Pentax SMC XW 3.5mm 1.25" eyepiece (12339)

Pentax XW-Series eyepieces are high-performance, wide-angle eyepieces designed for use with premium spotting scopes and telescopes. These eyepieces provide a wide 70° apparent field of view and a generous 20mm eye relief, ensuring clear and comfortable viewing even for users who wear glasses. The advanced optical design uses high-refraction, extra-low-dispersion lanthanum glass elements to deliver sharp, well-balanced images with minimal aberrations. The XW-series is specifically engineered to reduce the blackout effect by compensating for the spherical aberration of the pupil, resulting in a more stable and immersive viewing experience.

All air-contact lens surfaces are treated with Pentax’s original multi-layer coatings, while laminated surfaces receive a partial coating to achieve outstanding light transmission-over 90% across the visible spectrum and up to 96% at 550nm. Advanced light-shielding technology is used to minimize internal reflections, providing brighter, higher-contrast images. The eyepieces are weatherproof to JIS Class 4 standards, making them suitable for use in damp or dewy outdoor conditions, though they are not intended for underwater use. The series offers a selection of focal lengths to suit various observation needs, including models specially designed for astronomical use.

These eyepieces combine advanced optical engineering, wide-angle comfort, and robust weatherproofing, making them an excellent choice for both terrestrial and astronomical observation.

Key Features:

• 70° apparent field of view for a wide, immersive image

• 20mm eye relief for comfortable viewing, even with glasses

• High-refraction, extra-low-dispersion lanthanum glass elements for excellent image quality

• Multi-layer coatings on all air-contact surfaces for superior light transmission

• Advanced light-shielding diaphragm for improved image contrast

• Weatherproof construction (JIS Class 4) for reliable outdoor use

• Rotatable, adjustable eyepiece cup for added user comfort

• Compatible with optional camera adapters and filters

Specifications:

• Apparent field of view: 70°

• Focal length: 3.5 mm

• Eye relief: 20 mm

• Number of lenses: 8

• Number of groups: 5

• Telescope connection: 1.25"

• Camera end connector: M43

• Optical coating: Multiple coatings

• Light transmission: 96% at 550 nm

• Field stop: 4.3 mm

• Adjustable eyepiece cup: Yes (rotatable)

• Optional camera adapter: Yes

• Filter thread: Yes

• Inert gas charge: No

• Series: XW

• Weight: 405 g

• Length: 137 mm

• Diameter: 61 mm

• Type: Eyepiece

• Build: Super Wide Angle (SWA)