Pentax XW 30mm, 20mm, and 14mm Review
By: Vlad Fedosov
Pentax eyepieces are not ones that you hear about too often or run into at a star party. They do seem to have somewhat of a cult following and a select few that swear by them. When I had a chance to test out a Pentax XW 30mm, 20mm, and 14mm I was more than delighted to! The XW line of eyepieces have a relatively wide 70° Field of View(FOV) and a generous 20mm eye relief. Let’s dive in and see how these guys do under the night sky!
I will start by talking a bit about the overall build and feel of the eyepieces. More so than most other eyepieces that I have come across these eyepieces look and feel different. What do I mean by that??? Well most other eyepieces, to me at least, can be mistaken for coming from the same factory. They look and feel very similar with a chrome barrel, black metal body, and the typical diamond texture rubber grip. The Pentax units do employ a chrome barrel like the other brands but have a very curious and almost camera lens-feeling polymer body. An eyecup seems to be omitted for those used to the typical rubber ordeal found on most eyepieces. But the Pentax does indeed have an adjustable height volcano-style eyecup. More on this later. Overall I would say that I do like how the Pentax feels in the hand, though perhaps not as solid as a TeleVue due to the polymer body.
Moving on to the optical aspect of the eyepieces, I tested them with a William Optics FLT-132 f/7, and a Takahashi TOA-130 F/7.7. The testing was done on and off over several months at my semi-dark sky home in the NW. The first impression that you get by taking a look through the eyepieces is that the view is crisp, contrasty, and very easy to take in due to the long eye relief!
Zeroing in on the sharpness and contrast, I would say that I felt that these eyepieces perform very well compared to the Explore Scientific eyepieces I use as my primary set and the many TeleVue eyepieces that I have tested over the years. This is speaking strictly of the center of the FOV. Unfortunately, things get a little messy when looking at the outer FOV:( Unfortunately, these eyepieces suffer from a surprising amount of coma(where stars look more like little comets rather than pinpoints). The 30mm was the worst in this regard with at last 40% of the outer FOV! The 20mm, and 14mm are better but at least the outer 20% have conciderable coma. For a premium eyepiece, this is honestly the worst I have seen especially considering that the two APOs that I was using are relatively slow.
I did save the best and that is the absolutely amazing eye relief paired with the phenomenal adjustable eyecup design. The eye relief on all of these is very long. Normally that can actually be a bad thing as eye placement can be difficult resulting in blackout. With the Pentax, they do include a height-adjustable eyecup by simply turning the entire body of the eyepiece. The entire body rises slowly(it does take quite a few turns to get it to where you want it, but you really only do this once). I found that I was able to perfectly match the volcano-style eyecup to my viewing preference and it was VERY comfortable to use! This is honestly the absolutely best eyecup design I have ever tried(if you read any of my other reviews I usually don’t like eyecups at all)!
So at the end of the day is the Pentax XW’s for you??? I think that if you have a very slow scope you will be quite happy with them. In faster scopes(faster than f/8) I would say that the coma is just too much for the premium price! I do really miss the absolutely phenomenal adjustable eyecup design though!
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