As much as I wanted a small, moderately wide, native AF lens to be good for colour and infrared on the full spectrum Sony A7 - alas, it was not meant to be. Adapting helps a lot with this Canon 40mm f/2.8 STM as it has great IR performance in a small package. The adapter adds some weight, isn't cheap and has slow focusing on the original A7, but it's probably the best multi spectrum compact AF lens you can get. Since it uses the more standard 52mm filter size I was able to get images like this (below) to compare a ton of different wavelengths.
It may not be as small, light, sharp or anywhere near as quick to focus compared to the Sony/Zess 35mm f/2.8, but it's a fraction of the cost (not including the adapter) and it doesn't suck at infrared.