I bought this as a low power eyepiece for my Mewlon 180C, and indeed the full moon fit comfortably in the field of view despite the scope's long foca length. The image quality seems on par with the other Pentax XW eyepieces, and I did not notice any field curvature, perhaps due to the scope's long focal length or slow focal ratio.

I have only ever owned Baader Hyperions before. I splurged on this Pentax 40R. OMG, it was like I don't know what I was looking through before because if this is what an Eyepiece should be, then whatever I was using in the past was simply sub-par. And that is saying a lot because the Baader Hyperion is considered an excellent eyepiece set. This was twice as bright. Twice as natural. The field of view was vast and clear through to the edge. Eye Relief is amazingly good. My only complaint is the crappy little lens cap which doesn't seat well into the click-up eye cup. With that much design sense going into the lenses, you'd think they could do something better with the simple plastic lens cap. Oh well, small price to pay to look through this every day. It is my default now.

Delivered today with an XW 30. Both longed-for at a reasonable price. Thsnk you FLO for shipping out so fast!

The XW 40-R has "Made in Japan" sticker. Its instruction leaflet is in Japanese. The box as for all XWs & the XL SMC zoom is silver. "Ricoh" and "Pentax Accessories" in black on the lid.

The eyepiece is inside a well padded bolt case, in the box, again as for all XWs.

Its eyecup twists with buttery smooth exactness to raise and lower eye distance. As I wear glasses, even when viewing only a slight twist up but, very exact, was needed.

Eye relief and comfort are luxurious. No "kidney beaning" (spherical aberration of the exit pupil) was present. The same applies for my XW30.