
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I imagine the maximum shutter speed is hardcoded into the firmware, so even if the C-4000 (which is what I assume you are using) is physically capable of longer shutters, it couldn't be changed by us consumers.

Are you shooting the stars in Night Scene mode? Or do you have the noise reduction mode on in manual mode? Both of these conditions will add the significant delay you've experienced to the processing & writing speed.

I have tried taking night shots with slow shutter speed in manual mode without the noise reduction feature on, and the results were rather horrible. MUCH better with the NR mode on.

I don't know if any consumer digital cameras have bulb shutter feature (one click opens the shutter, the next one closes it--preferably with remote control). My $250 film SLR does, but I haven't used it yet. I'm sure $2000 digital SLRs do, too! :shock:
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Old Mar 7, 2003, 9:26 PM   #3
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The problem with longer exposures is more noise due to a hotter CCD, some cameras reduce the risk of this by only offering shorter exposures. As for write time, you can shorten that by using SHQ JPEG or HQ JPEG rather than TIFF...with smaller files it will take less time to write to the card.
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Old Mar 7, 2003, 9:41 PM   #4
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Take a look at Max Lyons' Stacker program at http://www.tawbaware.com/ A good site to vist once in a while.
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Old Mar 7, 2003, 9:50 PM   #5
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Quote:
OR, if someone at least has any suggestions in decreasing the disk-write time per image. I take a 16 second exposure, and it takes another 16 seconds to write it on disk.
Is this what most camera do to reduce noise under long exposure? ie the camera takes a first shot @ 16s, then a second 16s shot with the shutter close to subtract out the noise of the 'dark current'. http://megapixel.net/html/issueindex.php?lang=en
Quote:
... uses a noise reduction system, as is now commonly found on other cameras with bulb or long exposure capability. After the long exposure is taken, the camera automatically captures a second, similar length exposure without opening the shutter. It then uses the noise information gathered from it to eliminate most of the noise in the first exposure.
It can not be the write time since the file size hasn't change mostly between a 1/1600s, 1/16s, or 16s shots... It's still a 4Mp camera! :lol:

I don't know if you can stack the pictures though since this is a moving streak and you'll be missing 1/2 of the shot. The reason there's usually a max limit is this is a long time and requires LARGE counters when clocks @ microseconds unit of fast camera processor's clock! Even in bulb some digital camera will set a max limit which you can not exceed... (or no NR may be) ops: ops: ops:
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Old Mar 7, 2003, 11:16 PM   #6
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NHL -> You just hit the nail right on the head!! As soon as you mentioned about creating a 16second darkframe, I immediately shot a 16sec. exposure without Noise Reduction, and it worked like a charm! Only took the camera about 1 second (not even, I think) to write on the disk. When the skies clear up here again, I'll be taking another shot to see how it turns out. Thanks-a-bunch!

BillDrew -> Yes, I am using Image Stacker. The problem - as I pointed out to NHL - is the extra 16sec. darkframe exposure for each 16sec. shot I take. I get a 16sec. exposure in 32sec. real-time. When I brought the images to Image Stacker to brighten the pixels, I get this (copy & paste to a new window):

http://www.imagestation.com/picture/...d.jpg.orig.jpg


Best to view it in 100% (ie. actual pixels). When you look at the star-trails, you'll see the problem the 16sec. darkframe exposure causes. But now that disabling NR will speed up disk-writing considerably, the star-trails should appear as a trail. I guess I'll have to rely on Image Stacker's dark-frame reduction instead for noise-reduction.

Mike_Peat -> I shot in 640x480 SQ2 JPEG and 640x480 TIFF, and it still was quite a long time before my next shot. However, the SQ2 JPEG with a 128MB card allows me to take roughly 1500 or so images, which should be great for star-trail photography (time to by that li-ion pack...hehehehe).

Hyun -> Yes, I am referring to the C-4000. When I do night scenes, I almost always use Manual Priority, especially with star-trails. Consumer-affordable digicams can offer a bulb shutter. This is what I like about the NikonCoolpix 4500, which was only about $200CAD more than the C-4000. The 4500 is capable of a 30sec. timed exposure, or up to 8 minutes bulb exposure. I did email OlympusAmerica last month asking this question, and all I got was a simple BS run-around type answer. "There are no firmware update plans available for the C-4000" was all I got. They didn't even bother to explain to me if the camera components can handle longer than 16sec.


Thanks-a-bunch guys. I hope to have something in the near future. Just gotta wait for these clouds to get out of the way!



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Old Mar 8, 2003, 6:37 AM   #7
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That's a great picture. Must try this stacking thing, never heard of it till now.
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Old Mar 8, 2003, 6:56 AM   #8
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Just downloaded Image Stacker and read about it.

It mentions moon-lit reflections, exactly what I was trying to do a few weeks ago and couldn't get enough light. Never thought of stacking never mind a program that does it for you.

I know this lake which often has an eerie misty glow to it late at night - my next assignment.

If only I could get more clear skys here.
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Old Mar 8, 2003, 9:16 PM   #9
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Quote:
Originally Posted by steve6
Just downloaded Image Stacker and read about it.

It mentions moon-lit reflections, exactly what I was trying to do a few weeks ago and couldn't get enough light. Never thought of stacking never mind a program that does it for you.

I know this lake which often has an eerie misty glow to it late at night - my next assignment.

If only I could get more clear skys here.
I find that the "Stack" option is quite effective when I take multiple underexposed shots of the same subject. I really haven't noticed an improvement when using the Dark-frame reduction feature, but then again, all of my images so far are already noise-reduced by the camera. Maybe my next outing will test that.



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