TONTA Lens2Scope

Concept: 2 out of 5
Execution: 4 out of 5
Yeah, but: I docked a 'concept' point for the name.

Counter Opinion: I was intrigued from the moment I saw the remarkably functionally-named Lens2Scope, made by TONTA Electro Optical Co of Taiwan. Tonta also makes full spotting scopes, but the 'lens to scope' is just an eyepiece that attaches to various makes of lens – a different version for each mount – to make it easy for humans to look through them. It has pretty good eye relief and a prism to turn the image right-side-up, while focusing is handled by the lens. The Nikon-fit model that I tried is perfectly happy with both G and DX lenses.

A name that includes a cutesy numeral on something made of plastic always screams 'fly-by-night cheap' to me, so I was initially rather unimpressed and put off by the Lens2scope's $200 price. But using it with a Nikon 85/1.8D immediately and completely changed my opinion: the view was bright and crisp with a huge image circle. Of course camera lenses have excellent optics, and the Lens2Scope is only using a small part of the image circle, so perhaps I shouldn't have been so surprised at how good it was.

The way the numbers work with the Lens2Scope is to divide the focal length of the attached lens by 10 to determine its effective magnification, making my 85mm lens into an 8.5x power scope. The effective objective lens diameter is the physical aperture of the lens: remember that the "f" in "f/1.8" stands for focal length, so my 85/1.8 is essentially an 8.5x47 monocular. That rivals much bigger binoculars for both magnification and light-gathering, making the Lens2scope and 85mm quite compact by comparison.

The eyepiece also works with zoom lenses, and trying it with the 18-300mm was a lot of fun. Of course a darker lens means a darker image, and the higher the magnification – excuse me, the longer the focal length – the tighter the field of view. So a consumer zoom is functional and effective, while an f/2.8 zoom is very good. When coupled to a macro lens the scope adapter reportedly gives a 25x magnification at the lenses' 1:1 distance, which is not too shabby either. I can't say what the depth of field will be like, not having tried it, but I suspect that the Lens2Scope's little tripod mount could come in handy.

So the lens2scope definitely works. The next question has to be: for what? Anyone with a lens to attach it to probably already owns a compatible camera, and just looking through a lens is an odd thing for a photographer to do. But photographers have more than their fair share of odd behaviours, so I'm sure there will be people out there who would like to be able to turn a lens into a scope. People like me, for example.

I already own a small Zeiss 6x18 scope that I use to view prints presented to the critique group that I belong to – that's something like a camera club, but for photographers. So I actually know exactly where and how I'd use one of these lens toys. I'm eager to try it with my 60/2.8G lens, which becomes a 6x21, albeit a much bulkier combination than the little Zeiss 6x18. But the truth is that a 6x power can be a bit long for where I sit, making my 50/1.4G – 5x35 – a very, very interesting option. I'm pretty much sold on buying a Lens2scope even before I break out my old manual focus 135/2.8, which was an impulse buy against the possibility that it might be fun to have some day. It's nifty when things all work out like that.

Counter Opinions are quick "sales counter" product reviews.
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Last updated 28 july 2012