Canon 7D Question - Built in noise reduction

[dt86vyss]

Hi All,

Probably a silly question, but i must ask as i will never know otherwise.

I have a Canon 7D, those who also have this camera will be aware it has built in noise reduction. My question is... Is it better to leave this functionality disabled and fix any noise in PP?

The reason i ask is that i took some shots at night in Melbourne CBD last week and noticed the quality of my images was far from great, in that the images seemed to be slightly OOF, i thinking it may be the built in noise reduction softening the image mistaking some aspects as 'Noise' when in actual fact it is not.

Just for the record, all my shots where at ISO100 shot at f11-16 and all between 20 and 30 seconds...

[kiwi]

Yes, NR is better done in specialist tools like Dfine, Noise Ninja, Lightroom etc before sharpening

And its definately not a silly question. It's a real tip for getting better images in post processing

[dt86vyss]

Great Kiwi, thanks for that! Off goes the NR then...

[Old Skool]

The 7D long exposure noise reduction options are On, Off or Auto. I would have thought Auto would work OK as I believe it works on long exposures by taking a black frame and subtracting it from the original image. It does this by reading the data on the sensor immediately after the picture is taken (while its covered by the shutter) processing it and then subtracting it from the original image - thus eliminating HOT pixels.
The High ISO noise reduction setting I would set as Standard or Disable as this setting is more likely to soften images.

[I @ M]

Daniel, I reckon you should post one of the "bad" ones as guide to what you mean by out of focus etc.

I am sort of wondering if something like a tram rumbling by even 1/2 a block away isn't causing movement blur at longish exposure times in a relatively busy place like Melb. CBD?

[Pine]

Thanks chaps I did not know of this feature :th3:

Regards

[kiwi]

oh, btw there is a difference between the long exposure NR (which I would recommend) vs the "normal" NR which if shooting JPEG I would recommend turning off, it doesnt matter if shooting RAW, well, I dont think so anyhow.

[agb]

Correct me if I am wrong, but doesn't the noise reduction in camera only apply if you are shooting JPEG, so that if you use RAW none of the in camera settings are applied.

[kiwi]

That's right Graham.

But, I think the long exposure NR does affect the RAW inage too.....I dunno, maybe. :rolleyes:

[dredi1975]

Correct Kiwi, NR does affect RAW images too!
Tried it on my 40D and the longer exposure the worse it appears.....Ive ruined good few shots before I realized it is not necessarily so helpful.

[dt86vyss]

Hi All,

thanks for all the feedback on this one. I note a request for a 'OOF' image to be posted. Note the detailing of the image seems blurry!

http://i366.photobucket.com/albums/oo101/kl_designersandmore/IMG_1405.jpg

http://i366.photobucket.com/albums/oo101/kl_designersandmore/IMG_1435.jpg

http://i366.photobucket.com/albums/oo101/kl_designersandmore/IMG_1419.jpg

[Bennymiata]

When shooting cityscapes at night, the edges around the lights will always be a little fuzzy, and I don't think there is anything you can do about it, unless you underexpose it by a large margin.

I think it is caused by diffraction and the large contrast between the lights and the non-lighted areas.

I've taken shots of cityscapes using the finest macro lens, being extremely cautious about the focussing, and the edges around lights is always blurred slightly.

Anyone else find the same thing?