This hand-held shot was taken indoors using a shutter speed of 1/30sec. You can see that the definition is very good.
The noise can become an issue at night if you use a high ISO, so it's best to leave the ISO at 100 or drop it to 80. You can get some very clear shots when you use a tripod and a mid-range aperture value. However, the slowest shutter speed you can use is 16 seconds, and there is no bulb mode. This can make it tricky to set up the exposure for lightning or long light trails.
The EX1 is competent at night photography, but you have to keep the ISO speed down to avoid getting excessive noise. This shot was taken with a shutter speed of 1/2sec and an ISO speed of 80 in aperture priority mode. We didn't use a tripod; instead we rested the camera on a stable surface while holding onto it. The end result is satisfyingly clear.
The other issue is that the aperture can only be closed to f/6.7 and the fastest shutter you can use is 1/1500. This shutter speed limit can make it difficult to shoot in bright conditions, especially if you want to use a large aperture value in order to get plenty of depth of field. And as small as the EX1 is, it's capable of producing plenty of depth of field and nice, blurred backgrounds, especially in macro mode where you can get approximately 4cm away from your subject.