I have just bought a Panasonic DMC-GX1, testing it out in Programme (P) mode which I hoped would behave sensibly, but am finding something odd.

With the kit 14-42 lens (H-PS14042) everything is fine. I took some photos of my daughter in the sunshine and they look superb. The metadata for a typical photo shows 1/250s, f/5, ISO 160 on focal length 14mm.

But I also have the 45-175 power zoom (H-PS45175) and this is where things are going strange. In the same sunny outdoors setting it decided to shoot with 1/2500s, f/18, ISO 12800!! (This is at focal length 72mm). As a result the photo shows very obvious noise, especially on skin tones.

This lens has Optical Image Stabilisation so I don't see why it decided to go with such an excessively short shutter speed; and even if it needed this, why should it close down as far as f/18? This lens is f4-5.6 at maximum aperture.

Camera body firmware is 1.1 and lens firmware is also 1.1. Camera firmware is latest. I see that there is a version 1.2 lens firmware available, but the release notes just say "Speed of AF, consecutive shooting performance of AFC is enhanced in use with DMC-GH3.". No mention of GX1 or of programme mode.

Has anybody seen this before, or have any suggestions for why it might be doing this? Obviously I could just go with aperture priority, but even then I still don't want the camera choosing ridiculous shutter speed and sensitivity.

Many thanks,