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.