C-mount lens to D-mount camera adapter?

[Aapo Lettinen]

It should be easily possible to use C-mount lenses on a D-mount camera with an adapter but finding such an adapter seems to be extremely difficult and I don't want to go through the hassle and expense of getting one custom made. It is weird nothing seems to be available for sale because this kind of adapter is very useful with 8mm cameras.

The idea is to use C-mount lenses on a double8 camera for longer focal lengths and cover the wide angles with normal d-mount lenses so that I can avoid purchasing double lens sets for longer focal lengths and can make extreme telephoto shots with the 8mm cameras of very long telephoto focal lengths which are not available in d-mount.

I remember seeing pictures of such adapters on old hobby camera books but cannot find anything available for sale right now. If you know some place selling them, can you link it here?

[Joerg Polzfusz]

Hi!

I fear that you’ll have to print your own adapter:

https://www.thingiverse.com/thing:2146712

[Don H Marks]

I was looking for the same thing. Just got one on ebay here:

 

325678317500

Edited March 18, 2024 by Don H Marks

[Johnny Liu]

On 3/18/2024 at 8:50 AM, Don H Marks said:

I was looking for the same thing. Just got one on ebay here:

 

325678317500

I just bought the same adapter off of eBay a few weeks ago.  I will try to post an update once I have taken some footage using it on my Bolex B8 handheld.

[Don H Marks]

Mine just came today. 

I don't have a standard C-Mount lens to test yet, but I did measure it and it will likely work. I got these numbers off the internet, not sure how correct they are. 

D-mount flange focal = 12.29
C-mount flange focal = 17.526mm
Difference = 5.236mm 

I measured the adapter and it was about 5.18mm +/- some hundreths. 

The lens I have in mind is the 75mm Yvar, as my Octameter has a setting for 75mm. 

Another I was looking at was the 3"  Wollensak. 

[Don H Marks]

This is not my picture, I found it on the internet. But it does show what I have in mind. You can see the adapter on this one is a vintage piece. Though I can't make the letters other than U.S.A

[Simon Wyss]

ELGEET

[Johnny Liu]

On 3/31/2024 at 4:26 PM, Don H Marks said:

Mine just came today. 

I don't have a standard C-Mount lens to test yet, but I did measure it and it will likely work. I got these numbers off the internet, not sure how correct they are. 

D-mount flange focal = 12.29
C-mount flange focal = 17.526mm
Difference = 5.236mm 

I measured the adapter and it was about 5.18mm +/- some hundreths. 

The lens I have in mind is the 75mm Yvar, as my Octameter has a setting for 75mm. 

Another I was looking at was the 3"  Wollensak. 

Yes, I measured mine and it looks (from my calipers at least) to be correctly made.  I a list of flange focal distance figures to use from this chart:

https://en.wikipedia.org/wiki/Flange_focal_distance

 

[Don H Marks]

I found a 75mm Yvar and it works great on my H8 non-REX with the adapter I got off e-bay.  For those that don't use 8mm, the lens is useable on that camera because the H8 Octameter has a 75mm setting. 

 

After servicing the helicoid, it was easy to re-assemble the lens so the index marks were in the correct positon with the adapter in place. For this camera I want the index marks of all the lenses on the left side. 

 

Edited May 8, 2024 by Don H Marks