I just got my first 2:1 macro lens. the Laowa 60mm f 2.8 Macro 2:1 in Sony FE mount. The reason I got the lens is that it's the cheapest I could find used at 250 £ with the added bonus of doing 2:1 (I had a look at adapting vintage and DSLR options BUT most of them would cost close to as much if I include the adapter or they wouldn't do 1:1 natively, especially for legacy mounts like Pentax K, Olympus OM, Nikon F or Minolta MD/MC). Though I would have liked to get the APO version because I really really REALLY hate LoCA and how much work it is to remove it in post.
This is a very quick test with little time and care put into it just to see the 2:1 effect:
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The shot at f 22 loses a huge amount of sharpness but it gives me an idea of DoF, which is less the 5mm deep, where it doesn't cover the top of the blue sapphire to the end of the silver frame (top of the image).
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At f 16 it is sharper but the DoF now is more obvious that it doesn't cover the sapphire rock, though I love the cool effect of the inside of the gem as the focus plane is more inside the gem and closer to the silver frame. The ring belonged to my late girlfriend, made of silver with white and blue sapphires from India made by UNICEF. It was her birthday gift (with a pair of earrings and a neckless of a similar design bought from UNICEF) but I stopped wearing her ring this summer because I lost 2 of the white gems on the ring's circumference and I don't want to damage it too much. Now it sits on her neckless around the Aching Arms teddy bear we received from the hospital after losing our daughter. (Coincidentally, yesterday was 1 year since Kim passed away.)