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11-27-2015, 03:10 PM   #1
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KAX 2x Macro Teleplus MC7 help

I recently bought one of the above units and was trying it out on my SMC Pentax-FAJ 75-300mm zoom. Disaster, could only see a faint black image. Next lens to try was my Sigma 100-300mm set aperture ring to A, same faint black image. Changed the manual aperture ring to f4.5, image clear with light, when stopping down to f22 image returns to faint black. I assume this teleplus works the same as any manual teleconverter with lenses that I am using, only lenses with manual aperture control will work. Some say it only works auto with lenses faster than f2.8 only?
I also noted two aperture control levers, one extending into the camera body not spring loaded controlled by the lens aperture ring. A second aperture ring on the other side of the of the teleplus barrel that is spring loaded.
My question is does non spring loaded aperture ring meant to be this way, or is it broken? The retailer of the teleplus said he will refund my money if this is the case. Hope someone with a similar unit can help.

11-27-2015, 04:15 PM   #2
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Does this tc have electrical contacts ie PKA mount or not?
11-27-2015, 05:16 PM   #3
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I have a Vivitar 2x Macro focusing teleconverter and it works just fine with lenses with no aperture ring. However, mine has a full set of contacts. So the first thing is to determine if yours has contacts or not. I believe this was made both with and without.
11-28-2015, 02:23 AM   #4
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Thanks for the replies. My teleplus is the same as this one
https://www.pentaxuser.com/images/comment_pictures/1032/1032_1355318490.jpg
The lever on the left side of this picture is the aperture control that springs. The lever that is floppy is at the other end of the teleplus.
Thanks all.


Last edited by galelegg; 11-28-2015 at 04:25 AM.
11-28-2015, 03:40 AM   #5
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Perhaps the auto aperture lever has been mutilated by some previous Canon owner.
11-28-2015, 05:15 AM   #6
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QuoteOriginally posted by galelegg Quote
The lever on the left side of this picture is the aperture control that springs. The lever that is floppy is at the other end of the teleplus.
This is normal. if you mount on the camera without a lens then the camera pushes the levers together.

If the lens aperture is indeed not being opened up correctly when mounted then a mechanical problem is a real possibility. With the aperture ring on "A", any misalignment or disconnect along the linkages will leave your lens on f22 = way dark pics! Inspect the aperture lever on the lens to see if it seems to be working correctly and isn't bent or tweaked out of alignment. ditto the tc. Inspect the operation of the aperture lever with tc mounted on the lens.
When you posted you did set mode on the camera to Av didn't you? cos if you didn't that's probably the problem! An electrical probelm could still be the cause: is the camera showing f numbers on the lcd display (in Av, aperture ring on "A")?
Do some more tests - try as well manual mode as well does that work?

Last edited by marcusBMG; 11-28-2015 at 05:20 AM.
11-29-2015, 05:01 PM   #7
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QuoteOriginally posted by marcusBMG Quote
This is normal. if you mount on the camera without a lens then the camera pushes the levers together.

If the lens aperture is indeed not being opened up correctly when mounted then a mechanical problem is a real possibility. With the aperture ring on "A", any misalignment or disconnect along the linkages will leave your lens on f22 = way dark pics! Inspect the aperture lever on the lens to see if it seems to be working correctly and isn't bent or tweaked out of alignment. ditto the tc. Inspect the operation of the aperture lever with tc mounted on the lens.
When you posted you did set mode on the camera to Av didn't you? cos if you didn't that's probably the problem! An electrical probelm could still be the cause: is the camera showing f numbers on the lcd display (in Av, aperture ring on "A")?
Do some more tests - try as well manual mode as well does that work?
Thanks to all for suggestions. I decided to start again with a proper tryout with the KAX teleplus.
Mounted my Pentax 20d on a tripod in my backyard and focused on a nearby gas heating flue in the house behind. 9.30am clear sky sun behind me and camera shaded by the verandah. Attached the KAX teleplus followed by Sigma 100-300mm 1:4.5-6.7 DL. Input focal length screen appeared set it to 600mm. ISO set to 800 camera mode set to Manual. Focused on gas flue with the lens set to f4.5 (light needed so I could see image), then switched the lens back to A. Turned the aperture wheel on the camera to as wide open as the dial would allow F1.4, the shutter speed indicated 200 this is with exposure bar in the centre, took photograph with a cable release cord attached to camera. Photo came out as under exposed. Turned shutter wheel to 60 left aperture on F1.4 photo came out near perfect.
As a further test I detached the KAX teleplus and attached the same Sigma lens to a TELEMORE 95 II 7•K•M•C teleconverter all manual no electronics at all to the Pentax 20d and got the same photo of the gas flue, Manual mode setting, same ISO 800. The same looking photo was taken at F4.5 Shutter speed 640. I placed the KAX back on the camera turned the camera aperture to wheel to F4.5. Shutter on camera indicated 20 took photo and also came out with the same type of exposed picture. Turned lens aperture dial back to F4.5 camera gave me F-- pressed green button shutter said 640 took photo and the same result as the TELEMORE. Conclusion, appears that Teleplus maybe working in a fashion or that it is very, very slow through the camera, for my needs virtually unusable for bird photography. Will have to start again looking for an auto teleplus or converter, unless some body has a better suggestion.
11-29-2015, 05:39 PM   #8
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Remember you lose 2 f-stops of speed with a 2x teleconverter.

If the image darkens in the viewfinder when you turn the aperture ring or is dark when set to "A" then the auto-aperture stop-down lever is not working on the teleconverter. Green button metering works because the camera reads the light coming through the lens. Is the lever as long as it is on the lenses? If not then it was cut down by a previous Canon owner.

The viewfinder should not darken when you stop down unless you have the optical DOF preview enabled and enganged.

Post some pictures of both ends of the mount of the TC from a few different angles if you can.

What body do you have?


Last edited by Not a Number; 11-29-2015 at 05:54 PM.
11-30-2015, 05:05 PM   #9
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Decided that I would follow recommendations and adjust the aperture lever that extends back into the camera it was on a slight angle bent inwards towards the centre of the lens. Applied the long nose pliers and moved it outwards about 1-1/2mm and after reattaching it to the camera the black haze disappeared immediately. This morning took SMC Pentax-FAJ 75-300mm zoom, KAX 2x Macro Teleplus and my Pentax 20D into the bushland park and exposure worked great,could even get P mode photos. The only aspect that was not available for which I was hoping is auto focus, this was my original objective in buying the KAX teleplus. I have included a picture of the one I own. From my original research I found a diagram which I am sure was on pentaxforums outlining the purpose of the 7 contacts, I have not been able to find it again. On 1st photo contact 1 going from right to left about 6mm from the phillips head screw the contact is sitting on its own, this is the auto focus contact? If it is, the one on my lens does not work, any suggestions. Thanks all.
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Last edited by galelegg; 11-30-2015 at 05:29 PM. Reason: Not completed
11-30-2015, 05:22 PM   #10
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QuoteOriginally posted by galelegg Quote
It was contact 1 going from right to left about 6mm from the phillips head screw, this is the auto focus contact? If it is, the one on my lens does not work, any suggestions.
No picture attached.
The contacts have nothing to do with AF. Except for the SDM contacts which are located inside the mount, not on the mount, and i doubt are present on your TC. For AF to work you need a screwdrive slot.
11-30-2015, 05:23 PM   #11
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AF is mechanical screw drive (except on sdm lenses etc) this tc does NOT have AF. Looking at your camera front AF screw drive is between twenty and twenty five after position.
11-30-2015, 05:25 PM   #12
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Here is the article on the k-mount contacts: The Evolution of the Pentax K-mount - Articles and Tips | PentaxForums.com
11-30-2015, 05:52 PM   #13
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The TC has only 6 K-mount pins and one "Ricoh" pin. The 7th pin is often called the data pin and carries information such as the focal length, focus distance and variable aperture information. Without the data pin the eDial will always let the f-stop to the widest value be set. Thus a DA 18-55mm f/3.5-5.6 can be set f/3.5 at 55mm. Actually it would be f/11 (f/5.6 + 2 stops due to the TC).

Last edited by Not a Number; 12-01-2015 at 12:07 AM.
12-01-2015, 01:55 PM   #14
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Thanks all for your great replies to an area of photography I have struggled with for many years. Even back to the 1970's trying to photograph cricketers, 400ASA black and white film, Pracktica SLR camera no light meter 200mm zoom + 2x teleconverter. Hardly took a shot worth while keeping. Just one further question, would I have to look for a teleconverter with KAF, KAF1 or KAF3 fitings to have autofocus?
12-01-2015, 03:19 PM   #15
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QuoteOriginally posted by galelegg Quote
a teleconverter with KAF, KAF1 or KAF3 fitings to have autofocus
and a lens fast enough to let enough light through, AF starts to struggle going past f8 (as in your wide open effective f stop is only f8 with tc with a lens that is f4 without tc; only f11 if the lens without tc is only f5.6)...
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