"High ISO Noise Reduction"

I've just found this in my K-m's menus. Is there any reason not to crank it up all the way, other than some people liking noise in the same way that they liked grain on film?

It does exactly what it claims to do, I'm just worried that it might be doing something horrible to my photos that I haven't noticed yet!

I think one thing it does it take longer for images to be written to the card. Not noticeable on short exposures but if you do a long night shot it could take a while.

See for yourself what happens link

It doesn't affect the RAW files, so have a play. For me the top two settings are too 'smudging' of detail (on the K200d) - and I shoot RAW if noise is going to be an issue in any case.

Hmm, I might turn it down to medium then. I usually shoot JPG as I find that most of the time the results are fine, it's faster and you can fit an awful lot more images on a given SD card. I will be using RAW for one-off events in future though as it does allow you to rescue wonky shots.