Endoscopy Camera Coupler 22mm

What it is

The 22mm endoscopy camera coupler is a fixed focal length optical adapter that couples an endoscopy camera head (with a C-mount interface) to the eyepiece of a rigid sinuscope or endoscope. It contains a relay lens system with a 22mm focal length optimised to project the endoscope image onto the camera sensor with appropriate magnification and field coverage for most standard rigid scopes. The proximal end attaches to the camera head C-mount; the distal end fits over the endoscope eyepiece.

When & how it's used

Used as the mechanical and optical interface between the sinuscope eyepiece and the endoscopy camera head in all video endoscopy setups. Without a coupler, the camera cannot attach to the scope. The 22mm focal length is optimised for most 4mm rigid sinuscopes and provides the correct magnification and image circle to fill the camera sensor without vignetting (black edges) or cropping the endoscopic field of view.

The camera coupler is a component that receives little attention compared to the scope and camera head, but it is critical to image quality: a poorly matched or low-quality coupler introduces vignetting, chromatic aberration, image distortion, and loss of resolution that degrades the output of even a high-quality scope and camera. The 22mm focal length in this coupler is chosen because it provides the optimal projection of the endoscope image circle onto the sensor format of most standard endoscopy camera heads — filling the sensor without cropping the field of view and maintaining sharp focus from centre to edge of the frame.

In practical use, the coupler is threaded onto the camera head’s C-mount and then seated onto the scope eyepiece (typically with a friction fit or locking ring). Focusing is achieved by rotating the coupler body to adjust the distance between the relay lens and the eyepiece, bringing the endoscopic image into focus on the camera sensor. Once focused for a given scope and camera combination, the setting is typically maintained. The 22mm fixed focal coupler is the standard choice for routine FESS and diagnostic nasal endoscopy; for departments that need magnification adjustment without moving the scope, the HD zoom coupler provides variable focal length.

Design features

• 22mm fixed focal length: Optimised relay lens projection for most 4mm rigid sinuscopes and standard endoscopy camera sensors.
• C-mount camera interface: Standard C-mount thread connects to the vast majority of endoscopy camera heads.
• Focusing adjustment: Rotatable coupler body allows fine focus adjustment between the relay lens and the scope eyepiece.
• Stainless steel construction: Durable, autoclavable; maintains optical alignment across repeated sterilisation cycles.
• Eyepiece compatibility: Fits standard rigid sinuscope and endoscope eyepiece diameters.

Frequently Asked Questions

What does the focal length of a camera coupler determine? The focal length determines the magnification at which the endoscope image is projected onto the camera sensor. A 22mm focal length provides approximately 1:1 reproduction for most standard 4mm scopes, filling the camera sensor with the endoscopic field without vignetting or over-magnification. A shorter focal length would crop the field; a longer focal length would reduce magnification, potentially leaving the sensor partially unfilled.

Will this coupler fit any endoscopy camera? It fits any camera head with a standard C-mount interface, which is the most common interface for endoscopy cameras. Camera heads with proprietary interfaces specific to a particular manufacturer’s system (e.g., some Storz or Olympus integrated camera-scope systems) may not accept a standard C-mount coupler.

When should I choose the zoom coupler over this fixed 22mm coupler? The fixed 22mm coupler is the appropriate choice when a consistent, calibrated image is preferred and scope-to-scope variation is acceptable. The zoom coupler (18mm–35mm) is preferred when different scopes with different eyepiece geometries are used on the same camera, when variable magnification for close-up or wider-field work is needed, or when the system is used across multiple surgical specialties.

Does the coupler need to be sterilised? Couplers are handled outside the sterile field in most endoscopy setups and are therefore not routinely sterilised between cases. They are wiped with an approved disinfectant wipe. If the coupler enters the sterile field during a procedure, it must be sterilised beforehand. Check compatibility with the sterilisation method before autoclaving optical components.