Since the recent camera update I've had nothing but trouble with the built in Google camera app. After I take a picture the Nexus 5 will often freeze with all 4 cores of the CPU churning away. The only way to restore the phone is to reboot. I don't know if it is a bug in the program or a conflict with another app or something to do with my xprivacy settings.
I tried settings / apps and "uninstall updates", reboot, but that didn't help. I finally gave up and now use "cameraMX" app which lets me take pictures without freezing the phone. So I'm OK but I wonder if others have had the same experience. I also would like to get the apk of the kitkat camera app before the latest update to install and try. Anyone have it?