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SM3-Threaded Irises

  • Lever or Ring Actuated
  • Ø50 mm (Ø1.97") Maximum Aperture
  • SM3 Threading for Lens Tube Compatibility

Application Idea

SM3D50D Iris Shown Threaded into
SM3L20 Lens Tube and Mounted in
SM3RC Slip Ring on Ø1/2" Post


Lever-Actuated Iris


Ring-Actuated Iris

(Internal SM3 Threads)

(External SM3 Threads)

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SM-Threaded Irises


  • Lever or Ring Aperture Control
  • SM3 (3.035"-40) Internally and Externally Threaded
  • Minimum Aperture: Ø2 mm (Ø0.08")
  • Maximum Aperture: Ø50 mm (Ø1.97")

Our SM3 (3.035"-40) threaded irises are compatible with our Ø3" lens tubes and other SM3-threaded components. Each iris has internal SM threading on one side and external SM threading on the other side. The individual black spring steel leaves pivot within the outer ring of the iris and are designed for long-lasting performance over several thousand cycles.

The SM3D50D ring-actuated iris is designed for integration into confined setups, where the movement of a lever-actuated iris might be obstructed by other components. This iris also features a locking setscrew with a 0.05" (1.3 mm) hex for locking the ring during installation or removal.

Posted Comments:
yuqin.zong  (posted 2016-06-17 16:49:57.31)
Hi Design team, Can you make a 3" ring-activated iris version of SM3D50? It is much better than lever activated iris SM3D50 because a lever activated iris is not light-tight when it is used to construct a tube system. Thank you Yuqin Zong NIST (301) 975-2332
shallwig  (posted 2016-06-20 11:22:51.0)
This is a response from Stefan at Thorlabs. Thank you very much for your inquiry. I will contact you directly to check if we can offer a special here.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
SM3D50 Support Documentation
SM3D50SM3 Lever-Actuated Iris Diaphragm (Ø2 - Ø50 mm)
SM3D50D Support Documentation
SM3D50DNEW!SM3 Ring-Actuated Iris Diaphragm (Ø2 - Ø50 mm)
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