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Hambone Lewinski 5:17pm, 15 December 2007
Simple question: Is there something analogous to reciprocity failure in digital photography when shooting in low-light scenarios?

Jason
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peteSwede PRO 11 years ago
i have absolutely no idea what that means.
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Hambone Lewinski 11 years ago
Ah, I see. So you digital shooters don't have reciprocity issues, but you do have increased noise over long exposures. Shawn, you do a lot of long exposures... have you noticed ever noticed noise issues when you shoot them?

Jason
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HBRstudios 11 years ago
Yeah, reciprocity failure is strictly for us film guys! And the digital long exposures on the latest camera models do a very nice job of eliminating this noise, though the processing time for each image nearly matches the exposure time (ie: if you take an hour long exposure, expect that the camera will need another hour to process and reduce the noise.)

Has anybody timed this on 1-2-3 hour exposures?
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edgeways 11 years ago
That processing time on long exposures is one of the few things i don't like about digital
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Shawn Thompson - Lake Superior Photographer Posted 11 years ago. Edited by Shawn Thompson - Lake Superior Photographer (admin) 11 years ago
Look here for 1 hour plus exposures with the K10d. That's right a stinkin pentax. LOL
vagabondphoto.blogspot.com/search?updated-min=2007-01-01T...

vagabondphoto.blogspot.com/2007/08/dslr-and-star-trails.html
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P.S. You can turn the digital noise reduction off and do it manually in Post Processing.
Take a series of long exposures with the lens cap on. Name them for the time of each exposure - 1hour, 30 minutes, 1.5hours, etc.... then when you do a long exposure you already have a black frame hot pixel map for your exposure time to do noise reduction and hot pixel removal in Photoshop. This means less downtime in the field.
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HBRstudios 11 years ago
Yeah, but what I have heard is that the exposures for the dark frame subtraction need to be shot near the same time as the originals for the hot pixels to match up correctly. Anyone else have info on this? Have you tried it out yourself, Shawn?
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I have yet to try this. You are right though.
A timer or stop watch would be necessary to get the exposures to match correctly. If it was 10 minutes, 20 minutes, 30 minutes, 45 minutes, 60 minutes on the nuts exactly or within a few seconds I would have to think it would work fine.
Truthfully, I like to let the camera do the work for me. LOL
I am lazy like that.
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HBRstudios 11 years ago
And I meant the time BETWEEN exposures (real and dark subtraction) had to be very little -- as least as far as I have heard.
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Sweetlake 11 years ago
Bob West, www.flickr.com/photos/bob_west/ , does a bunch of long exposures and will freely give advice. Check out his stuff, nice.
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Another good topic for the meeting.

Anyone up for a star trails shoot Monday or Tuesday night? I am sure we could start around 7:00-8:00pm.
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Hambone Lewinski 11 years ago
Shawn,

I've had a few too many chilly evening lately, but I would like to get in on star trails sometime... just perhaps after it warms up again.

Jason
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