What thread is this adapter on a CS-mount lens?
Asked 12/23/2024
5 views
2 answers
0
I bought a camera that came with a lens marked “1.25" CS IR 3MP.” The lens has an additional threaded adapter on the front/end, and I measured the external thread at about 30.68 mm diameter with calipers and roughly 0.75 mm pitch. I first wondered if it was C-mount, but C-mount is usually 1"-32 TPI, which doesn’t match this outer measurement. What thread is this likely to be?
Originally by Rocketmagnet. Source · Licensed CC BY-SA 4.0
Rocketmagnet
1y ago
2 Answers
2
It really looks like the lens is a CS-mount lens. It's printed right on the side: 1.25" CS IR 3MP.
It appears the black threads are a thread adapter, with internal C-mount threads (1-inch × 32 TPI, "1-32UN-2A" specification). The outside threads are probably a 30 mm, maybe 30.5 mm thread? With a thread pitch of 0.75 mm that you think, it's probably M30×0.75. I would have said possibly a Thor Labs SM30 mount (M30.5×0.5), but not with the 0.75 thread pitch you have.
If it weren't for the fact that you've measured correctly, I would assume the adapter was using a TFL mount thread (M35×0.75 mm). Is basically "C-mount, but larger throat), because it's flange distance of 17.526 mm is the same as the C-mount's flange distance.
Originally by scottbb. Source · Licensed CC BY-SA 4.0
scottbb
1y ago
0
Generated from our catalog & community — verify before relying on it.
The lens itself appears to be a CS-mount lens — it’s labeled that way. CS-mount uses the same 1"-32 thread form as C-mount, but with a shorter flange distance.
What you measured is most likely not the native lens mount, but an adapter ring fitted over it. Based on the dimensions you gave, the outer thread is probably around M30×0.75 (possibly 30.5 mm nominal, but your measured pitch points more toward M30×0.75 than SM30/M30.5×0.5).
So in short:
- Lens mount: CS-mount
- Underlying mount thread: same thread form as C-mount, 1"-32 TPI
- Outer thread you measured: likely an adapter, probably M30×0.75
It does not sound like TFL mount, which is typically M35×0.75 and would be much larger.
Recommended products
UniqueBot
AI1y ago
Your Answer
Related Questions
How can I estimate an object's real size from pixel size, focal length, and subject distance?
Why does a rear-mounted C-mount filter prevent focus on a CS-mount camera?
Do I need a step-up or step-down ring to use a larger filter on a smaller lens?
Can I attach a Panasonic Lumix G7 with the 14-42mm kit lens to a 1.25" telescope eyepiece?
Can you use C-mount CCTV lenses on Micro Four Thirds with an adapter?