[RockvilleBob]

I just purchased a Pro-Optics 2x Teleconverter for Pentax Autofocus cameras see Pro-Optic 2x Tele-Converter for Pentax AutoFocus SLR 2XPX

I noticed a review for a 1.4 teleconverter which doesn't seem to be listed at Adorama anymore. I will be trying this with HSM Sigma 70-200 2.8 lens and let you know the results.

If you have experience with this teleconverter - let me know - thanks.

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Last edited by RockvilleBob; 04-30-2012 at 03:17 PM.

[Adam]

Have you received the TC yet? How is it?

Personally I didn't even know that a TC that retained AF functionality even existed (apart from the F 1.7x). If the IQ this thing produces is decent, it might be worth reviewing!

[baro-nite]

I have the 1.4x version and have reviewed it. I expect the 2x version works the same, based on the photos in the Adorama listing (you can see the Pz contacts on one side but not the other, just as in the 1.4x). That is, works correctly with DA-type lenses (and I would guess with F- and FA-type lenses), but not with DA* lenses. I'll also venture a guess that the optics in the 2x are the same 4-element optics in countless other 2x TCs sold under various brands.

[RockvilleBob]

The converter arrived but I am traveling so I will test it next week. If it doesn't work with DA* lenses I will return it since it was advertised as autofocus. My guess is that the Pz comments above by baro-nite are probably correct but I had to try it to find out. I find it very frustrating that getting an HSM autofocus teleconverter for is so difficult, I find it difficult to accept that Pentax does not offer one after withdrawing an earlier version from the market. I've had my K-5 for about a half year after getting rid of my Sony Alpha stuff in an effort to do more HDR photography (the A77 options for HDR are very poor) I don't mind the new lens policy since it hasn't had a chance to shake out yet, the announcement of an upcoming 560mm lens is good for my wildlife photography interests. I have the DA*16-50; Sigma 70-150 2.8, Panagor 90 f2 macro, Helios 77M 58 f1.8, SMC 55 f2. With the Leitax adapter I also have two old Olympus lenses working a 400 f6.3 and 85 f2. I am acquiring a K 35 3.5. So all I want is a teleconverter for the Sigma 70-200 to use outside and save my money for the 560. It seems like a little thing but not being able to get a fully functional teleconverter is very frustrating when I have a great camera and some very good lenses. I just do not understand what is so complicated about the Pentax HSM that makes it the only camera company without a fully functional teleconverter. Overall I am very pleased with the move to Pentax but the teleconverter issue is a thorn in my side and would probably have led me to Canon or Nikon if I had known about it in advance, I didn't give it a second thought.

[baro-nite]

It seems like a little thing but not being able to get a fully functional teleconverter is very frustrating

That sums it up well -- I'm sure there are engineering challenges to come up with a TC that is compatible with all K-mount types, but after so many years you'd think it would have been done. Oh well, the new roadmap shows something slated for next year; maybe this one won't fall through.

You are aware of the Kenko/Tamron TCs with working Pz contacts? I don't know if they work with Sigma's HSM or not, but they do apparently work with all Pentax lenses. (Sigma's own TCs don't do HSM either, do they?)

[RockvilleBob]

I tried the Sigma teleconverter - I spoke with Sigma and they said they said it wouldn't work. I know about the Kenko/Tamron but will not buy one unless eBay seller will accept a return if it doesn't work with Sigma HSM. I am just hoping the Ricoh acquisition works out well - my best guess says it will but I've had a bad track record. I bought Olympus OM series and they quit the business for awhile for the snapshot market. Bought the first Sony Alpha after they bought Minolta and they just can't seem to make a full featured DSLR - the A77 multi-bracketing options are pathetic. There is nothing that comes near the K-5 in bang for the buck from Nikon or Canon so I went with the K-5 - Again I am happy I got the camera - I've been able to add some great lenses at a reasonable price - I am looking forward to the 560 (assuming it is affordable for me to get one) - I am sure the follow on to the K-5 will be another suburb camera BUT the teleconverter is a thorn in my side.

[MegaPower]

That sums it up well -- I'm sure there are engineering challenges to come up with a TC that is compatible with all K-mount types, but after so many years you'd think it would have been done. Oh well, the new roadmap shows something slated for next year; maybe this one won't fall through.

You are aware of the Kenko/Tamron TCs with working Pz contacts? I don't know if they work with Sigma's HSM or not, but they do apparently work with all Pentax lenses. (Sigma's own TCs don't do HSM either, do they?)

Only Tamron 1.4x and "Kenko 1.5x teleplus SHQ" works with ALL AF pentax lenses.
Other Kenko/vivitar/etc with Pz contacts only work with screw drive AF. That means all DA* with SDM and Sigma HSM will not work.

Pz = Power zoom.
This are used for FA series lenses with power zoom.

[baro-nite]

According to bdparker's review here is a 2x that works with Sigma HSM. Might even be optically reasonable as it is the 7-element version.

Kenko Teleplus Kenko Pz-AF 2X Teleplus MC4 Lens Reviews - Miscellaneous Lenses - Pentax Lens Review Database is another report of a TC working with Sigma HSM, although apparently only in good light.

[RockvilleBob]

I decided to return the ProOptic 2x teleconverter since the comments I received indicate it will notwork with Sigma 70-210 SDM lens except in manual.

My interest is wildlife photography and I have a manual 400mm f6.3 Olympus OM lens with a Leitax adapter working on my K-5. I think I will just wait to see the price of the Pentax 560 - about the same reach as the 400 Olympus and compare optics. Naturally the Pentax will have autofocus.

I will save my money for a Kenko or Tamron 1.4 type teleconverter for use with the sigma - giving me up to 300.

Really a shame that Pentax is the only mount for which the Sigma teleconverter does not support SDM autofocus. The lack of teleconverters is a major drawback for wildlife photographers using Pentax. I don't see how Pentax can let this happen.

[luftfluss]

The lack of teleconverters is a major drawback for wildlife photographers using Pentax. I don't see how Pentax can let this happen.

Consider that Pentax has had limited funds and indifferent ownership in recent years. Serious wildlife shooting is more of a niche than landscape, portraiture, etc. Wildlife shooters can use one of the Sigma 500mm lenses.

Fortunately, it looks like Pentax's new owner is more on the ball than the previous.

[RioRico]

Has anyone compared IQ of rear-mounted vs front-mounted TCs? Rear-mounted eat light; front-mounted don't. Quality front-mounted TCs in the 1.4x-2x range exist from Sony, Olympus, Canon, Panasonic, Kowa. These have no effect on focus nor aperture automation; my Sony 1.5x VCL tele-adapter on my FA50/1.4 turns it into an AF 75/1.4 with (to me) barely noticeable IQ loss. A rear-mounted 1.4x TC would make it a 70/2 and I don't know if IQ would be any better.