Normal photography doesn't require this attachment on the lens.It's only required for a certain specialized use.

Is it for the clandestine photography of secret documents?

AA

This piece of equipment is made by a famous German firm founded in a city whose name begins with W and ends in R.
Although it could be used to photograph documents,it would hardly be clandestine.The lens,attachment and camera body weigh several pounds,about as much as two or three iPads.

Found this entry on-line.
MINOX
Subsidiary of Leica Camera AG.
Headquarters - Wetzlar, (starts with W ends with R)

Makers of small rangefinder 35mm cameras, and famous for their "advanced hobby espionage cameras," updated from the 8x11mm format WWII spy camera. Also makers of lightweight binoculars & camera accessories.

Can't find the item in your challenge though.

AA

It's not made by Minox,although you won't believe how close you came to the actual manufacturer.(they owned Minox at one time)
The attachment on the lens is,itself,as large as a Minox camera.

The accessory in the challenge and it's lens fit this camera from a previous challenge.

Originally Posted by AdmiralAdama

Found this entry on-line.
MINOX
Subsidiary of Leica Camera AG.
Headquarters - Wetzlar, (starts with W ends with R)

Makers of small rangefinder 35mm cameras, and famous for their "advanced hobby espionage cameras," updated from the 8x11mm format WWII spy camera. Also makers of lightweight binoculars & camera accessories.

Can't find the item in your challenge though.

AA

The item in my challenge was not made as an accessory for a spy camera like the Minox.Its manufacturer is best known for its most famous product,the L•••a.They did,for a time,own Minox.It was made to Give users the ability to get "closer" to solving their photographic problems.

The accessory was used with the dual range Summicron lens.

I know nothing about photography. There's a reference with picture of your attachment. It's only described as "an ocular attachment which makes the 8 element Summicron lens fit the Leica M3" camera.

AA

It is an ocular attachment which corrects the viewfinder and rangefinder images when using the near focusing range of the dual range Summicron lens. It was useable on the Leica M3 and most later Leica rangefinder cameras.
Discovering as much as you did while knowing nothing about photography takes a lot of digging around.
Here's an article on the lens.http://www.cameraquest.com/m50dr.htm
I'll award you the challenge.
Take us on the next great adventure,Admiral.