dan_fromm2 Posted March 26, 2016 Share Posted March 26, 2016 <p>JDM, as long as you're in an accumulating frame of mind you should try to get one of these: https://www.cameraquest.com/viv45045.htm. To get back on this thread's topic, try to find the matched multiplier (2x TC) that goes with it. T-mount lens, T-mount TC.</p> <p>I have the TC, not the lens. It isn't all that wonderful on my Questar 700, but at 1400 mm the problem may be unsteadiness more than optical performace.</p> Link to comment Share on other sites More sharing options...
JDMvW Posted March 26, 2016 Author Share Posted March 26, 2016 <p>Unfortunately, I seem to always be in an "accumulating frame of mind". :|</p> <p>At the end of the article on the Vivitar 450mm f4.5 (<a href="https://www.cameraquest.com/viv45045.htm">link</a>) it says:</p> <blockquote> <p><strong>Unfortunately Vivitar's once great lens designs are pretty much a mystery to today's Vivitar. Repeated emails and phone calls on company history are usually unreturned. Occasionally I was told "we don't have those records." Sad, for a once leading Photo Optical Company not to have a clue about itself.</strong></p> </blockquote> <p>The reason for this is that only the NAME of the company was purchased by the <em>new owners</em> - nothing else. They apparently just wanted to exploit what was once a recognized and honored brand.</p> Link to comment Share on other sites More sharing options...
Mike Gammill Posted March 28, 2016 Share Posted March 28, 2016 <p>Correct me if I’m wrong but I believe the teleconverter can trace its origins back to Peter Barlow, a mathematician and physicist developed such a lens for telescopes during the 1800’s. In general Barlow lenses are not as well corrected as teleconverters, but only have to work over a limited field of view. Although originally intended for visual use, some Barlow lenses have T-threads for attaching photographic T-rings. Edmund Scientific used to sell unmounted Barlow elements so one could custom design one’s own system to multiply focal length.<br> Sorry, JDM, I hope I didn't hijack your thread.</p> Link to comment Share on other sites More sharing options...
JDMvW Posted March 29, 2016 Author Share Posted March 29, 2016 <blockquote> <p>Way back in 1959, a few people had <strong><em>re-discovered</em></strong> that in addition to close-up plus-lenses, there were also minus-lenses. [emphasis, JDM]</p> </blockquote> <p>Of course in the broader sense, the teleconverter <em>is</em> a form of Barlow lens, which is and was a combination of minus lenses, etc. However, I still think that the modern history of the camera lens teleconverter, as such, is as outlined above.</p> Link to comment Share on other sites More sharing options...
JDMvW Posted May 16, 2017 Author Share Posted May 16, 2017 An addition to the post, will both re-animate this post and provide a tiny bit more background for the early days. First, the original article had a pdf from Modern Photography 1959-11 these are jpgs of that article and some additional bits: Link to comment Share on other sites More sharing options...
JDMvW Posted May 16, 2017 Author Share Posted May 16, 2017 (edited) Also, here is a query from a letters column in the same issue, which was not presented before: Edited May 16, 2017 by JDMvW Link to comment Share on other sites More sharing options...
JDMvW Posted September 1, 2017 Author Share Posted September 1, 2017 And yet another REANIMATED discussion, this one from Popular Photography 1976-10 Link to comment Share on other sites More sharing options...
Mike Gammill Posted September 2, 2017 Share Posted September 2, 2017 Anything on early teleconverters or use of negative lenses to increase focal length is always interesting. Thanks for sharing. Link to comment Share on other sites More sharing options...
JDMvW Posted May 22, 2018 Author Share Posted May 22, 2018 As Dr. Frankenextender, I hereby re-animate this old thread by adding another bit of "prehistory" to the history above. It was part of a Spiratone ad in Modern Phitography 1955-03 Link to comment Share on other sites More sharing options...
john_robison4 Posted May 23, 2018 Share Posted May 23, 2018 (edited) I've got that little Duo-Tamron shown in the ad and listed as "famous make" 135mm f4.5 tele that has a little 1.66X included. It was introduced in 1958, don't know how long it was sold. It is not a "T" mount but about 37mm or so. Mine came with a M42 adapter otherwise you would never find adapters for it. The front filter thread is also a very strange size, somewhere between 38 and 39mm. It came with an adapter for series 6 but that was gone from my sample. The teleconverter has a single element, or more likely a cemented doublet. When attached it is a tiny package for a 225mm lens, but of course that is at f7.7 maximum aperture and that makes for a fairly dim viewfinder. With the teleconverter attached it is 107mm long and 8.5oz or 245gm. Edited May 23, 2018 by john_robison|4 Link to comment Share on other sites More sharing options...
rick_drawbridge Posted May 24, 2018 Share Posted May 24, 2018 A pic for those who have never seen a Duo-Tamron. There's a bit of information here: Small but Significant : The Duo Tamron It has a bigger brother in the Tamron 135mm f/2.8 Twin-Tele (AKA Converto-Tamron) Duo Tamron Link to comment Share on other sites More sharing options...
fmueller Posted May 27, 2018 Share Posted May 27, 2018 Great writeup, JDM! As soon as I saw this, I was going to post about the 2x Vivitar macro teleconverter, but others have beaten me to it! That thing really was a fantastic device, combining a 2x teleconverter with a variable extension tube. I had one not branded Vivitar, but almost certain to have come from the same factory, for the Minolta MD system. I mostly used it with an MD 50mm 1.4, which turned this lens into a 100mm macro lens that could go down to 1:1 without the need to fidget around with extension tubes. The quality might not have been quite that of a genuine 100mm macro lens, but close enough for me - and at a fraction of the cost! Link to comment Share on other sites More sharing options...
Mike Gammill Posted May 28, 2018 Share Posted May 28, 2018 A couple of years back in thread I mentioned the Soligor Multipurpose Teleconverter. I found some images of it. Again, the 2x element (4 elements) can be removed to allow it to serve as an automatic extension tube. Teleconverter by camera with converter elements removed Link to comment Share on other sites More sharing options...
davecaz Posted May 28, 2018 Share Posted May 28, 2018 A couple of years back in thread I mentioned the Soligor Multipurpose Teleconverter. I found some images of it. Again, the 2x element (4 elements) can be removed to allow it to serve as an automatic extension tube. [ATTACH=full]1247564[/ATTACH] Teleconverter by camera [ATTACH=full]1247565[/ATTACH] with converter elements removed Well, that's an interesting design! Never seen anything like it. Link to comment Share on other sites More sharing options...
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