At ISO 100 the TZ30 keeps noise at bay.
ISO 200 shows a minor loss of detail, but the image is still intact.
At ISO 400 the image begins to soften as noise begins to creep in.
At ISO 800 the TZ30's built-in noise-reduction has begun to noticeably soften detail in an effort to control noise.
By ISO 1600 noise is quite visible throughout the image.
The top setting of ISO 3200 is both noisy and soft.
Taking the TZ30 out of the studio for a moment, here's how it performs when faced with a 'real-world' low-light situation. Note that all of the following images were taken using a tripod and the TZ30's self-timer.
Using ISO 100 as the benchmark, the TZ30 has produced a pleasing twilight picture of Trebarwith Strand.
At ISO 800, the TZ30 can still capture a reasonable image, although it is pretty soft.
At ISO 1600 the image is noticeably soft and grainy - even at reduced sizes.
By ISO 3200 image quality has degraded considerably.