Originally posted by shuttervelocity But of course. The XT is very old, but since its lower MP than the T2i, its pixel density is higher. That should theoretically translate to better pictures in low-light conditions. And it does produce very good pictures even in dim lighting. But the lack of features like live-view wants me to upgrade. I already did the snapsort comparison and it was re-assuring to see that the K-r is the winner.
I have been hunting for a lesser pixel modern-day camera and the K-r fits right in. Everyone's caught up in the megapixels war. Heck the dsc-hx9v fits right in my pant pocket and boasts 16.2 MP!
Megapixels is probably the worst metric people use to judge a camera, but they do so out of familiarity. It's one of the metrics that people first learn. As for the size of the pixels on the XT, and how that translates, it's not entirely a good thing. Yes, the photosites should be larger, but it's also using an older sensor technology which won't be as good as more modern ones, and it's using a much older processor and firmware, which won't control noise as well as current.
Realistically, a T2i should produce better output, even in low light, despite the smaller pixels on its 18MP sensor. It has much improved software processing the output, and I'd be shocked if the sensor itself weren't a much better quality just due to the 5 years between them.
Comparing the T2i and K-r is easier. They're both approximately the same generation of camera, and have comparable levels of processing going on. The larger photosites on the K-r's 12MP sensor *might* give some small edge in low light performance, it certainly doesn't hurt. I think the most dramatic differences are in how the two sensors handle colours, and how the two processing engines differ (especially if shooting jpeg). For a lot of people the differences will boil down to personal preference more than anything, rather than an objective win for either.
From your posts, I think you'll be happy with the K-r. There is a whole list of reasons why it's advantageous over the T2i and its rivals, but honestly, the sensor itself is probably pretty low on that list.