Digital camera: question about noise

The bigger the sensor, the bigger the individual pixels (at a given megapix). The bigger the pixels, the lower the noise at high ISO.
My Canons has a setting which alters the x-y resolution of the image: L, M1, M2, M3, and S on the G10, for example. And another setting which also affects file size: Normal, Fine, and Superfine, which I guess might relate to the JPEG compression.
Now obviously, a low megapix file has lower ultimate resolution than a high one, but will save faster, and you can get more on a memory card.
My question is, if you select the lower resolution settings, does the processing do some combination of the "raw" data and will this reduce the noise on low light / high ISO images? From some not very scientific trials, I'm not convinced of any benefit. So is there any point not using L and Superfine all the time (if you are not trying to shoot fast sequences, and have plenty of memory, and are happy to post-process for web use etc).
No doubt this is discussed somewhere on the web, and I have tried looking but there is a *huge* amount of "noise" out there. Can anyone suggest any good links or "live" newsgroups? alt.photography doesn't seem bad.
TIA
Steve
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On 23/06/2013 20:23, newshound wrote:

In my experience there is rarely any reason other than storage space for using anything but the most pixels and the least compression.
The noise issue relates to the physical sensor pixels so you would not expect any improvement from most settings other than the ISO. The difference occurs when you compare two cameras with markedly different physical sensor sizes.
In these days of multi-gigabyte storage media even storage is not much of an issue.
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On 23/06/13 20:30, polygonum wrote:

+1 Yea, even unto using 'raw mode', if the camera has it. Someone told me, and I believe it to be triue, that the raw images is a lot better than 8 bits deep and you canm sometimes reciocvver acceptable pictures if you process the raw file where the JPEG is 'clipped'

I think that is not what he is talking about. high gain on the CCD tens to introduce random noise into the image. TO an extent reducing te reoslutin will avrege out te 'final' pixle frtom teh adcabnet ones as well.

well I dunno. I put 250GB on the home server and the wife had filled it with random TV recordings in 3 months.
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On 23/06/2013 22:32, The Natural Philosopher wrote:

Indeed re noise - but at least most of what a camera can do is also achievable with post-processing on a computer.
Too true 250GB can easily be filled! But my first digital camera had something silly like 16 MB cards... (or was it even less?) - and at least 4 GB lasts a bit longer even with huge image file sizes, and is cheaper!
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On 23/06/13 23:06, polygonum wrote:

Not if you already lost the data, The point is that te camera takes way? 3x12bit? 3x16 bit and slaps it into 3x 8 bits. Sometimes it simply loses some bits.

yes phots are not as bad as videos. 4Mbyte as against 4Gbyte..
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Not nesser-celery. RAW is stored as at least 12 bit depth, sometimes 14.
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On 24/06/13 09:12, Tim Streater wrote:

sorry, I thought it was obvious that I meant 'when not on raw mode'
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On Mon, 24 Jun 2013 09:12:09 +0100, Tim Streater
Doesn't stand for anything. "raw" will do.
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On 23/06/2013 23:06, polygonum wrote:

My first digital took a 3.5" fdd ...
Not sure if it was mentioned further up thread but I do most of my photography for Scuba ... and noise certainly increases in Low Light ... mainly due to ISO push.
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On 24/06/2013 20:45, Rick Hughes wrote:

Which model was that? All the early ones I remember were CF based and also had a small amount of internal memory so that they could be demo'd in shop without inserting an expensive CF card. Mine was a Kodak DC-120 which was already about as good as the human eye on a 10s exposure.

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Martin Brown wrote:

I've got a DC-50 which is still in full working order, and still has an 8Megabyte PCMCIA memory card in it. 48 pictures....
My first digital camera was the DC20, which got stolen, along with the laptop. 8 pictures at VHS resolution as .bmp files or about 50 jpegs, and transfer them via an RS232 port via a special cable. As they do for the DC50, Kodak still hold the manual online.
The Digital cameras that I know about that took the 3.5" floppies were the Sony Mavica range. They were quite popular at the time with schools, as they needed no special software to read the files, storage was cheap, and they were robust enough to let the kids loose with them.
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On 24/06/13 20:45, Rick Hughes wrote:

I had an underwater film camera for wa while - chap and fun to snorkelling depth.
Do they do cheap digi underwater?
In case I ever get the chance again?
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The Natural Philosopher wrote:

Cases are available for small cameras from under a tenner.....
Decent "Action" cameras come from £130 or so, which will take HD video and 5 megapixel stills in 3 metres of water.
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On 24/06/13 22:08, John Williamson wrote:

That sounds the bunny..
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On 24/06/2013 21:32, The Natural Philosopher wrote:

Panasonic HX WA2 camcorder is rated to 3 metres, will do 14 mpix stills and has quite a few "knobs". £100 on Amazon. Havn't actually tried it underwater, but works well in the rain.
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On 24/06/2013 21:32, The Natural Philosopher wrote:

My phone will do full HD while underwater. I expect there are plenty of cameras that do. How deep do you want to go?

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On 23/06/2013 22:32, The Natural Philosopher wrote:

The only down side is you run out of media faster.

rec.photo.digital isn't bad.

+1

Raw mode is typically about 12-14bits deep and so an N Mpixel image occupies about 1.6N MB. A highest quality JPEG is usually around N/2 MB worst case. Some cameras will save both for you. Saving speed of raw can be an issue if you are doing multiple frame action shots. It is better if getting optimum signal to noise is important to you.
Main advantage of raw is when you know you are facing one time subject material with insane contrast and highlights and shadow detail both matter. Wedding with bride in white and groom in black velvet being the most common serious dynamic range challenge. In camera JPEG default will almost certainly ruin the image with blown highlights.
The only time it is worth using less than the full resolution of the equipment you are carrying is when you are certain you will never need a higher resolution image (eg photo for web/eBay selling) or you would otherwise run out of storage media and have no blanks with you. Given the relatively low cost of sD cards this is not really an issue today.

It is possible that some cameras do bin the data down when certain magic ratios are selected (notably saving at 1/4, 1/9, 1/16 sensor size). Astronomical CCD cameras call this binning and do it to reduce the readout noise. Some of the newest cameras also take dark frames. (ie linear factors of 1/2, 1/3, 1/4)
Some cameras also take their own dark frames on time exposures and do a certain amount of in camera correction for dead/hot pixels etc.
But you can always trade resolution for signal to noise later by low pass filtering in the post processing chain. You cannot however get back the pixel data that was thrown away and never stored.

Stored content will always expand to occupy all the space available.
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On 24/06/2013 10:24, Martin Brown wrote:

Not for me!
Mushrooms. With stark white parts, some (almost black) parts, and lit by a mixture of direct sun, filtered sun and, sometimes, flash.
Amazing what can be dragged out of the shadows. But overexposure, whilst very easy to achieve, is unmanageable.
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On 24/06/13 10:31, polygonum wrote:

Have you tried raw mode and deliberate underexposure?
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On 24/06/2013 11:00, The Natural Philosopher wrote:

Yes - and that is the way to go. I have actually been amazed how well some shots have turned out given the difficult lighting conditions. I prefer the most "natural" lighting possible so only use flash if essential.
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