This ring allows adjusting distances with more precision as with extension tubes. It fits above the T2 filter thread of your adapter.
Fields of use:
- Optimal back focus adjustment between camera / off-axis guider/corrector
- Prevents threads from blocking
- Too long T2 threads can be shortened
Technical details:
- Stainless steel
- 0.3, 0.5, 1, 1.5 mm thick (depends on the model)
- Inner bore diameter:
- 42,1mm (M-42 version)
- 49mm (M-48 version)
- Outer diameter: 55 mm:
- 55mm (M-42 version)
- 60mm (M-48 version)
