My dad picked up a lens at the op-shop a little while ago, and wow it’s heavy. 530grams to be exact. And we had no idea what it was.
It had some interesting markings (some obvious, some not so much, all shown below). F/2.9, 400654, 16 11 8 5.6, 2.9, AM 14A/2445 and J.H.D. 1., which we think was a sticker added afterwards. So off to some random places on the internet we posted and now believe it is a WWII British Air Ministries aerial recon lens of 127mm.
I love to wonder what photos it has taken over the years.