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05-11-2008, 03:23 AM - 1 Like   #1
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Vivitar 2x Macro Focusing Tele Converter: definitive thread

I've recently obtained a Vivitar 2x Macro Focusing Tele Converter, known as the V2XMFTC for short. It is remarkably difficult finding hard info on this device, so I thought I'd gather some here and solicit updates from the rest of you. The results I'll put together in a "definitive" article.

The V2XMFTC uses a combination of optics (a multi-coated 7-element configuration) plus an extension tube to double the focal length of any lens attached to it. It's solid metal and heavier than you'd expect. Though with caps the unit is 6cm tall, the working portion is only half that, about 30mm. The rest of the device is taken up with the K-mounts.

The magnification ratio achieved for an extension tube is calculated as extension length / lens focal length. According to the dual-coloured ring markings on the V2XMFTC a 50mm lens results in a maximum of 1:1 magnification at a minimum distance of 45cm. Apparently, then, this device works as though it was an extension tube of length 50mm. The effective aperture will then be double the set aperture number. For example, f/1.4 becomes f/2.8, or a 2 stop loss in light.

In short, the V2XMFTC converts a 50mm f/1.4 lens into a 100mm f/2.8 1:1 macro.

There are two distinct versions of the V2XMFTC. Contrary to some rumors, you cannot tell the difference based on the colour of the ring markings. Both types can be found with either blue or green numbers. Instead, look to the text before "JAPAN". If it says "P/K" it lacks the coupling pins for aperture info. If it says "P/K-A R-P/K" lenses attached may be operated in "A" mode. In either case you must focus manually.

Supposedly the same device is available with the brand names Panagor, Albinar and Lester Dine, but not in the "A" configuration. All were manufactured by Kiron.

Working as a 2x teleconverter, the V2XMFTC has all the problems of such devices. It accentuates any flaws in the lens and introduces some of its own. For one you will get wicked purple fringing and chromatic aberration in any back-lit shot. The consensus is that 2x is too much magnification to expect of a teleconverter. It is better to stick to 1.4x if you require good image quality. Or use 1.7x only in the case of the Pentax-F 1.7X AF Adapter, which goes for big money as a result.

However the advantage of the V2XMFTC is in its macro focusing. It converts any lens to a macro lens, and might be handier than carrying two separate lenses. Jens Roesner compares the Vivi plus Pentax A 50mm 1.4 favorably to the D-FA 100mm 2.8 Macro on this informative page.

I decided to do some testing of my own, using three lenses I happen to like, the FA43mm, FA77mm and Cosina 100mm. I'll post some results once you've pointed out any errors in what I've written so far.

05-11-2008, 03:26 AM   #2
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Here is the review thread.
05-11-2008, 04:52 AM   #3
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Thanks very much for posting this information.
Respectfully,
Stu in Michigan
05-11-2008, 05:09 AM   #4
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And if you mount a 50mm backwards with a reversing ring on it it'll go better than 1:1. Best to use a MF lens and stop down meter though.

05-11-2008, 05:17 AM   #5
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This is just a little extra info, but I put my Lester A. Dine 105mm macro lens on mine, and with that lens focused to 1:1 and the teleconverter at its closest focus setting the magnification is about 2.6:1.
05-11-2008, 05:29 AM   #6
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Good idea for a thread. I own 2 of these PK/A versions and they work well. I never use them as 2x units for the reasons above. I've used it with the FA50/1.4 with very good results and sometimes with the FA50/2.8 macro but that gets very close and with less workable results (DOF). I'll take a few shots today as well and post the results.

I can't add much to the tech end of the thread. Looks like you have most of it covered. Here's the review in our database with a picture.

PentaxForums.com Third-Party Pentax Lens Review Database - 2X Macro-Focusing Teleconvertor
05-11-2008, 05:41 AM   #7
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QuoteOriginally posted by Peter Zack Quote
I own 2 of these PK/A versions and they work well. I never use them as 2x units for the reasons above.
You can't not use it as a 2X teleconverter unless you have taken the glass out of it.
05-11-2008, 05:54 AM   #8
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QuoteOriginally posted by clm Quote
You can't not use it as a 2X teleconverter unless you have taken the glass out of it.
Not so. Maybe you thought I was using 2 together. No they are used independently (one is in my son's kit). You don't have to remove the glass for it to be a 2x unit. Just turn th focus helicoid to the retracted position. Then it's a normal 2x converter. It is only a macro converter when the helicoid is extended.

05-11-2008, 05:57 AM   #9
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This vivitar 2xTC is rather hard to find. Would a Kenko SHQ 1.5X TC work sufficiently well with the FA50 for macro purposes? It is not a 100mm f2.8 but a 75mm f2.8. Is it too short?
05-11-2008, 05:58 AM   #10
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I got one of these from Heather a while ago but haven't used it much yet - look forward to your results. I also have a Panagor 'Macronet' which is 3X and 1.5:1. The mechanism is internal so no 'telescoping', and it is manual (no 'A' setting). Works very well with the 1.4s and 1.7s...............
05-11-2008, 06:33 AM   #11
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QuoteOriginally posted by Peter Zack Quote
Not so. Maybe you thought I was using 2 together. No they are used independently (one is in my son's kit). You don't have to remove the glass for it to be a 2x unit. Just turn th focus helicoid to the retracted position. Then it's a normal 2x converter. It is only a macro converter when the helicoid is extended.
You said you never use them as 2X units.
I said you cannot NOT use it as a 2X. I know how they work, I have had four of them in three different versions.

My point is that if you put one on a camera with a lens, it always multiplies the focal length of the lens by 2.
05-11-2008, 07:02 AM   #12
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QuoteOriginally posted by clm Quote
I said you cannot NOT use it as a 2X. My point is that if you put one on a camera with a lens, it always multiplies the focal length of the lens by 2.
I don't want to get in an argument here but unless I'm somehow way off base, Isn't putting the Vivitar unit on first (without extending the helicoid) , then mounting a lens on using it as a 2x? So for example a 50mm/1.4 becomes a 100mm/2.8 which is a 2x conversion.

If I'm wrong, please correct the above.
05-11-2008, 07:11 AM   #13
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That is correct and that is what I am pointing out, but in your first post you said you never use it as a 2X. Read my first post carefully. I said "can't not," meaning you don't have a choice in whether you use it as a 2X or not, because that is what it is, regardless of whether the helicoid is extended or not.

Last edited by clm; 05-11-2008 at 07:23 AM. Reason: added comment
05-11-2008, 07:14 AM   #14
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There is also a Ricoh version.
05-11-2008, 08:00 AM   #15
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I'm sorry. Yes you are indeed correct, it is always a multiplier. I simply meant I don't attach a 300mm or similar to get 600mm 'prime' and shoot that way. There are CA and PF issues with this unit and it does degrade the IQ as well. In fact it don;t know of any 2x units that don't cause IQ problems with possibly the exception of the matched Tamron adaptall 2x's with lenses like the 90mm/2.5 macro.
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