Bahtinov Focus Mask for Samyang / Rokinon 135 F/2
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  • Bahtinov Focus Mask for Samyang / Rokinon 135 F/2
  • Bahtinov Focus Mask for Samyang / Rokinon 135 F/2
  • Bahtinov Focus Mask for Samyang / Rokinon 135 F/2
  • Bahtinov Focus Mask for Samyang / Rokinon 135 F/2

Bahtinov Focus Mask for Samyang / Rokinon 135 F/2

€17.50
Tax included

Pinpoint star focusing for your Samyang / Rokinon 135mm F/2 lens.

  • 🎯 Crisp Spikes at f/2: Optical geometry tuned for high-contrast spikes on bright stars.
  • 🛡️ Soft Felt Liner: Non-abrasive internal ring protects factory lens hoods.
  • 🎨 Color Options: Available in Opaque Black or Translucent Red.
  • 💎 Rugged PETG: Highly resistant to dew, frost, and night conditions.

⚠️ Do not leave under direct sun inside a locked car or sealed telescope cover to prevent heat warping.

couleur / Color: Red
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Bahtinov Focus Mask — Samyang / Rokinon 135mm F/2

Instant micrometric star focusing over lens hood for wide-field astrophotography

At f/2 wide-open aperture, the Samyang / Rokinon 135mm F2 ED UMC is a legendary wide-field astrograph, but its critical focus zone (CFZ) leaves zero margin for error. An approximate focus instantly results in bloated stars and lost contrast on faint nebulae structures. This custom slip-fit Bahtinov mask is the essential tool to lock in sub-millimeter focus by evaluating bright star diffraction spikes directly on your capture screen.

🔬 Precision Geometric Slit Pattern for Fast Optics

✨ Crisp Spikes at f/2

Slit geometry is specifically tailored for the aperture and fast focal ratio of the 135mm lens. The central and cross spikes show up cleanly on-screen, making exact focus alignment unmistakable.

🛡️ Non-Marring Soft Felt Ring

Slips smoothly over the stock factory lens hood. The inner rim is lined with a continuous soft protective felt strip, avoiding plastic-on-plastic scuffs while securing a snug, coaxial friction hold.

Color Options & Weatherproof PETG Polymer

Engineered to handle freezing night runs while delivering a refined aesthetic finish:

  • Two Styling Options: Choose between Opaque Matte Black for maximum stray light blocking or Translucent Red to match the signature red anodized ring of Samyang lenses.
  • Industrial-Grade PETG Print: Highly resilient against humidity, heavy UV exposure, and winter frost conditions.
  • Universal Focus Workflow: Works seamlessly with stock manual focusing, the Azur3dprint manual micro-focusing ring, or as a visual check for electronic focus routines.
☀️ Storage & Thermal Care Advisory:

While PETG exhibits strong thermal stability during outdoor sessions, do not store or leave the mask inside a locked vehicle or sealed under a dark waterproof telescope cover in direct summer sunlight. Extreme greenhouse temperatures (exceeding 70°C / 158°F) can warp fine diffraction slit geometry.

"Focusing the Samyang 135mm by eye on a camera live view screen is notoriously unreliable at f/2. A Bahtinov mask turns guesswork into a clear geometric target: when the central spike intersects the center of the 'X', your focus is locked and your stars will be tack-sharp across the frame."

— Vincent, Founder of Azur3dprint

Technical Specifications

  • Strict Compatibility: Factory lens hood of Samyang 135mm F/2.0 ED UMC and Rokinon 135mm F/2.0.
  • Function: Diffraction-based micrometric focusing assistance on bright stars.
  • Material Matrix: Technical high-durability PETG (UV, dew, and frost resistant).
  • Available Colors: Opaque Black or Translucent Red (selectable in product options).
  • Internal Protection: Integrated soft anti-abrasion felt lining ring.
  • Mount Interface: Direct slip-fit friction fit over lens hood.
REF042

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