I'm new to anamorphic shooting and have bought a very nice Isco. It worked well with my CZJ DDR Tessar 2.8/50 on a 600D via M42 adapter, but today I took receipt of a new 5D3 and after mounting said lens it wouldn't operate at all - instead stuck on a " could't find firmware update" screen.
A quick search on google reveals a potentially more lethal outcome - apparently the 5D3's mirror will hit the back of many M42 lenses. So I've immediately put my eBay wishlist of vintage lenses on hold and, failing to find a definitive list/guide on compatible lenses, am now turning to ask the more knowledgeable folk here. Kindly advise.