The 1.4X Kenko Teleconverter scam

[David Kilpatrick]

After buying a used white-type 1.4X Teleplus Pro 300 Mx-AF and finding it did not transmit any factor data to the camera - the lens remains reported as its unconverted self in EXIF and presumably for ADI and SSS data - I ordered a brand new black finish Pro 300 DG.

Guess what? In the instructions, only Minolta lenses up to September 1st 1999 are included - that is TEN years ago. The new 'Pro DG' is in fact physically and optically identical to the old Mx-AF, there is not the slightest change in coatings, elements or mechanical or indeed electronic components - mainly because there are no electronics. The instruction sheet states clearly enough that the 1.4X reports 'Actual f-number of prime lens' (it also reports actual focal length of prime lens setting, which is doubling the damage) while the 2X reports 'total f-number of prime lens and Teleplus Pro 300'.

The box says Pro 300 DG, but the 'for Sony AF' label is clearly stuck on over printed wording saying for Minolta, and on the base the converter is identied as M-AF. It does have 8 contacts, but so does the older Mx-AF model in the white-cream finish.

It is plain to see that Kenko have never revised the converter at all, it's a 1990s model still being produced and pretending to be in some way matched to later cameras. They simply rebadged the earlier design as 'DG', and just added dumb extra pins - they claim their converters use 'gate array IC' but there's nothing in this unit at all, you will only find the chip in the 2X models. Their source (presumably a contractor for Hoya) is shared by Tamron, whose 1.4X converter apparently also fails to translate lens data properly to the converted combo. Fortunately my two samples cost less than the normal retail of a single UK stock item (£150 or so - $225). This is already excessive for five very ordinary glass elements stuck in a fixed position in a simple extension tube.

I would have liked a 1.4X converter - the 2X Teleplus MC-7 DG is excellent but pushes my lenses into doubtful AF operation status, while the 1.4X leaves them able to focus well.

Will investigate further.

David

[InTheSky]

Have you tried the Sigma EX DG 1.4x ? I have the EX non DG version, and it's fit on my 70-210mm without any damage, and also other old Minolta lenses.

This is a test for the Tamron standard vs the Kenko, where the kenko perform really well : http://www.pbase.com/lightrules/image/5 ... iginal.jpg

I have found the Tamron white SP 2x version not too bad too. And the Tamron fit almost any lenses. On use market the Tamron are really not expensive.
l know it is not the 2x you are looking at, but this is an interesting test of the Tamron 2x SP compare to the Canon 2x :
http://www.nagelhome.com/phototest/Teletest.jpg (wishing the SP 1.4x is performing like it).

For this link, the kenko pro and tamron are identical ... it is possible that both come from the same factory ? : http://www.pbase.com/lightrules/image/46208989

Regards,

Frank

[alphaPDX]

I recently picked up a used 1.7x for $50us, figuring I had little to lose and a bit to gain. Image quality is acceptable, quite good in circumstances without bright, fringe-able areas. I noticed that it also does not report the true FL/aperture; with only five pins that's not surprising, but still a disappointment. It does nice things with my 70-210/3.5-4.5 so I'm satisfied for now; it does slow down focusing but it's still faster than the Tamron 18-250. More images at http://picasaweb.google.com/alphaPDX/Tc17

This shot was handheld indoors at 360mm, iso400!

[David Kilpatrick]

I'm looking for a converter which works with HSM/SSM. The Sigma does not - it is due for replacement right now with a new model which does. Even the old Kenko works with SSM.

Maybe the problem is that a chip to convert the lens data will also cause problems with SSM, but that seems unlikely as my Kenko 2X MC-7 DG works with SSM.

I may just sell the two 1.4X converters I have now got, and only use the 2X - or I may try to find out whether a third party chip could be fitted.

David

[01af]

I have a really old Kenko M-AF 1.4× Teleplus converter which I bought new in 1987. It is not from the Pro 300 series. It has five contacts and transfers both the effective focal length and effective lens speed to the camera, as it should. Of course it does not support SSM but apart from that, it's a very good tele converter which is only slightly inferior to the original Minolta AF 1.4× TC-II Apo.

-- Olaf

[Andy B]

After buying a used white-type 1.4X Teleplus Pro 300 Mx-AF and finding it did not transmit any factor data to the camera - the lens remains reported as its unconverted self in EXIF and presumably for ADI and SSS data - I ordered a brand new black finish Pro 300 DG.

Guess what? In the instructions, only Minolta lenses up to September 1st 1999 are included - that is TEN years ago. The new 'Pro DG' is in fact physically and optically identical to the old Mx-AF, there is not the slightest change in coatings, elements or mechanical or indeed electronic components - mainly because there are no electronics. The instruction sheet states clearly enough that the 1.4X reports 'Actual f-number of prime lens' (it also reports actual focal length of prime lens setting, which is doubling the damage) while the 2X reports 'total f-number of prime lens and Teleplus Pro 300'.

The box says Pro 300 DG, but the 'for Sony AF' label is clearly stuck on over printed wording saying for Minolta, and on the base the converter is identied as M-AF. It does have 8 contacts, but so does the older Mx-AF model in the white-cream finish.

It is plain to see that Kenko have never revised the converter at all, it's a 1990s model still being produced and pretending to be in some way matched to later cameras. They simply rebadged the earlier design as 'DG', and just added dumb extra pins - they claim their converters use 'gate array IC' but there's nothing in this unit at all, you will only find the chip in the 2X models. Their source (presumably a contractor for Hoya) is shared by Tamron, whose 1.4X converter apparently also fails to translate lens data properly to the converted combo. Fortunately my two samples cost less than the normal retail of a single UK stock item (£150 or so - $225). This is already excessive for five very ordinary glass elements stuck in a fixed position in a simple extension tube.

I would have liked a 1.4X converter - the 2X Teleplus MC-7 DG is excellent but pushes my lenses into doubtful AF operation status, while the 1.4X leaves them able to focus well.

Will investigate further.

David

David,

This chip problem suggests that Sony's in-camera image stabilization might not work when using the Kenko 1.4X Teleplus Pro 300. If so, this would really be self-defeating. I wonder if there are any 1.4X TCs available that do work with SSS.

Andy

[David Kilpatrick]

I need the chip from Olaf's converter to be added to the eight pins from mine. I do not understand why they disabled the conversion of the lens data in the 1.4X, and of course, it would reduce the efficiency of SSM.

Today I am supposed to be getting my new Sigma 70-200mm f/2.8 HSM. I have a Teleplus MC-7 DG 2X converter - which does transmit the data properly - waiting to pair up with this. I am hoping that the results prove better than the Minolta 70-200mm Apo f/2.8 with 2X Apo D converter - I sold both those. I found the Minolta 70-200mm unusable for many close up small subjects due to field curvature on full frame (it is not so bad on APS-C), and the amount of CA produced with the converter was more than expected. At that price, I thought the result should be near perfect.

We have a Sigma 70-200mm f/2.8 new HSM for Richard's Nikon D3 kit, and I was able to do some tests last month which showed it has a much flatter field at close distances while being similar in overall sharpness to the Minolta/Sony for general use (it is a touch soft at f/2.8, the same applied to the Tamron 70-200mm but the Sigma image is cleaner - more like the Min-Sony). Sigma's own converters have not yet been updated to work with HSM, but the Teleplus works, and has proved very high quality so far. It has more elements than the Min-Sony 2X design.

For me, if a 2X converter works well it makes the 70-200mm f2.8 + converter kit far more useful than investment in a new 70-400mm f/4-5.6. The weight and size is less overall, the lens has f/2.8 when used without the converter - which kicks in the centre AF 2.8 sensor of the A700 and A900. With the converter, it's actually much the same f/5.6 that the 70-400mm lens is from 140 to 400mm (I think is f/5 for a little way into that range). The close focus of the master lens is retained in full and close-ups are doubled in magnification ratio compared to the 70-200mm, which focuses down to 1m and gives a 1:3.5 scale - so, 1:1.75 scale results.

The Sony 70-200mm has a 1:4.76 scale at 1.2m minimum focus/200mm - a rather poor close-up ability, which they disguise by calling it 0.21X, easily mistaken for 1:2.1 (which is 0.476X!). The 70-400mm, while a fantastic lens, only focuses down to 1.5m and from my experience, this is restricting - it actually means you can't shoot stuff on the ground near your feet, and in my studio I have to move things round to make space for standing back (when using my still life table, obviously I have more than 1.5m clear for portraits). Also, the maximum close up is 0.27X - 1:3.7, a slightly smaller scale than the 70-200mm Sigma. I find that close-up ability matters a fair amount to me and a small gain in scale can be worth having (one reason I like the Tamron and Sigma 70-300mm f/4-5.6 macro features, which both allow 1:2 or 0.5X in Sony speak).

My final reason for getting a Sigma has been the price, I was able to order one three months ago and lock the price down to pre-increase levels.

But of course it may not prove much use to me, I generally do not use such large heavy lenses at all. Having one in the cupboard at the Sigma price is a different matter to having one unused 98% of the time at the Minolta 70-200mm or new Sony 70-400mm value.

David

[Vidgamer]

I recently picked up a used 1.7x for $50us, figuring I had little to lose and a bit to gain. Image quality is acceptable, quite good in circumstances without bright, fringe-able areas. I noticed that it also does not report the true FL/aperture; with only five pins that's not surprising, but still a disappointment. It does nice things with my 70-210/3.5-4.5 so I'm satisfied for now; it does slow down focusing but it's still faster than the Tamron 18-250. More images at http://picasaweb.google.com/alphaPDX/Tc17

I also bought a used 1.7 (Promaster brand) for $50, but it's been a mixed bag. I know some people have posted that using most TCs is no better than upsizing without one, but it does seem to be a bit better than that. However, it nullifies part of SSS, as SSS obviously doesn't know quite how long you've extended the range, so that's a big problem, and, as you say, any bright fringe, particularly with PF, just gets magnified and is much worse. Auto-focusing is inconsistent and often doesn't work when your lens is f5 or 5.6 at the long end, so maybe it would work better with an f4.5 lens.

The scam with this one is that it's labled a "Promaster Spectrum 7" which you might think indicates a 7 element lens, as the salesman told me. But no, it's just a low-end 4-element lens.

The worst thing might be the problem with focusing. I get too many non-keepers when manual focusing. Sometimes when nailing the focusing, the results are good enough that it's hard to determine which shots were with the TC and which were not. Which I think is an indication that maybe the TC isn't so bad after all, that it does work. It's just less than ideal in IQ and usability. If you can, get a longer lens. (Then you'll be tempted to add the TC to that too! )

So, is it better to get a 2x TC?

This shot was handheld indoors at 360mm, iso400!
...

[David Kilpatrick]

Right now it seems that maximum compatibility comes with the Teleplus 2X (whether 300 series or MC7 DG). Chipped, and good quality, and also the rear element of lenses is not a problem. There are just too many lenses the 1.4X Teleplus can not be used with, including regular standard 50mm f/1.4 - a pity as a 70mm f/2 would be nice combo.

Things I would be interested to see include: Zeiss 135mm f1.8 used with Teleplus 2X - SSM, proper conversion data, 270mm f/3.6 combination and every chance of being very sharp.
Zeiss 85mm f/1.4 (or late Minolta) with the same - 170mm f/2.8 combo.

David

[InTheSky]

If I have time tonight David, I will check if the Tamron 2X SP fits the 85mm 1.4 D. I know his is not the converter you want to see, but this can give an idea of what this can do.

[David Kilpatrick]

The Tamron SP is made by Kenko/Hoya so it's the same as Teleplus basically - as far as I know.

David

[01af]

... as a 70 mm f/2 would be nice combo.

Yeah ... except it would be 70 mm 1:2.4 really. Because tele converters don't transmit lens speeds greater than 1:1.7. Any extra speed beyond this limit will get lost when using a tele converter (no matter whether it's 1.4×, 1.7×, or 2×).

Zeiss 85 mm f/1.4 (or late Minolta) with the same - 170 mm f/2.8 combo.

170 mm 1:3.5 actually.

-- Olaf

[David Kilpatrick]

That depends on the teleconverter design. The Kenko 300 series have really large bits of glass - the 1.4X has a 25mm unit, compared to the MC7 2X with a 20mm unit. The MC7 2X does show f3.5 not 2.8 with a 50mm. But if this effect exists, it must also be related to focal length. I don't have a 20mm f/1.4 or anything like that around but in theory it should not be limited.

Is this a T-stop calculation, or simply a limit imposed by the diameter of the 2X? It is impossible to tell with the 1.4X as it allows 'f/1.4' to be set.

David

[InTheSky]

Quick result tonight ...

FORGET the 85mm 1.4 on the 2X Tamron SP. There is an halo present already in the view finder of the camera (A900) when you put the converter on it. The result are that you need to put the lens up to F2.0 to start having a picture there the halo is not present on the picture.

To validate that, I have install the 100mm F/2.0 on the TAmron SP and the picture are good at the equivalent of 200mm F/4.0.

The adapter is dealing perfectly with the D system (it has 8 pins) : EXIF example at F/6.3 :



Example of the 100mm F2.0 at F4.0 (F2.0 on the lens):


I will post some pictures in the later hours.

Regards,

Frank

[InTheSky]

Here is a example of the 85mm 1.4 with the 2X converter at F/3.5 (Max) :

(100% crop in the center)

Other pictures there : http://www.pbase.com/nadeauf/tamron2xsp

regards,

Frank