The ISO test shot in full. All of the crops below are reproduced at 100%.
At ISO 100 the Lumix FZ48 is noise-free, although you can see the effects of processing
Study ISO 200 closely (at pixel level) and you can see some slight softening, but it's really nothing to worry about.
By ISO 400, however, that softening has become more pronounced.
And by ISO 800 noise is also beginning to affect colour saturation as well as detail.
The maximum setting of ISO 1600 sees a significant softening of detail along with a loss of saturation.