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Pentax - XW-3.5 Eyepiece - DISCONTINUED

Model#: 70511

Discontinued Product

Manufactured by: Pentax


This is a discontinued item. We recommend the Olivon 70° 3.5mm Wide Field Eyepiece as a replacement.


The PENTAX XW 3.5 boasts a 70 degree field of view for easier viewing, optical clarity second to none in its class and the shortest focal length in the XW series.

All Pentax XW eyepieces are manufactured with high-refraction, low-dispertion lanthanum glass which delivers high-resolution, bright images with maximum aclarity and minimum distortion. Additionally, the XW-series eyepieces meet JIS Class 4 weather standards, thus increasing their durability regardless of atmospheric conditions. 

XW-eyepieces are designed to be used with a broad range of of Pentax spotting scopes and telescopes. Expect Pentax quality and clarity whether your application is astronomical or Earth-bound. 

Product Series

PENTAX Corporation is pleased to announce the introduction of the smc PENTAX XW series of eyepieces designed for use with PENTAX-brand spotting scopes and telescopes in ground and astronomical observations. Consisting of eight models with a focal length ranging from 3.5mm to 40mm, the new XW series features a wide apparent angle of view (70 degrees), JIS Class 4 weather-proof construction and a long eye relief (20mm). The new optics, incorporating high-refraction, low-dispersion lanthanum glass elements and PENTAX-original multi-layer coating, delivers bright, high-resolution images with minimal aberrations and distortions.

The new XW series retains all the popular features of the current XL series, including eyepiece shape, while upgrading many vital specifications. All XW models feature a 70-degree apparent angle of view, delivering a more dramatic, wide-perspective image than the 65 degrees of the XL series. Laminated optical elements are treated with the innovative partial coating, which offers much higher light transmission capability than conventional full-surface coating. Thanks to advanced computer simulation technology, internal reflections are drastically reduced to produce brighter, clearer images. Replacing the existing XL series, the new XW series can be used with the PENTAX PF-80ED, PF-80EDA and PF-100ED spotting scopes and a range of PENTAX telescopes to optimize their performance and capability. The XW7, XW10, XW14 and XW20 models are suited for both ground and astronomical applications, while the XW3.5, XW5, XW30 and XW40 models are exclusively designed for astronomical observations. # Improved 70 degree field of view for easier viewing # XW 7,10, 14, 20 will give a wider field of view than our previous eyepieces when used on Pentax Spotting Scopes or with telescopes. # WX 14, 20, 30, and 40 are designed specifically provide ideal viewing conditions when used with a telescope # Fully multi-coated lenses increase light transmission and color quality # High-refraction, low-dispersion lanthanum glass elements deliver bright, high-resolution images with minimal aberrations and distortions # Advanced computer simulation design technology was used to drastically reduce internal reflections producing brighter, clearer images # JIS Class 4 weather proof construction makes these eyepieces more durable # Long eye-relief for viewing with or without glasses # Limited Lifetime Warranty

Additional Information

Name Pentax - XW-3.5 Eyepiece - DISCONTINUED
Manufacturer Pentax
Model 70511
Discountinued Yes
Diameter 1.25" (31.7mm)
Dimensions 5.4\" x 2.4\"
Eyepiece Apparent FOV 70
Eyepiece Apparent FOV2 0
Eyepiece Barrel Size 1.25"
Eyepiece Eye Relief 20
Eyepiece Eye Relief 2 0
Eyepiece Focal Length 3.5
Eyepiece Focal Length2 0.0
Eyepiece Elements 8
Eyepiece Ring Helicoid type
Field Stop Diameter 4.3mm
Field of View - Apparent 70 degrees
No. of Elements 8 elements, 5 groups
Weight in Use 14.3 oz. (405g)