The TK-2D rangefinder teleconverter: a peculiar beast

Description

Teleconverters for Leica-mount rangefinder cameras are few and far between, so when I saw one I was intrigued and bought it. I rationalised the purchase by telling myself that it would be more convenient to carry than a bulky long-telephoto lens that would only be used once in a blue moon. The teleconverter was a Soviet-made TK-2D (Figure 1).

[Note added after writing this article. I’ve just bought a Komura Telemore95 2× teleconverter – I've appended a brief view of my impressions at the end of this page.]

Figure 1. The Soviet TK-2D teleconverter for Fed and Zorki cameras, made for the home market. (a) Side view with original case; (b) top view; (c) bottom view.

Finding information on this teleconverter was difficult – most sources simply say ‘very rare’. Anyway, I’ve managed to discover a little about it:

• It was designed for FED cameras, and manufactured in small quantities by Zavod Tochnovo Preboroctpoeneya (Precise Instrument Works) in Kharkov, Ukraine, probably in the 1970s.
• It is a ×2 teleconverter, resulting in a 2-stop loss in light transmission.
• Its dimensions are approx. 38 × 49 mm (length × diameter), and both mounts are Leica screw (LTM).
• The focusing is rangefinder coupled.
• There is an 8 × 19 mm (length × diameter) protrusion at the front, so only lenses with recessed rear elements can be used, i.e. telephoto and slow standard lenses.
• It was designed for use with the Soviet Jupiter-9 and Jupiter-11 telephoto lenses. Other lenses reported to work well with the TK-2D are the Industar-61 and slow Leica Elmars.
• It works best with lenses that have reasonably broad focusing rings instead of pawls. Lenses with pawls and very thin focusing rings may not engage properly with the TK-2D’s focusing mechanism.
• Marc Small (author of Non-Leitz Leica Thread-mount Lenses) describes it as ‘superb’, and says it ‘is much more finely made than the rather crude Komura and is a world ahead optically’. (Komura made the only other Leica-mount teleconverter for rangefinders, occasionally found selling for several hundred dollars second hand.)

I can add the following observations:

• It is very solidly built from machined aluminium.
• The lens elements are multicoated.
• The focusing mechanism is basic: a cylinder tensioned by a spring transmits the movement from the lens focusing ring to the camera; the cylinder ends in three tabs on which the lens focusing ring rests.

Performance

I’ve tested it briefly with my Cosina Voigtländer (CV) 75 mm f/2.5 lens and Epson R-D1. The TK-2D converts the lens to 150 mm f/5, and the R-D1’s APS-sized sensor increases the focal length further, to an effective 230 mm – pushing things somewhat for a rangefinder! I was pleasantly surprised by how well the teleconverter performed:

• it’s sharp and degrades the CV lens very little
• focusing is accurate, although tricky owing to the long focal length.

Figure 2 shows photos taken with and without the TK-2D on my CV 75 mm lens, with the latter resampled to 200% so that the images are identical in size. As can be seen, the TK-2D photo shows considerably more detail. The lower contrast of the TK-2D shot is partly due to flare (compare the shadowed areas on the lower balcony).

Figure 2. Photos of a balcony 150 m distant: (a) taken with the TK-2D on my CV 75 mm lens; (b) taken with the CV 75 mm lens only (resampled to 200% in Photoshop). Notes: (1) both photos have been processed identically, with equal amounts of sharpening; (2) the sun had gone in when I took the TK-2D shot, hence the colour difference.

There is one major downside – it flares horribly:

• Above a marked f/5.6 (= f/11), every shot shows veiling glare, which worsens drastically as the lens is stopped down (at f/22 it looks as if I’m shooting through tissue paper!).
• At a marked f/4 (= f/8) and wider, the flare disappears, and shots are sharp with good contrast.
• Situations that don’t affect my other lenses (e.g. the sun in front of the camera but high in the sky) also cause flare, at all apertures.

I’m not sure why the flare’s so bad. It’d be interesting to see if it occurs with other lenses, especially the Soviet ones for which it was designed (it won’t fit my other lenses). I found no mention of flare when I was looking for information on the TK-2D, which is surprising considering how significant it is. I wonder if the TK-2D and the CV 75 mm are simply a poor match …

The Komura Telemore95 2× teleconverter

I’ve now bought the other Leica M teleconverter. Here are my initial impressions. I should mention that my equipment has changed: I have sold my Epson R-D1 and now use a Leica M8, and the CV 75 mm lens has been replaced by a CV 90 mm lens.

The Komura teleconverter was sold in the 1970s to 1980s in a natty case with an accessory zoom viewfinder (80–270 mm) and a screw-to-M-mount adapter that brings up the 90 mm framelines. These teleconverters are reasonably common but have a poor reputation: I was interested to see if this was justified.

The finish and production are average: the machining is not up to Leica standards, and the lens mount (at the "front") is a little stiff. I’ve heard that the finder, which I don't have, is poor optically but usable. On the plus side, the design is well thought out: the rear mount is Leica screw and the front Leica M, which means that it can be used with any combination of Leica M and screw mount cameras and lenses with the aid of mount adapters (one was supplied with the teleconverter).

I didn’t have high hopes for it optically, judging from its reputation. However, I was pleasantly suprised: focusing was spot on even at 1 m, and the photos were surprisingly sharp. The ideal aperture for the CV 90 mm–teleconverter combination is f/5.6 – images start to blur at f/8 and smaller. The CV 90 mm lens is susceptible to veiling flare, and this is much more apparent when the teleconverter is used, so the lens needs to be well shielded and conditions producing flare avoided. Conveniently, the field of view is easy to estimate on the Leica M8: the edges fall exactly halfway between the 90 mm framelines and the finder patch. Focusing on close subjects minimises flare, and the teleconverter would make a handy accessory for close-ups , which are difficult to take with a Leica rangefinder.

In conclusion, I don’t think the converter is as bad as people have made out, at least when used with the Leica M8, and it works better than the Soviet one. It’s a useful addition to my armoury: firstly for close-up shots of details and small objects, secondly for those occasions when I don’t want the inconvenience of carrying a long lens and thirdly for when I need the reach of a very long lens (on the Leica M8, a 90 mm lens has an effective focal length of 230 mm, and a 135 mm lens, 350 mm).