Pentax XW 3.5mm 70° Eyepiece

Pentax XW 3.5mm 70° Eyepiece

  (2 Reviews)
✓ 2 year warranty


2x in stock shipped 1-2 working days

About this product

Model:  PentaxXW3.5
Part Number:  70511

The Pentax XW 3.5 is the shortest focal length eyepiece in the XW series with unsurpassed optical clarity and a 70 degree field of view.


  • High-refraction, low-dispersion Lanthanum glass.

  • Pentax Super Multi-Coatings (SMC) on all air/glass surfaces.

  • Edge-blackened optics and optimised baffles minimise internal reflections.

  • Optically corrected for use with focal ratios as fast as f/4.

  • 20mm eye-relief and twist-up rubber-rimmed eyecups - perfect for spectacle wearers.

  • Chromed barrels threaded to accept filters.

  • Weatherproof to JIS Class 4 standards.


Lens Structure:

8 elements, 5 groups

Focal Length:


Apparent Field of View:

70 degrees

Eye Relief:


Attachment Diameter:

1.25" (31.7mm)

Filter Diameter:


Field Stop Diameter:


Eyepiece Ring:

Helicoid type

Height & Width:

5.4" x 2.4"


14.3 oz. (405g)

Eyepiece Field of View Simulator

Customer reviews

Average Rating (2 Reviews):  
Write a Review and share your opinions!

Rating (max 5):  
Pentax XW 10-3.5mm
25 June 2022  | 

Over the past 12 months I have purchased all the XWs in the 10-3.5mm focal length range. They are quite simply the best eyepieces I have ever used. They are built like a tank but don’t feel heavy and the twist-up eyecup mechanism is superbly well executed.

They are extremely comfortable to view through with excellent contrast, colour transmission and control of light scatter. At 70° AFOV they are also about the maximum for my taste and owning non-tracking scopes allows for longer periods of observing when using the drift method. 100% recommend this range.

Rating (max 5):  
Top class eyepiece
13 July 2019  | 

Beautifully engineered eyepiece. Very comfortable, especially the twist-up eye relief adjustment. Extremely sharp view right across the field, which is just right.
Highly recommend for any scope but if you have a fast scope eg Reflector at f5 or faster and have mid-range or telescope stock eyepieces, you will absolutely transform your scope with the XW series.
This is the lowest focal length eyepiece in the series and gives the highest magnification so it is working hard but it produces Fantastically clear and contrasty images with a generous field, nonetheless.


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