What lens is this cap for?

[KyleCharles]

Hi all.

Last fall I was given a bag with a Contax IIIa, Opton 50/2, and 35/2.5 & 135/3.5 Nikkors. The lenses are in beautiful condition with mint glass.

Also in the bag were some odds & ends (filters, hoods etc.). I'm trying to find out what lens the cap pictured on the right is for. On the left is the cap for the 50/2 that I included for size comparison. The mystery cap is 2 inches wide (50 or 51mm). It is not lined with felt around the rim like the 50/2 cap. It is in NOS, (never been mounted on a lens even once) condition.

So any idea what lens this is for? Any idea of it's approximate value?

 

[KyleCharles]

Could this be a body cap? Looks to be the exact right size, but I won't put it on the camera so I can retain it's virginity.

 

[Fred R.]

Looks like the cap to fit the 21 biogon.

 

[johank]

No the 21 mm has the same Cover as 2/5cm and 1,5/5cm however the 2/8,5cm Sonnar needs a 50,8 inner diameter Cover, so does the Jupiter 9.

The post War 3,5cm 2,8 has a Cover with inner diameter 50,5. Fabric on inner rim.

 

[hilltime]

Yes, it is a body cap for the IIA or IIIA. I have the exact cap and packaging, but I have used mine. Works like a charm!

 

[KyleCharles]

Thank you!

 

[Vics]

Not so fast! Does the camera work? Are you going to use it?

 

[KyleCharles]

Yes, the camera works but I'm not going to use it. It fires, but the speeds sound off and I'm not willing to spend the money on a CLA at this time. The focus helicoid is very stiff and the camera has been dropped/dented as well. To be honest, I don't really like the camera all that much. I much prefer my Leica IIf 1/1000 and my M2 to the Contax IIIa. I purchased a Amedeo Contax/LTM adapter so I can use the beautiful Contax mount glass on my Leicas.
The IIIa bundle belonged to my friend's late father, so even though I won't use the camera, I can't sell it either. However, I have decided that I can sell the accessories (like this body cap) without feeling guilty. The cap and other assorted accessories are mint NOS and really belong in the hands of a collector. Any idea what a fair price for a NOS body cap like this might be?

My friend's late father was a USAF colonel during the Korean war. Sometime soon I will be be seeing the photos he took during the war with this camera. As a pilot, airplane nerd, and vintage camera enthusiast, I'm pretty excited on many levels to see these photos!