Originally posted by dragonfly
The OP's photos are sharp and in-focus. I think he needs to pay more attention to the metering function of his camera.
I agree, this is a metering issue. People are talking about Vivid settings, which is nothing to do with what the OP is showing in the sample photos.
2cay2, this is common problem for people switching from a point & shoot camera. P&S cameras often can't expose the whole scene without losing detail in the bright or/or dark spots, so they don't try. The camera concentrates on exposing what it thinks you want to take a photo of. This may or may not be what you are actually wanting to photograph.
A Pentax DSLR works correctly: it reads the amount of light in the scene, and then sets an exposure that results in an overall average intensity of 18% gray. This preserves the detail best in dark and light areas. If the scene is mostly a white wall, then the wall will end up looking gray, because the camera wants to see the average exposure as middle gray. That is correct exposure, but probably won't be very appealing.
There are a number of ways to alter the exposure, the easiest being with the exposure compensation button on the camera, but this requires you to learn what exposure compensation is, and when it's needed. It is also common to correct exposures in post-processing, especially if you shoot in raw. The best thing to do is experiment and read and experiment some more. Forget Green mode, it's useless and won't allow you to learn. P-mode is a good starting point for learning.
This tutorial will get you started on correct metering. The Cambridge tutorials are an excellent source of knowledge.
Understanding Camera Metering and Exposure