Pentax Orthoscopic 5mm

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Brand and Model:Pentax Orthoscopic 5mm
Price ($USD):Discontinued
Focal Length:5 mm
Barrel Size:0.965 in
Apparent FOV:42.0 degrees
Field Stop Dia.:0.0 mm
Eye Relief:0 mm
Weight (lbs):

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Pentax Orthoscopic 5mm
Picked this up last fall and then had one of the worst observing winters so this mostly just sat in my accessory kit until this spring. The skies just couldn't take this much magnification. I even started to wonder if I made the right move. I paid more for this ocular than any of the others and I was hardly using it!

But the skies finally cooperated this spring and WOW, it was worth the wait, (and expense)! Unlike the other person, I find this eyepiece every bit as good as the others in the series. Minimal ghosting, ultra-sharp, right up to the fieldstop, excellent light throughput, and even rather comfortable due to it's small profile. I take my glasses off at the eyepiece and can easily take in the entire 42deg AFOV.

These have been out of production for quite some time now. Perhaps the other reviewer picked up a used one that wasn't cared for properly. My first 7mm Pentax ortho I bought wasn't up to par so sold it. The second one matches the excellence of the others in my set. So maybe they picked up a sub-par 5mm. Fortunately mine was well cared for.

Any of these Pentax orthos are a true joy to use.

Overall Rating: 10
Optics:10 Value:9
Weight: 20 (Notable Vote)
By: msuther
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Pentax Orthoscopic 5mm
This is the shortest focal length in the famous Pentax smc orthos. The superior coatings on this ocular really keep down stray light and ghosting. The 5mm is not quite as sharp as the 6mm, some have speculated the design is a compromise between eye relief and performance. None the less, it is superb as a planetary eyepiece! Also the rarest of the smc series orthos on the used market.

Overall Rating: 10
Weight: 1 (Unreliable Vote)
By: Anonymous (
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