Pentax 65-EDA Scope

Tiger Shrike
14 Apr 2026 | Birdwatchers Society | Author : Arijit Banerjee
Large gear, even if qualitatively good, comes at a price, both in terms of money and weight. With airline baggage limitations becoming more and more restrictive, a frequent question asked about spotting scopes is about the utility of smaller scopes.
The smallest optics that theoretically fit in this genre are monoculars. They have their uses but are actually pocketable. They have some serious limitations too. Monoculars are a discussion for another day. In this instance, we shall restrict ourselves to the smaller scopes, the discussion revolving around the Pentax 65mm EDA scope (angled). The scope is also available as a straight scope (the model name changes to 65 mm ED). The best objective glass (spotting scopes vary in objective size 77mm, 80mm, 85mm and 100mm) helps to create an aberration minimised, sharp and contrasty image inside the scope. The prism assembly inverts an inverted image to make it erect. So how do you see it? Bare eyes… well if you can take your eyes near the prism; a magnifying glass - a possibility. It is the eyepiece that makes the view. The width of field and overall image quality including sharpness and brightness are functions of the eyepiece. Most spotting scope manufacturers make their own eyepieces. A sensible step is to have proprietary eyepieces otherwise they would lose money. Usually a zoom eyepiece is offered - 20x-60x odd magnification. Note here the same eyepiece will offer a lower magnification on a smaller scope. Using a zoom eyepiece you spot the subject and then zoom in to see its details. As you zoom in (in most cases the zoom mechanism is a part of the eyepiece) the image becomes bigger, the field darker or let’s say less bright and narrower. Often spotting scopes are not totally parfocal and need minor focus adjustments. The focusing mechanism is usually on the scope barrel - either as a large ring (or two separate rings for coarse and fine adjustments) or a small focusing knob on the barrel.

Made in Japan, the build quality and fit and finish of the scope is very good. Metal alloy tube covered by a nice armour. At barely 1070 gms it is lightweight. It is 270mm long, 115 mm high and 85 mm wide. Imagine a 390mm f6.0 lens. The tripod collar is solid and rotates with click stops. The front element is a triplet (3 lenses) – one of which is ED glass. In the middle is a fused doublet. This lens group is what moves to achieve focus. Towards the eyepiece side are two prisms. A built-in sliding lens hood/ dew shield helps a lot. Like it’s bigger cousins, the 80 and 100mm scopes, this one also has a 1.25” astronomy mount. The minimum focusing distance is 5 metres. The 1.25 inch (31.7mm) mount opens up a huge variety of eyepieces to chose from. The Pentax XW series eyepieces however are great. But do you want to mount a 550 gm XW 8-24 Zoom eyepiece on this lightweight scope?

There are many other options. Simple Plossl eyepieces and ones with more complex construction are available on the web, and they all can serve the purpose. There are very good eyepieces (and less expensive) in 1.25 inch mount available. Televue and Vixen are very well regarded brands. Bader Hyperion – might have an infinity focus issue. Ask around or get someone to pick up one from abroad.

However, one should consider the XF series of eyepieces from Pentax. Lighter, simpler and cheaper. The XF series comes in 12mm (32.5X), 8.5mm (46X) and a 6.5-19.5 mm zoom (20-60X). The eye relief for the two fixed focal length XF eyepieces is 18mm while the XF 20x-60x zoom eyepiece eye relief ranges between 15mm at 20x and 11mm at 60x, resulting in less than desirable eye-relief for eyeglass wearers when using the zoom eyepiece. Personally, I would settle for a 12mm eyepiece and enjoy the view. 32.5X magnification is 4 times more than my 8X binoculars. On this scope, 20X - 30X magnification shall give the best/ most pleasurable view.
In case of the bigger, heavier and more expensive XW eyepieces – magnifications on the 65mm scope are – XW7 (55.5X), XW10 (39X), XW 14 (28X), XW20 (19.5X), XW8-25 (16X-48X)
As for the use of the fixed focal eyepieces, some folks might find them a bit inconvenient. However, when I needed to change eyepieces, the "slide and twist" design allows me to change eyepieces quite quickly without sacrificing the extremely high quality of image provided by the XW series eyepieces. And anyways, my binoculars do not zoom. I can actually live with a fixed focal length eyepiece.

Convenience come at a price. Cost-wise, two Pentax XW eyepieces (E.g. the 28x and 58x magnification combo) will set you back about the same amount as the scope itself. Alternatively, one can elect to use just one XW eyepiece for all applications, in which case I suggest using either the 38x (XW10) or the 28x (XW14) eyepiece. I will gravitate towards the 28X (XW14) – the 65mm objective will have some resolution limitation vis a vis a 80mm/ 100mm scope. .

One way forward would be to get the 65mm scope with a fixed eyepiece first. If you still feel the need, then get the XF zoom eyepiece later. (You always can borrow the XW 8-24 eyepiece from BWS). The Pentax XF 20x-60x zoom and other XF eyepieces while less expensive, still provide a very good image, (although not quite as good as the XW eyepieces). The image generated by the XF eyepieces is less bright, somewhat warmer in coloration and has ever so slightly more chromatic and spherical aberration. Yet, despite these minor drawbacks, the XF series eyepieces provide an image quality that will satisfy all but the most discriminating viewer.
Just one more thing. When deciding a scope do plan for an appropriate tripod. Secretary BWs had suggested a lightweight carbon fibre travel tripod that is excellent., However, ideally, with a scope, tripods with pan-tilt heads 9the ones used by videographers) offer the most convenience.
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