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Cage System Iris Diaphragms

  • 30 mm or 60 mm Cage System Compatible Irises
  • Continuously Variable Lever-Actuated Aperture
  • Button Head Lever Allows Actuation while Iris is Installed


For 30 mm
Cage Systems


For 60 mm
Cage Systems

Application Idea

CP20S Iris in a Cage System with
KCB1C Right-Angle Kinematic Mount and
CP02 Cage Plate Holding an SM1L10 Lens Tube

Related Items

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Thorlabs’ Cage System Irises are designed for use within a cage system. The button head lever on these irises clears the fourth cage rod, allowing for aperture adjustments within the cage system.


  • One-Piece Irises for 30 mm or 60 mm Cage System
  • Continuously Variable Iris Diaphragms
    • CP20S: Ø0.8 mm to Ø20.0 mm Aperture
    • LCP50S: Ø2.0 mm to Ø50.0 mm Aperture
  • Ultra-Thin Cage Plate Design
    • CP20S: 0.25" (6.3 mm) Thick
    • LCP50S: 0.33" (8.3 mm) Thick
  • Black-Anodized Aluminum Housing Limits Reflection

These lever-actuated, continuously variable, cage-system-compatible iris diaphragms are designed to provide smooth operation over many thousands of cycles. These irises are mounted in ultra-thin, cage-system-compatible plates that engage three cage rods with a flexure mechanism that tightens using a 5/64" (2.0 mm) hex. The steel leaves that comprise the iris are actuated by a button head lever that clears the fourth cage rod, as shown in the picture to the right, allowing for operation within a cage system. These large-aperture irises provide the maximum aperture available for use within a cage system and are permanently installed in the cage plates.

In addition to the cage system irises sold on this page, our SM-Threaded Ring-Actuated Irises can also be utilized in a cage system with the use of an SM-threaded cage plate. However, the cage system irises featured on this page offer larger apertures and thinner profiles than the ring-actuated irises. For non-cage system use, we also offer Post-Mountable Irises, SM-Threaded Lever-Actuated Irises, and Unmounted Irises with no mounting holes.

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Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
CP20S Support Documentation
CP20SCustomer Inspired! 30 mm Cage System Iris Diaphragm (Ø0.8 - Ø20 mm)
LCP50S Support Documentation
LCP50SCustomer Inspired! 60 mm Cage System Iris Diaphragm (Ø2 - Ø50 mm)
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