Much is made of the fact that the G9 is a bit noisy and that noise increases at high ISO settings. In general, I agree. But I disagree with the oft-stated wisdom that the G9 is horrible or, at the very least, unusable above ISO 200. Although I’ll grant that the condemnation or acceptance of noise is largely a matter of taste, I find the G9 to be very usable at ISO 400 – especially if shot in raw mode, properly exposed and processed with noise reduction software. This shot of balloons is from the G9 in raw mode, ISO 400, 1/60 second, f5 using bounce flash. It was converted in Adobe Camera Raw, slightly cropped and tweaked in Photoshop CS3. Noise reduction was accomplished with Noiseware immediately after conversion from raw mode. The Noiseware setting was simply the default.
In my opinion, the G9 produces reasonable 8x10 prints at ISO 400 when shot in raw mode, converted in ACR and treated with Noiseware. In this digital age, many people do not print their photos and, if printed, most photos are printed as snapshots. I’ve posted a 1024x768 pixel version (full screen for many) of the balloons on my Smugmug gallery.
Of course, your mileage – and tastes -- may vary and I have no idea of the noise characteristics of the new G10. But if you have a G9, don’t be afraid to use ISO 400. At the very least, try ISO 400; you may be pleasantly surprised. (In fact, sometimes I use ISO 800 but that's another story ...)