I've just bought a Soviet TK-2D teleconverter on Ebay for my Epson R-D1 because (a) I was intrigued and (b) it's more convenient to carry than a bulky long-telephoto lens that would only be used once in a blue moon.
Finding info on this teleconverter was difficult - most sources simply say "very rare". Anyway, before buying it I managed to discover a little about it, and after the effort I expended, I thought I may as well post my findings here in case anyone else is interested!
This is what I found on the web:
- It was designed for FED cameras, and manufactured by "Zavod Tochnovo Preboroctpoeneya" ("Precise Instrument Works") in Kharkov, Ukraine.
- It is a x2 teleconverter, resulting in a 2-stop loss in light transmission.
- Its dimensions are approx. 38 x 49 mm (length x diameter), and the the mounts are LTM.
- The focusing is rangefinder coupled.
- There is an 8 x 19 mm (length x diameter) protrusion at the front, so only lenses with recessed rear elements can be used, i.e. telephoto and slow standard lenses. Lenses reported to work well with the TK-2D are Jupiter-9, Jupiter-11, 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 on Ebay selling for several hundred dollars.)
I've tested it briefly with my 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-D1ís 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:
- Itís sharp and degrades the CV lens very little.
- Focusing is accurate, although tricky owing to the long focal length.
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 loo roll!) - which seems counter-intuitive to me.
- Below a marked f/4 (= f/8) the flare disappears, and shots are sharp with good contrast.
- Situations that donít affect my other lenses, e.g. the sun in front of the camera but high in the sky, also cause flare, at all apertures.
Iím not sure why the flareís so bad. Itíd be interesting to see if it occurs with other lenses, especially the Soviet ones for which it was designed (it wonít fit my other lenses). I found no mention of flare when I was looking for info on the TK-2D, which is suprising considering how significant it is. I wonder if the TK-2D and the CV 75 mm are simply a poor match ...
The first attachment shows the TK-2D. The second shows shots taken with (left) the TK-2D on my CV 75 mm lens (100% crop) and (right) the CV 75 mm lens only (resampled to 200% in Photoshop). Notes: the sun had gone in when I took the TK-2D shot, hence the colour difference; the lower contrast of the TK-2D shot is partly due to flare (compare the shadowed areas on the lower balcony).
If anyone else has used this teleconverter or has any thoughts on it, I'd be interested to hear them.