After some time away I have re-installed Arch on my piZero. Previously I could run raspistill as a user. However, now I need use sudo.
Having read the wiki have done the following:
Added myself to the video group
In /bootconfig.txt: cma_lwm= cma_hwm= cma_offline_start=
In /etc/modprobe.d/blacklist.conf: blacklist i2c_bcm2708
So what have I missed?