Noise question

admirable

admirable

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Jim
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Would increasing the jpeg quality/compression also increase noise?
 
It'll certainly make the noise appear more destructive. It'll slowly turn it more blocky than grainy!
 
Noise results from the sensor gain being increased so JPEG compression has no effect on the amount of noise read from the sensor. As Phil says, the effect that the sensor noise has on the final output will become more apparent as the compression is increased.

Bob
 
I turned up the jpeg quality setting on the 1D from 8 to 10 and the noise is a lot more noticeable, just wondered if that was the cause.
 
You've basically reduced the compression of the JPEG so I wouldn't have thought would have affected the noise in the image. It would probably been roughly the same for both compressions I would have thought. I wonder if it's something else you are seeing rather than noise? Although I must admit I can't think what at the moment
 
Update;

turned the jpeg quality setting back down from 10 to 8 and all is well and back to normal!

So the obvious question is 'what does that setting actually do'?

confused :thinking:
 
Noise is basically unwanted detail - detail that should not be there. By reducing the JPEG quality you are applying more compression (throwing more information away) to the image file and some of the detail, including noise, begins to disappear.
 
So what is the point of having a setting that goes up to 10 when 8 is enough? When should 10 be used?
 
tdodd said:
Noise is basically unwanted detail - detail that should not be there. By reducing the JPEG quality you are applying more compression (throwing more information away) to the image file and some of the detail, including noise, begins to disappear.
Click to expand...

Tim is absolutely correct. Just wanted to add to OP that you can think of it like this: increasing compression for JPEG is similar to reducing image resolution (due to the way JPEG encodes) - and by doing that your are effectively averaging those "unwanted details" (noise) out.
 
Canon state that image quality will be high at setting 10. This is not so in my case. The quality of the image was reduced when set to 10 from 8 mainly due to what looked like noise. Or am I missing something?
 
JPEG is a "lossy" file format. It throws away (loses) image detail. The more you compress a file the more detail and quality you lose. If you shoot to JPEG in camera then immediately you have thrown away data before you can get your hands on the file for any further processing. This is one reason that many people prefer to shoot raw rather than JPEG.

A quality setting of 10 means that you are throwing away less of the image data than a quality setting of 8. The file will be (much?) larger but may or may not contain additional useful information. If you have scenes that are devoid of much detail - e.g. the paintwork of a car - then losing detail may not matter a great deal. If you have scenes that contain considerable detail - e.g. a landscape with grass in the foreground and middle ground - then you may wish to preserve as much fine detail as possible.

Noise is really a separate issue altogether and should be dealt with separately. The first question is - what is the caause of the noise? Is it needlessly high ISO? Is it underexposure at capture? The 1D3 is a cracking performer as far as noise is concerned, and all other aspects of IQ. Noise oughtn't to be a problem unless shooting in the most miserable of conditions. The best way to deal with noise is to prevent it occurring in the first place, with proper consideration of exposure settings at the time of capture. The second best way to deal with noise is by using noise reduction settings either within the camera or in software afterwards. IMHO simply increasing JPEG compression is not the right solution to masking noise.

If you want to address noise after capture, in the best way possible, then you will do well to shoot raw and then you leave yourself as much flexibility to fix the noise as you see fit, whether using settings within your raw converter software or using dedicated NR software such as Neat Image, Noise Ninja etc.. But you should always aim to get that exposure correct in the first place.

Can you post an example of a typical problem image, without edits, and with EXIF attached? Then maybe we can offer some further advice. I'll go first....

Here is a shot with my 1D3 at 3200 ISO, 1/60, f/3.5. Flash was used. This was shot raw and has had no edits other than a white balance adjustment and +0.4 exposure in Lightroom. Everything else, including noise reduction and sharpening, is at Lightroom defaults.

Full image....
20090418_203745_6834_LR.jpg
20090527_100526_0007_LR.jpg


100% crop....
20090418_203745_6834_LR.jpg


With some attention to noise reduction in post I'm sure this image could look very smooth indeed, but when viewed at normal levels of magnification rather than 100% the noise is a non issue, even at 3200 ISO.
 
admirable said:
So what is the point of having a setting that goes up to 10 when 8 is enough? When should 10 be used?
Click to expand...

At the base ISO the highest setting will give you the highest quality with little compression artefacts. Increased compression will have an appearance of reduced noise at a higher ISOs but remember it is still a compression that throws away not just noise but the details as well.

If this is the utmost quality you are after, then I'd suggest you use RAW not JPEG
 
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