M68M to M42M Adapter – 1.4mm Back Focus
This precision-machined M68M to M42M adapter is designed for astrophotography setups that require extremely accurate back focus spacing. With an ultra-short optical length of just 1.4mm, it’s ideal for fine-tuning imaging trains involving reducers, flatteners, filter wheels, off-axis guiders, and cameras.

Finished in matte black to help minimise internal reflections, this adapter provides a clean conversion from an M68 threaded system to standard M42 (T-thread) while preserving critical spacing requirements.
Key Features
- M68 male to M42 male (T-thread) thread conversion
- Ultra-thin 1.4mm back focus for precise spacing control
- CNC-machined for accuracy and durability
- Matte black finish to reduce reflections
- Ideal for advanced astrophotography imaging trains
Specifications
- Thread A: M68 × 1 (Male)
- Thread B: M42 × 0.75 (Male, T-thread)
- Optical / Mechanical Length: 1.4 mm
- Material: Aluminium alloy
- Finish: Black anodised
What’s Included
- 1 × M68M to M42M Adapter (1.4mm back focus)