TEST Teleconverter 2x: Konica vs Minolta

[stevemark]

The Konica Hexanon Teleconverter AR 2x is a pretty rare piece of equipment introduced in the early 1980s for the Konica AR SLR system. The heydays of teleconverters were the early 1970s when cheap three lens [3L] converters from 3rd party manufacturers were sold widely (and inxpensively of course). Towards the mid-1970s Canon and Minolta had introduced some high performance converters specially designed for their FD 2.8/300mm Fluorite (Canon) and MD 5.6/400mm Fluorite (Minolta) lenses. Nikon would be following soon.

Around 1980 those specialized "long range" converters (300mm upwards) were supplemented by new "short range" converters for lenses in the 50mm to 200mm range. That was the moment when Konica introduced their first and only AR teleconverter, too. During this time Konica had lots of problems with unreliable electronic SLR bodies, and they were not the well respected company any more they had been in the 1965-1975 time frame. In addition around 1983 the 4/80-200mm telezooms really became popular, and thus the teleconverters (often combined with the ubiquituous 2.8/135mm lenses) became redundant. That explains the rarity of the Konica converter.

OK, here it is:


The Konica AR 2x converter is a pretty sophisticated [6/5] construction, and one would expect an appropriate performance.

I have compared the Konica AR 2x converter & AR 1.7/50mm lens with the Minolta MD 2x-S converter & MD 2/50mm lens.




The results are pretty surprising and may explain why the Konica 2x converter wasn't selling well.

OK, here's the center wide open (effective f4 for both combinations since they support only f2 apertures), at f8 (eff) and at f16 (eff):



The difference is clearly visible when the lenses are wide open. Stopped down to f4.0 (effective f8.0) the Minolta is tack sharp, the Konica not so much but still perfectly useable. At f8 (eff f16) both lenses suffer from diffraction.

But holy moly ... the corners ...!!!




Well, these are the corners. Minolta vs Konica, both with their best normal lenses on their original 2x converter.

I don't know what's going on here, but the results of the Konica converter are devastating. I don't think there's a problem with my specific sample of the Konica AR 2x converter, since it looks "like new" and was given to me together with its equally perfect lens quiver. BTW it's not just the corners that look bad on the Konica, but large parts of the image! Maybe the AR converter was designed specifically fro one of the Konica tele lenses (I'll check it tomorrow wih the 135mm and 200mm lenses), but it's certainly not usable in combination with the AR 1.7/50mm normal lens.

The Minolta 2x-S converter however really shines in combination with the MD-III 2/50mm lens. Slightly low contrast and some CAs wide open, but very good at f4.0 (eff f8.0), even in the corners, and nearly free from CAs. Well done Minolta!

S


EDIT: wrong descriptions on the test images corrected!

[stevemark]

A quick test comparing the two converters & their respective 3.5/135mm lenses (AR and MD-II both from around 1980) again results in much better images from the Minolta combo, although the results from the Konica combo aren't as bad as with the f1.7 normal lens. Interesting.

S

[BrianSVP]

I think you have the labels reversed on the images.

[jamaeolus]

Yes. The ones labeled konica are clearly superior.

[Doc Sharptail]

I generally avoid teleconverters, just based on late 70's experiences with 3rd party systems that suffered pretty badly in terms of image quality.

I did end up with a (*I think*) slightly newer variant in a package deal a while ago now:



Kiron 7 element multi-coated converter with the M.C.7 model #.



It came to me new in box, never used. The cheap plastic case for it seems to work well.



There's the converter it's self.



Pretty well a usable image, with the A/I-s nikkor 50mm f1.4 stopped down to f5.6, f-11 effective. I can't see a lot wrong here except for a bit of fringing in the back-ground, where the grey card meets the table top. There's a bit of fall-off away from image center which is not really all that surprising.

I actually have little interest in using this, especially at MFD~ I find extension tubes a little easier to use. Focused off the ground glass at MFD. I'll work with it a little more this summer and try a few distant scenics with it. I'm not expecting much out of it to be honest.

-D.S.

[Alsatian2017]

Stephan, you seem to have the labels reversed, so your text belies the images. Very confusing indeed. While I don't have the Minolta 300-S converter, I can only confirm the quality of the 300-L combined with the MC APO 400 mm f/5.6 lens. At f/16 (effective), the images are nearly perfect.

[caspert79]

Differences are night and day indeed. I’m not surprised that the Minolta is better, but the difference is huge.

[Dejan]

Have you tried the Minolta TC with some longer lenses? It would be interesting to see what it can do with i.e. 200mm F4 prime. I don't expect it would make sense in modern days, but with 50mm F2 it looks better than I would've ever expected.

[stevemark]

[stevemark]

[stevemark]

Using 4/200mm tele lenses in combination with a 2x tele converter was nearly impossible on analog SLRs. The dark viewfinder, the finicky focusing and the film speed neccessary for handheld shots all were contributing to that.

On mirrorless FF cameras with EVF, in-body stabilization, excellent high ISO performance and easy lateral CA correction some of these limits can be overcome.

The combination of the Minolta MD-I 4/200mm with the Minolta MD 2x-S converter is pretty useable, especially at f5.6 (effective f11). Wide open the combo has a lower contrast and quite strong purple fringing. CAs are pretty strong - but not more than other conventional 400mm lenses such as Canon FD 4.5/400mm or Konica AR 4.5/400mm. Details resolution is OK, but not overwhelming; here the Canon FD 4.5/400mm certainly is better.

The Konica combination of AR 4/200mm plus AR Teleconverter 2x is quite a bit weaker, again. More CAs and fringing, and much less resolution, though not as bad as with the 50mm. Not really useable on 24 MP FF, tough.

I am still surprised about the low performance of the Konica AR teleconverter, and if anyone has a sample it would be interesting to dublicate my tests.

S

[jamaeolus]

I have several that came in various lots. Most are...not very good.

[stevemark]

[jamaeolus]

I have the Sony 2x for the A mount. It's pretty good except it only works AF on some lenses. I've gotten decent images with it in conjunction with the 70-400 G. I sold that lens to help fund the newer E-mount 100-400. The only Sony A mount lens I still have is the 200 2.8 APO. I also have quite a collection of Minolta AF lenses that it works with.

[stevemark]

[Dejan]

Thank you Steve that was interesting to see; it's a pretty clear comparison. Yeah, as expected CA is an issue, but like you said it's surprising to see that much of it with the lesser Canon even stopped down. I'd never bet on such result.

[Doc Sharptail]

[stevemark]

[Doc Sharptail]

[visualopsins]

http://www.photosynthesis.co.nz/nikon/lenses.html#TC

[Doc Sharptail]