An Odd Little Thing

Every now and then I come across some photographic accessory that I've never come across before. This Sigma Telemac Vario 2x Auto Converter is in this category.

 

Sigma Telemac

 

 

Basically, it seems to be a teleconverter, in this instance in M42 mount, that enables variable conversion ratios from 2x to 3x. It has a base unit with several elements, the rear element moving in a helicoid between stages marked 2x, 2.5x and 3x. Two extension rings are supplied, one marked 2.5x and the other 3x. In practice, if one requires 2x multiplication of focal length you mount the lens on one end of the converter and attach the other end to the camera, with the helicoid set to 2x. If you want 2.5x, you remove the converter from the camera, add the ring with the 2.5x marking and reattach, lining up the 2.5 index mark. It's the same procedure for 3x, first removing the 2.5x ring and replacing it with the 3x.

 

Here's a pic of the thing attached to a camera with the 3x ring fitted, with the 3x mark on the teleconverter unit revolved to match the index mark on the ring.

Mounted

 

 

I've not come across a teleconverter of this design before; it seems to be rather rare, though I'm sure there must be other similar ones out there. I tested it on a Sony full-frame camera using a 35mm Super-Takumar f/2.8 lens, fully expecting a dire loss of image quality, but was quite pleasantly surprised. There was a very slight loss of sharpness, but none of the dreadful CA's small teleconverters usually produce. Here are two images, the first one full-frame with the 3x ring fitted, and the second a crop from the centre of the image.

 

Full Frame

 

 

Crop

 

 

If anyone out there is acquainted with this or other similar teleconverters, please add your comments.

 

 

 

 

 

 

 

 

 

 

 

 

 

Very interesting, Rick. Never heard of it before.

 

I do have a Kiev 2x teleconverter in Nikon mount, which has a removable optical block, allowing you to use the body as an extension tube.

 

Gee, Rick - that looks familiar!

Gee, Rick - that looks familiar!

 

Ah, 'tis a small world...Did you ever use it, John?

m42dave said :

I do have a Kiev 2x teleconverter in Nikon mount, which has a removable optical block, allowing you to use the body as an extension tube.

 

So that's what they look like, Dave. I've read about them but never seen one in the flesh, so to speak.

Ah, 'tis a small world...Did you ever use it, John?

No, Rick - I don't even remember where I got it. My experience of teleconverters has not been good, and I have M42 lenses to cover the focal lengths I use.

The Kiev reminds me of the Soligor multipurpose 2x converter. Ordinary 4 element converter and optics bayonet out to allow function as automatic extension tube. Still have it today.

One of the best optical quality teleconverters I've ever used is the Vivitar tele-macro. This has a built-in helicoid that allows closer focussing than the lens fitted to it normally allows. With most 50mm lenses it'll allow focussing to lifesize.

 

However, in some fittings its construction leaves a lot to be desired. In Nikon Ai fitting, for example, the plastic coupler ring is unstable and expands over time to the point where it jams in its mounting.

This is a bit off subject, but I bought what I thought would be good quality add-ons to the Nikon L35AF. Included were a tele and wide attachment. Seeing as the base equipment was Nikon, I thought the accompanying glass would be a lot better than it was ... the results were IMHO awful....

In fairness, the price was quite the bargain too. Bottom feeders... deserve indigestion I guess...

The tele and wide attachments are simple Galilean telescopes. The better ones will have enough elements to give some resemblance to a sharp image, but magnifications are understandably low otherwise the elements would have to be very large to cover the format. I think the best in front of lens converters I've seen are the ones that go with the Olympus IS series ZLR cameras. Still wouldn't go out of my way to find one for my IS-30, though.

rodeo_joe|1 said :

One of the best optical quality teleconverters I've ever used is the Vivitar tele-macro

 

Is that the same as the converter in the pic below? The only teleconverters I've had much luck with have been the Tamron Adaptall II SP Flat Field converters.

 

Vivitar 2x Macro Focusing Teleconverter (FD Mount)

 

Edited August 25, 2018 by rick_drawbridge

I was once told that Kenko made the Tamron TCs. They might be a little lower price if they say Kenko on them.

During the peak of film photography (especially before AF) these close focusing teleconverters and similar attachments could often be a good, but less expensive alternative to a true macro lens unless one needed a flat field and edge to edge sharpness. With it being a "buyers market" for many previously pricey true macro lenses I probably wouldn't buy any of these accessories today except just for fun and only if super cheap.

My first true macro lens was a 50mm f 3.5 Rokkor QF preset that I bought for 10 USD in the mid 1980's. Before then my Soligor Multipurpose 2X converter with either 50mm or 100mm lens served me well,

Here's an old post of mine that is sort-of related

In Search of Reach: Tele Converters

 

 

You may be interested in how well some of these work with lenses like the Reflex-Nikkor 500mm

I was once told that Kenko made the Tamron TCs. They might be a little lower price if they say Kenko on them.

That seems unlikely, because Kenko is the US importer of Tokina lenses. Seems like a conflict of interest.

This one:

 

Third party teleconverters vs Nikon

 

claims that they are, and is more recent than when I thought I knew about them.

 

But maybe someone else knows more than I do.