Olympus X-200, D-560Z, C-350Z Infrared Sensitivity

	Camera: Olympus X-200, D-560Z, C-350Z Filter: none Exposure time: 1/200 F-stop: 3.1 ISO speed: 64 Focal length: 5.8000 White balance: Automatic EV: 11.5522
	Camera: Olympus X-200, D-560Z, C-350Z Filter: Heliopan 715nm IR pass filter Exposure time: 200/100 F-stop: 3.1 ISO speed: 256 Focal length: 5.8000 White Balance: Automatic EV: 0.90839
The specification(s) I have read say that the camera has an ISO rating up to 400. However, I could not get any more than 256. I suppose that ISO 400 is used for shorter exposures - ISO 400 might not be used for long exposures due to too much noise. That said, the picture is a bit too dark. The camera has a night-scene mode, but I found no difference between that and programme auto.