M3 and Samyang(etc) lenses - shutter wont trip

I tried to test two Samyang/bower/ lenses etc today in a local camera shop and my shutter wouldn't trip. These lenses have no electronic contacts and I wondered if that was the reason why. Initially I thought I had set " dont release shutter without lens attached" but I couldn't find a setting like that in my menu - did I miss it somehow? or maybe it was on another camera.

The two lenses I wanted to have a look at was the 85mm f1.4 and the 500mm f6.3 mirror. Both are going very cheap at the moment.

What I did notice was that even with the aperture on the 85mmmf1.4 stopped down to f22 the image on the lcd was quite clear. It would seem that these mirror less cameras with EVF are tailor made for third party manual focus and manual stop down aperture lenses...if I can just get the shutter to work!

Any suggestions?