long exposure noise

[calindustries]

I haven't really tried long exposure in a long time (since film). I was playing with my Credo40 back (H mount) last night in some amazing fog. This was my first foray into trying night/long exposures with the Credo.

I was keeping the exposures to under 1 minute and using ISO 50. I was also doing fast exposures between the longer ones (from having read this is good to eliminate stuck pixels).I've noticed that the shadows are a bit noisier than I expected.

Are there any steps to take to try to reduce the noise in long exposures?

Thanks,
Craig (a mostly studio shooter)

[Doug Peterson]

I haven't really tried long exposure in a long time (since film). I was playing with my Credo40 back (H mount) last night in some amazing fog. This was my first foray into trying night/long exposures with the Credo.

I was keeping the exposures to under 1 minute and using ISO 50. I was also doing fast exposures between the longer ones (from having read this is good to eliminate stuck pixels).I've noticed that the shadows are a bit noisier than I expected.

Are there any steps to take to try to reduce the noise in long exposures?

Thanks,

You're using Capture One v7 or v8?

1 min is not a binary-limit. It's the point where it is claimed the quality is still acceptable. I would actually say this number is closer to 40 seconds, but it is of course subjective and dependent on ambient temperature.

How long were your exposures and what was the ambient temperature? How much time passed between long frames?

[calindustries]

It want' too warm or cold here in Brooklyn last night. Most of my exposures were in the 32 second range with a minute or two between. I only took about 20 frames all together. Using v8 C1Pro. They aren't horrible, but they aren't really great.

[Doug Peterson]

I'd need to see raw files to comment further - the JPG of the screen grabs includes compression artifacts, and I prefer to view in raw so i can poke around the file. Feel free to post them here, or, since we are your dealer feel free to call, email, text, tweet, FB, or stop by the office .

At 30 seconds it's pretty important to allow several seconds between frames for heat to dissipate off the sensor. You're close to the 40 seconds I'd normally cite as the longest good quality exposure.

Beautiful scene by the way!

[kurtay]

What aperture were you using? Also why ISO 50? I shot nights at 400 ISO with no grain issues as much as even up to 2 mnts. Although suffer from an odd light reflections here and there. As per aperture, I never use more than f8-10! No needed at night photography as there is no depth of field. Also what was the lens? Wide angle or standard? I Don't have any photograph handy now to post here but I will trying upload one later. My photos are shot with Canon 5d mk II. I don't know about credo backs, wether they are built to shoot outside the studio, may have some limits. These days everything is made for a particular purpose. With film, you'd choose the film, now the digital backs. May be a good idea to check the specs or consult the manufacturer.

[synn]

You cannot compare the long exposure of a CCD back with a CMOS dslr.
The credo does fine at 50 and 100 ISO.

I have managed to get 1 and 2 minute exposures with my credo 40. Yes, there is noise at times, but most of the time this I have managed to clear it in post.

Paul Caldwell gave a good tip that you may wanna try out. After each long exposure shot, shoot a blank 1/500s shot to flush the pixels. Otherwise, the shots will get progressively noisier.

[BernardLanguillier]

Paul Caldwell gave a good tip that you may wanna try out. After each long exposure shot, shoot a blank 1/500s shot to flush the pixels. Otherwise, the shots will get progressively noisier.

I hear that esoteric Buddhist chanting also helps.



Cheers,
Bernard

[synn]

I hear that esoteric Buddhist chanting also helps.



Cheers,
Bernard

Maybe in Japan.
Why don't you get yourself a Credo 40 and give some first hand info?