Wel, 50mm/2.8 macro definitely becomes my favorite in K100D. It is fast, sharp, light, and do macro. I spent a little bit over half an hour in Spurlock this afternoon. I always want to take some pictures there. K100D+50/2.8 is a very good combination for that. The SR allows me mostly in iso 800 and 1/25s. And I am very confident to shoot in wide-open in this lens.
The white balance is challenging. The museum's lights are kind of weird and lights in different places has different temperature. Pentax's auto-white-balance is not very well most of the time indoor. But it provides a very useful and handy custom white balance function. I use it all the time. I have to find whatever white place available and I have to use the gray card sometimes bacuse there is no white object to set the custom white-balance. However, to make it worse, the glass of the exhibit often casts some odd shades, which made the gray-card-corrected WB, which can only be done outside the glass, sill quite off. I spent great deal amount of time back in Lightroom to tweak the white balance.
I only walk in the lobby, the Asian room and the small exhibit for Egypt. (Good, leave something for future.) Actually I learned when I was almost done that exhibit for Egypt stuff was not allowed to shot. But they were kindly enough not to ask me to delete them. Anyway here are here.
I really like this Japanese girl doll. The pose, the color and the build is perfect. It is delicate and adorable. I wish that i could record it well in my picture.

This one is in the exhibit of Egypt. It is rudiment yet powerful.

This Chinese wedding march is lovely and it is tiny.