T2 extension tube (T-adapter) with M42x0.75mm thread on both ends, 40mm in length



This T2 extension tube (T-adapter) can be used to connect DSLR cameras to spotting scopes or telescopes with M42x0.75mm male thread on top of the scope eyepiece or on the scope’s focuser. This adapter works together with a camera T-ring (also known as T2 mount) which can be ordered from this store, or with a 1.25″ or 2″ T-adapter as an extension barrel.

This tube enables you to securely set the spacing between the T-ring (i.e., your DSLR camera) and the telescope at 40mm. Such a projection ratio (camera-to-eyepiece separation) can be required for some digi-scoping systems. For example, Panasonic Lumix G camera will need this tube (and a micro 4/3 T-ring) to work on Celestron Ultima 100 spotting scope, as well as on other scope models that have M42x0.75mm thread on top of the eyepieces (under the rubber eyecup).

There are internal T2 threads on both ends of the tube, with one end having M42x0.75mm male thread (for the connection of camera T-rings/T2 mount), and the other side having M42x0.75mm female thread (for the connection of eyepieces). Many scopes have got a M42x0.75mm male thread either on top of the eyepiece (under the rubber eyecup), or on the eyepiece holder / focuser near the scope body.

The tube also has full internal threading and blackening to prevent any stray light reflections.


  • M42x0.75mm threads on both ends.
  • Projection ratio (camera-eyepiece separation): 40mm
  • Built with metal material and black anodized.
  • Full internal threading and blackening for the prevention of any stray light reflections.
  • Dimensions:
    • Internal tube diameter: 37.5mm (Note: this is the maximum eyepiece diameter that can be held within this tube)
    • Spacing (camera-eyepiece separation): 40mm
    • Overall length: 45mm


A range of T2 mount (camera T-rings) can be ordered from this store: Nikon, Canon, Pentax K, Sony, Olympus 4/3, Micro 4/3 (for Olympus and Panasonic Lumix G cameras with Micro 4/3 lens mount).

This T2 extension tube can work with a 1.25″ or 2″ T-adapter barrel for image focus purpose.

Additional information

Weight 0.15 kg


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