Long Exposures and noise

fret_wimp2

I was out around the Sam Beckett bridge last night with my DSLR. It looks like an amazing landmark, but its supprizingly difficult to get a nice shot of. I didnt come home with one single photo im happy with.

My issue though is noise. I was doing 6-10 second exposures to get car light trails. All my images (particularly the sky, clouds lit by orange street lights) look really really noisy.

Ive done long exposure in the countriside before without that particular issue.

Is it just a case that long exposure causes noise in very dark portions of the photo, such as the sky at night? I was aware of this but never saw it as this bad.

Im thinking also, it was a hazy night so there could have been a lot of light refracted around, making the sky look more orange and noisier.

Have you experienced this and what methods do you do to combat ( shorter exposures, tools etc)

5uspect

fret_wimp2 wrote: »

I was out around the Sam Beckett bridge last night with my DSLR. It looks like an amazing landmark, but its supprizingly difficult to get a nice shot of. I didnt come home with one single photo im happy with.

My issue though is noise. I was doing 6-10 second exposures to get car light trails. All my images (particularly the sky, clouds lit by orange street lights) look really really noisy.

Ive done long exposure in the countriside before without that particular issue.

Is it just a case that long exposure causes noise in very dark portions of the photo, such as the sky at night? I was aware of this but never saw it as this bad.

Im thinking also, it was a hazy night so there could have been a lot of light refracted around, making the sky look more orange and noisier.

Have you experienced this and what methods do you do to combat ( shorter exposures, tools etc)

Enable long exposure noise reduction in your camera. The sensor can heat up and can promote pattern noise. It should be in the custom functions.

fret_wimp2

5uspect wrote: »

Enable long exposure noise reduction in your camera. The sensor can heat up and can promote pattern noise. It should be in the custom functions.

Awesome! I didnt know that fn existed on the camera! Cant wait to give it a go!

Thanks!

magicbastarder

what camera do you have? they would not all have long exposure NR.

AnCatDubh

fret_wimp2 wrote: »

Is it just a case that long exposure causes noise in very dark portions of the photo, such as the sky at night? I was aware of this but never saw it as this bad.

Noise hangs out in shadows.

By any chance was your ISO bumped above 100?

6-10 seconds doesn't sound excessive but different cameras will perform to varying degrees - some of the pro level stuff you can shoot in next to complete darkness with beautiful results (which is why they are pro level stuff).

fret_wimp2

I have a Canon 5D Mk II, lowest iso (250 i believe).

Its strange, as at xmas i did a 7 min complete night exposure & there was hardly any noise. I was very impressed.

But in the city, when there is a lot of moisture in the air for the orange street lights to bounce off, there seems to be a lot more noise for a much shorter exposure.

I think its a combo of factors. At xmas it was much much colder (-2). Also there was zero ambient light/light pollution. the fact that the sky is not black, but a sickly orange, the camera struggles to bring detail out where really, there should be none and so it gets noisier.

I need better noise reduction techniques in my processing phase anyway, as PSE Denoise just isnt cutting the mustard. Il have to do some learning to find a different denoise technique that gives better results.

5uspect

Lowest ISO on the mkII is 100 (or 50 with expansion enabled)

Also the noise reduction tools in newer versions of Camera Raw/Lightroom are excellent

thelungs

If shooting using tripod make sure image stabilization is turned off on your lens.

challengemaster

5uspect wrote: »

Lowest ISO on the mkII is 100 (or 50 with expansion enabled)

Also the noise reduction tools in newer versions of Camera Raw/Lightroom are excellent

Yeah, I'd be going the Camera Raw route for noise reduction, rather than worrying about it in-camera (as long as its not extremely excessive)

bernard0368

You can also try exposing to the right, helps on the 7d so may help on the 5d

enda1

challengemaster wrote: »

Yeah, I'd be going the Camera Raw route for noise reduction, rather than worrying about it in-camera (as long as its not extremely excessive)

But the in-camera one basically takes a closed shutter photo of the same exposure time and subtracts it from the image. SO I think they are not mutually independent features and both could be attempted.

fret_wimp2

By camera raw, you mean when i open a raw file in photoshop for the first time and i do processing of the actual raw file?

5uspect

fret_wimp2 wrote: »

By camera raw, you mean when i open a raw file in photoshop for the first time and i do processing of the actual raw file?

Yes, the RAW editor in Photoshop is called Camera RAW.