AFAIK Thermal Expert cameras from Korea have adjustable focus and worked very well on PCBs, like smartphone/PC attachments TE-M1, TE-Q1. There were threads on this forum about them. Although once they got EU distributor, incredibly cheap price for performance went up almost 2x, and they will no longer sell from Korea directly to EU. Still even with increased price, price/performance ratio is very good. Seek Thermal also have adjustable focus IIRC but they don't use Germanium lenses for their lower end products and performance is not even close even if resolution spec looks similar.