Has anyone used the German single-element teleconverters

Made by JSCO, the ones I saw are 42mm push-on, which fits my 150mm Zeiss Jena Tessar f/4.5. I use this lens on 6x9.

One of them is a 1.4x teleconverter, the other is a 0.8x teleconverter, which would change the lens to 210mm and 120mm, respectively.

I'm not looking for optical perfection from these - but is the character they add to the image pleasing? For portraits or isolated central subject photography. Does it make something of a soft focus effect?

The names are
Veriangerungslinse 300/420 B
Verkurzungslinse 20/420 E

If you want to introduce more chromatic aberrations and in case of 0.8x reducer the distortion at the edges and corners, then this is the option for you.

The first one 1.4X is a negative diopter INCREASING the apparent FL, while the other 0.8X is a positive diopter SHORTENING the FL.

The first turns a 150mm lens into a 210mm lens (additional bellows needed), while the other creates a 120mm lens (less bellows needed).

That's roughly equivalent to +/- 1.5 diopters -- not very strong. Results should be fine stopped down. Wide open they would be great for portraits, softer effects.

Thanks. I can't find any example pictures anywhere online with these so I guess I'll have to post the first!

loccdor said:

Thanks. I can't find any example pictures anywhere online with these so I guess I'll have to post the first!

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Hi,
I'd like to see pictures with the Verlängerungslinse (aka Distar if made by Zeiss...).
The Verkürzungslinse (aka Proxar) should work fine with a Tessar.
I use such for my Rolleiflexes - here the Proxar 1 works very well, the Proxar 2 (reduces fl to 0.9x) is good with less contrast and sharpness and a swirly bokeh.
Jens

lobitar said:

in contre-jour situations the ubiquitous inner reflections in the Tessar practically disappears!

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Quite interesting!

JensH said:

I'd like to see pictures with the Verlängerungslinse

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I'll must remember to post them here when I try them out. Since I'm using 6x9 on a 4x5 lens there will probably be less edge sharpness loss but I don't know yet.