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Gear Talk => EOS Bodies - For Stills => Topic started by: emag on July 05, 2013, 09:24:28 AM

Title: 60D odd behavior after long exposures
Post by: emag on July 05, 2013, 09:24:28 AM
Had the following odd behavior with my 60D yesterday......

Windy day, so we headed to the beach for some long exposure surf photos (1-1.5 minutes) and flash portrait work.  Took the portraits after the surf photos.  I used the 10 second timer to give me time to get in position with the hand-held flash with radio trigger, too windy for stands.  Frequently, the shutter would release and the flash fire as expected and then begin another 10-second countdown and repeat.  More often than not, I had to turn the camera off to get it to stop. 

I have ML on that card but was not using any ML features and made sure of it after the first occurence, nor was bracketing set.  I did note that ML reported a CMOS temperature of 163 and wondered if the camera internals were hot from the long exposures....it wasn't a particularly hot day, low 80's.

I could not get the behavior to repeat after returning home and there is no feel of a sticky shutter release button, nor was there wind blown sand lodged anywhere. 

I'm not overly concerned, as it didn't repeat, but I am curious.  Anyone had similar experience?
Title: Re: 60D odd behavior after long exposures
Post by: BozillaNZ on July 16, 2013, 01:04:27 AM
Long exposure noise reduction

Turn it off. What it does is take another exposure with shutter curtain closed, called 'dark frame' then subtract this frame from your photo, intended to remove hot pixels.

If you shoot RAW you don't need it. hot pixels are easily fixable in almost all RAW processing software.
Title: Re: 60D odd behavior after long exposures
Post by: cbecklund on July 16, 2013, 03:04:15 PM
Long exposure noise reduction

Turn it off. What it does is take another exposure with shutter curtain closed, called 'dark frame' then subtract this frame from your photo, intended to remove hot pixels.

If you shoot RAW you don't need it. hot pixels are easily fixable in almost all RAW processing software.

As far as hot pixels go, I would agree. However as far as noise goes, you cannot remove that much noise in post without loosing a lot of detail. Although long exposure noise reduction is annoying (especially when taking 5+ minute exposures) I think it is worth the time to get an almost noise free image.
Title: Re: 60D odd behavior after long exposures
Post by: BozillaNZ on July 16, 2013, 08:25:45 PM
Long exposure noise reduction

Turn it off. What it does is take another exposure with shutter curtain closed, called 'dark frame' then subtract this frame from your photo, intended to remove hot pixels.

If you shoot RAW you don't need it. hot pixels are easily fixable in almost all RAW processing software.

As far as hot pixels go, I would agree. However as far as noise goes, you cannot remove that much noise in post without loosing a lot of detail. Although long exposure noise reduction is annoying (especially when taking 5+ minute exposures) I think it is worth the time to get an almost noise free image.

Dark frame subtraction only removes hot pixels. It can't cancel out RANDOM noise, which is the major noise in modern sensors. Because noise in each shot are different, and you can't subtract noise from noise to get a noise-free image, the math doesn't work that way.
Title: Re: 60D odd behavior after long exposures
Post by: cbecklund on July 16, 2013, 10:08:58 PM
Long exposure noise reduction

Turn it off. What it does is take another exposure with shutter curtain closed, called 'dark frame' then subtract this frame from your photo, intended to remove hot pixels.

If you shoot RAW you don't need it. hot pixels are easily fixable in almost all RAW processing software.

As far as hot pixels go, I would agree. However as far as noise goes, you cannot remove that much noise in post without loosing a lot of detail. Although long exposure noise reduction is annoying (especially when taking 5+ minute exposures) I think it is worth the time to get an almost noise free image.

Dark frame subtraction only removes hot pixels. It can't cancel out RANDOM noise, which is the major noise in modern sensors. Because noise in each shot are different, and you can't subtract noise from noise to get a noise-free image, the math doesn't work that way.

Ok, well either way, I think it would be a pain to get rid of hot pixels. Here are two pictures, one without long exposure noise reduction, and one with (both at around 8 minutes).