Bahtinov Focus Mask for Sigma 30mm f/1.4 DC DN Contemporary (Sony E-mount)

This mask is made to fit into the same mounting slots used by the original lens hood , providing correct centering and a secure, repeatable fit — no tape, adapters or friction fitting needed.

Designed for astrophotography, the mask generates a clear Bahtinov diffraction pattern that makes precise focus on stars quick and easy, especially when shooting wide open at f/1.4 , where accurate focus is critical.

Updated:

v1.4: - Improved mounting design for smoother and easier installation. v1.2 - Added a textured, gear-style outer ring . This makes it much easier to grip and remove the mask in the dark without touching the lens barrel or accidentally shifting focus.

The added ridged surface improves handling with cold fingers or gloves and helps avoid unwanted movement of the focus ring after precise star focusing.

This change does not affect the optical pattern — only usability and handling.

Features:

- Designed for Sigma 30mm f/1.4 DC DN Contemporary (Sony E-mount APS-C). Not suitable for full-frame.

- Mounts in lens hood slots

- Accurate optical alignment

- Easy to install and remove in the dark

- Lightweight and travel-friendly

- Optimized spike geometry for small-aperture camera lenses

Printing Tips:

- Material: PLA / PETG

- Layer height: 0.28 mm works well

- Suppotrs are required

- Print flat on the mask face

- Dark filament recommended to reduce reflections

Usage: Place the mask on the lens, point at a bright star, zoom into live view, and adjust focus until the central diffraction spike is perfectly centered between the other two.