“ Pentax / eyepiece 14mm „
Pentax have long been synonymous with quality and as with anything else in this world quality does have it's price. In the XW 14mm's case it's a rather hefty £250 price tag.
That may seem an extortionate amount to pay for an eyepiece but you must remember what you're paying for. If crisp, sharp and wide field views is what you're after then look no further than this little gem from Pentax.
Traditionally it is desirable to use the fewest amount of lenses (or elements as they're known) in an optical system. The more glass that's introduced the more degraded the image, however, there are occasions when more lenses can increase the field of view of an eyepiece dramatically.
That's what Pentax have done with the XW, they have used a total of 7 elements arranged in 3 groups of 2 and one single lens. This has enabled them to wrench a 70 degree field of view from the eyepiece.
To get around the problem of adding extra glass, Pentax have used a very high quality lanthanum glass to minimise aberrations such as light scatter or inferior contrast.
A common complaint amongst wide field eyepieces is that the image quality starts to degrade in the outer portions of the field of view. The Pentax stays pin sharp right to the very fringes of the field.
When observing faint galaxies you'll be astounded by how much light this eyepiece manges to funnel into your eyeball. Not only that but the contrast in the XW is phenomenal. Even the most elusive deep sky objects are resolved cleanly and sharply through the entire field.
Optically this eyepiece is a real winner but what use is optical brilliance if the eyepiece is uncomfortable to look through. Thankfully Pentax haven't neglected that side of things and the XW is just as much of a joy to look through as it is optically excellent.
There is a generous 20mm of eye relief (eye relief is the distance one must hold ones head from the lens to see the entire field of view). 20mm is more than enough to accommodate even the bespectacled astronomer. A good eye relief coupled with a large field stop make the XW a really comfortable eyepiece to look through.
The XW 14mm yields best results on faint galaxies where it outperforms the majority of similarly priced eyepieces in similar focal lengths. Highly recommended.