When taking pictures of winter landscapes there are two problems which I do not understand fully:

I use a Sony T1 (with which I am very happy), but these effects are slightly disturbing. My question is: what can I do against it?

Read up on exposure. Your camera exposure meter is a reflective meter that wants to meter things to 18% gray (neutral). If you're taking a picture of a scene that is not neutral toned (bright skies, snow, caves, etc) you will over or underexpose your shot. Camera meters that use matrix or evaluative mode are fairly good at capturing the right exposure most of the time, but are fooled when the scene is dominantly bright or dark. One thing you can do to overcome this is to use partial or spot metering and lock your exposure on a neutral tone, then recomponse and take your picture. Knowing when to override your camera's exposure meter is critical to consistant success with your pictures. I strongly suggest that you read as much as you can on this subject. There are plenty of books available, as well as tutorials online. Try a search for "exposure" and see what you get. One good source to start is http://luminous-landscape.com/tutori...exposure.shtml

If by rays you mean visible lines of light on your image, you may need to look into a polarizer filter (which will also help with your blue skies) and/or a lens hood.

Yes - there are four symmetrical visible lines (like diagonals of a rectangle) coming from the sun.

Using a polarizer filter on a camera such as the T1 (like Minolta Dimage) seems not practible to me. Since I used a Canon Digital Elph 400 before which showed none of the two effects (sky blue was saturated, no artificial rays) I wonder if there has been a polarizer filter "built in".

Thank you very much for your reply - I will do as you suggest. It seems that only by tweaking with my camera's settings the colors will get right - and I have to live with the sun-"rays".

Likely the "rays" are flare. A polarizer might help, but main solution is to keep the sun from shining on your lens. Not always possible, and not always that distracting. The sun is in the upper right corner of this photo with a "stream" of flare images in line toward the center. It is caused by internal reflections within the set of lenses - the patern will be different for different lenses.

This image has different adjustments to the sky vs the lower part of the image. Without doing that, the sky would be washed out.
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Image is a three shot pano roughly equiv to using a 17mm (equv) lens.

I thougt of this reason before since I took similar pictures with my Canon s400 with absolutely no artificial "rays" or flare. Here are two sample pictures of my Sony DSC-T1 flare which could be produced by the internal prism/lens-system (the minolta dimage xt should produce similar pictures).
The second picture shows my "pale blue sky"-problem: the sky was much more saturated in reality.

Interesting... I think part of the problem in the second picture could be because the lens flare is so big. The effect is not just a point or ray, but an entire blob washing out the sun... it also lightens the area around it... the sky. Notice how the sky is a bit darker way over on the right? It might not be as dark as you'd like (the polarizer would help with that) but it is darker.

And people are right, that is serious lens flare, no question about it. Cameras have more or less flare depending on their physical makeup, so your older camera might just have been better that way. You can help combat this by blocking the direct sunlight into the camera... but in these pictures the sun is in the picture so you can't do this. But this is what a lens hood does. Prevents the stray light from directly going into the lens and bouncing around (which is what causes flare.)

Taking pictures of snow is not easy. One you learn some tricks it will get better... but camera metering systems often don't handle it well. Luckly for you, you can take many pictures at different settings and see which ones worked out.

Eric