Kowa Prominar TSN-99A


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£3,449 (with TE-11WZII zoom eyepiece)

Reviewed by Matt Merritt

A 99mm objective lens makes for a bright image ©Kowa

In the world of scopes, bigger is increasingly being seen as better. We’ve seen objective lenses shatter the 100mm diameter barrier, and now Kowa have come up with a super-sized addition to their much-loved Prominar range of scopes.

With a 99mm objective lens, it’s big. Not, at first sight, necessarily a great deal bigger than its 88mm predecessor, but with that much glass, you’re going to feel the extra weight. That said, you knew that anyway.

Elsewhere on this website, we take a look at what happened when we got a beginner to test it, as well as a diehard Kowa user, and we’ll put it through its paces with a phone-scope adapter. But to start with, I tested it with the zoom eyepiece mentioned above (30x-70x magnification), as well as the TE-80XW wide angle eyepiece, in a variety of birding situations.

TE-11WZII zoom eyepiece
The image produced is very bright, and very sharp right to the edges, with excellent contrast and very natural colour.

A zoom eyepiece allows up to 70x magnification ©Kowa

That was entirely predictable, I suppose, on a bright morning, but the eyepiece really showed its quality on a murky, drizzly evening, scanning some distant waders on a gravel pit.

That huge objective lens still creates a very bright image, and even zoomed right in to 70x, it was sharp and didn’t feel restrictive. At that magnification, of course, you do notice every little wobble, but it still felt far more usable than maximum magnification on many scope/eyepiece set-ups. Colour-fringing was near impossible to find at any time, even against very strong light.

The eyepiece itself twists up and down to four positions, and it’s comfortable in extended use, offering a maximum of 17mm eye relief.

TE-80XW wide angle eyepiece
I’m a big fan of fixed magnification eyepieces, on the grounds that I rarely use a zoom at much higher than 30x anyway.

The TSN-99 refines the Prominar’s classic design ©Kowa

This, it has to be said though, is something else. Wide angle hardly does it justice, because the view feels incredibly ‘walk-in’, so expansive is it, and the image is sharp, with totally natural colour, and no colour-fringing. Magnification is 40x, too, with the TSN-99, so you have all the punch you need for most situations.

I did find it very slightly harder to find precise focus than with the zoom, but I can’t really see any reason why that should be, so perhaps it was just fatigue setting in on my part.

Main scope
The build is excellent, and very much along the lines of the existing Prominar scopes. There are two focus wheels, mounted centrally above the barrel, with the main one being a finger and a half wide, and the fine focus wheel just over a finger wide. They’re well ridged and easy to use even with gloves on, but if I’m being picky I’d like just a little more separation between the two.

You will need a sturdy tripod to get the best from the scope ©Tom Bailey

The wheels move very smoothly and moderately stiffly, with the main one taking two clockwise turns from close focus to infinity. Close focus, by the way, is 6m, but that’s not really what you’re buying this scope for.

So, what about the size? Well, you do need to make sure you have a good, very solid tripod, ideally with a large baseplate, to ensure that there’s not too much shaking and wobbling when you’re viewing, and you may well decide that you need some sort of scope harness or pack, too, because carrying the TSN-99A around for a day certainly tests your arm muscles. But, and it’s a big but, I don’t think you’d notice if you’re already a user of the 88mm Prominar, or any similarly sized scope.

The lens hood also includes a useful sighting device ©Kowa

Verdict
This is an exceptional scope, used with either of the reviewed eyepieces. It is, inevitably, reasonably heavy, but that shouldn’t put you off at all if you set yourself up properly.

Rating (out of 5)
Optics 5
Design 4½
Value 4½
Overall 4½

Specs
Length: 378mm
Weight: 1,810g
Field of view: 39m@1,000m (WA eyepiece)
Close focus: 6m
Eye relief: 17mm (both eyepieces)
Website: kowaoptic.com

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