Long Exposure vs. ISO-Noise

FlashMuller · 11-28-2012, 12:39 AM

Hey guys,
this past weekend I was shooting in a very foggy situation. As the shutter speed wasn't of any interest, (mostly I was shooting cityscapes with a tripod) I had the choice between long exposure with low ISO or short exposure with higher ISO. Both ways result in a certain amount of noise. Is there a rule which way to go as the noise may vary?
Thanks

abmj · 11-28-2012, 12:50 AM

When you have the choice, the native (lowest) ISO is best. On Pentax cameras that is 100. At that ISO, even using long exposures on a tripod, noise should be minimal.

elliott · 11-28-2012, 01:25 AM

Also, if you allow dark frame noise reduction to do its thing it will take care of most noise from a long exposure without removing detail like high ISO noise reduction. This requires the camera to take a second exposure of the same length, but with the shutter closed, so it can take a while with really long exposures.

**TomB_tx** · 11-28-2012, 04:58 AM

The dark frame noise reduction is very effective. The Leica M9 also does this (automatically on long exposures) and low ISO night shots are amazing with this technique.

**Ash** · 11-28-2012, 05:17 AM

Shorter exposures may be necessary for your desired effect but exposure must be spot on to minimise high ISO noise. Depends on what camera you use as to what ISO gives acceptable results for longer exposures. Even the K-7/K20D long exposures (>10secs or so) at ISO 200 had discernible noise. The K-5 handles it much better and ISO 1600 images aren't bad even with longer exposures.

11-28-2012, 12:39 AM	#1
FlashMuller Junior Member Join Date: Jul 2012 Posts: 29	Long Exposure vs. ISO-Noise Hey guys, this past weekend I was shooting in a very foggy situation. As the shutter speed wasn't of any interest, (mostly I was shooting cityscapes with a tripod) I had the choice between long exposure with low ISO or short exposure with higher ISO. Both ways result in a certain amount of noise. Is there a rule which way to go as the noise may vary? Thanks

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11-28-2012, 12:50 AM	#2
abmj Veteran Member Join Date: Apr 2010 Location: Central California Posts: 600	When you have the choice, the native (lowest) ISO is best. On Pentax cameras that is 100. At that ISO, even using long exposures on a tripod, noise should be minimal.

11-28-2012, 01:25 AM	#3
elliott Inactive Account Join Date: Dec 2008 Location: North Carolina Photos: Albums Posts: 1,720	Also, if you allow dark frame noise reduction to do its thing it will take care of most noise from a long exposure without removing detail like high ISO noise reduction. This requires the camera to take a second exposure of the same length, but with the shutter closed, so it can take a while with really long exposures.

11-28-2012, 04:58 AM	#4
TomB_tx Loyal Site Supporter Join Date: Jun 2011 Location: Texas Photos: Gallery Posts: 1,446	The dark frame noise reduction is very effective. The Leica M9 also does this (automatically on long exposures) and low ISO night shots are amazing with this technique.

11-28-2012, 05:17 AM	#5
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	Shorter exposures may be necessary for your desired effect but exposure must be spot on to minimise high ISO noise. Depends on what camera you use as to what ISO gives acceptable results for longer exposures. Even the K-7/K20D long exposures (>10secs or so) at ISO 200 had discernible noise. The K-5 handles it much better and ISO 1600 images aren't bad even with longer exposures.