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08-22-2007, 01:23 AM   #1
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Compatibility - Tele Adapter 1.7x & Pentax Lenses

Hullo Everybody!
I am led to believe that the 1.7x AF tele adapter is compaitble only with K and A series lenses. Can anyone here shed light on whether it can be used with F or FA series lenses in AF mode, please? And what can or will happen if one tries to use them on F/FA lenses with AF on?
Thank you all, in advance.

08-22-2007, 06:22 AM   #2
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QuoteOriginally posted by Khukri Quote
Hullo Everybody!
I am led to believe that the 1.7x AF tele adapter is compaitble only with K and A series lenses. Can anyone here shed light on whether it can be used with F or FA series lenses in AF mode, please? And what can or will happen if one tries to use them on F/FA lenses with AF on?
Thank you all, in advance.
The 1.7xAF adapter works fine with FA and DA lenses. The AF is fast, but you have to rough adjust the focus on this lens, and then the AF adater take the fine adustment.

Hopi
08-22-2007, 10:15 PM   #3
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Thank you for the input, Hopi. How efficient is it on a f4 lens - such as a 200mm/f4? Any tele lenses you could recommend that it performs well with? Thanks again!
08-24-2007, 07:18 AM   #4
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Soligor 1.7 teleconverter & Tamron 18-250

Can anybody tell me if the Soligor 1.7 teleconverter (Pentax is nowhere in stock around here) will work with my K10D / Tamron 18-250mm combination?

- Bert

08-25-2007, 11:52 AM   #5
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QuoteOriginally posted by bymy141 Quote
Can anybody tell me if the Soligor 1.7 teleconverter (Pentax is nowhere in stock around here) will work with my K10D / Tamron 18-250mm combination?
Probably no Autofocus at the long end. f/6.3 with the 1.7x teleconverter would give you an effective aperture of almost f/10.7 - too dark for the AF to work reliably. And the Tamron is already a bit soft at the 250mm, using the convert would degrade the Image quality more.
08-27-2007, 01:22 PM   #6
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QuoteOriginally posted by bymy141 Quote
Can anybody tell me if the Soligor 1.7 teleconverter (Pentax is nowhere in stock around here) will work with my K10D / Tamron 18-250mm combination?

- Bert
Your super-zoom is too slow to be useful with a TC. Taken into account, that it reaches a good performance optically, when stepped down another 2-3 aperture steps, will afford an increase in the ISO settings even used without the TC. Add the TC and you will find yourself more often with ISO settings of 400 and higher to avoid camera shake (the SR does help, but it is not a miracle powder...) Also, a super-zoom (nearly 14 x!) is already heavily compromised in the optical quality department, which will only get much worse adding a TC.

If for some reason, unknown to me, you really need to add a TC, you should opt for the very best TC, with the lowest image degradition - and the Soligor is not among those. Perhaps (but only as a last ressort) a Pentax A 1.4x TC or a Kenko 1.5x TC or the Pentax AF adaptor 1.7x might work acceptably.

Ben
08-29-2007, 01:38 PM   #7
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So what about using the Pentax AF adaptor 1.7x on my DA* 50-135mm SDM? I guess the SDM wouldn't work, but will it still have AF?

Last edited by Trub; 08-29-2007 at 01:51 PM.
08-30-2007, 01:53 AM   #8
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It would AF but wouldn't do SDM.

To have SDM, you need relatively old TC with contacts for powerzoom, like the Kenko AF 1,5x.

On the Italian Pentax forum one user had found that it works perfectly with his 16-50.

08-30-2007, 02:29 AM   #9
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QuoteOriginally posted by Ben_Edict Quote
Your super-zoom is too slow to be useful with a TC. Taken into account, that it reaches a good performance optically, when stepped down another 2-3 aperture steps, will afford an increase in the ISO settings even used without the TC. Add the TC and you will find yourself more often with ISO settings of 400 and higher to avoid camera shake (the SR does help, but it is not a miracle powder...) Also, a super-zoom (nearly 14 x!) is already heavily compromised in the optical quality department, which will only get much worse adding a TC.

If for some reason, unknown to me, you really need to add a TC, you should opt for the very best TC, with the lowest image degradition - and the Soligor is not among those. Perhaps (but only as a last ressort) a Pentax A 1.4x TC or a Kenko 1.5x TC or the Pentax AF adaptor 1.7x might work acceptably.

Ben
Thanks Ben,

I guess I have to shop for a bigger lens than.

- Bert
03-17-2008, 03:04 AM   #10
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QuoteOriginally posted by eurostar Quote
It would AF but wouldn't do SDM.

To have SDM, you need relatively old TC with contacts for powerzoom, like the Kenko AF 1,5x.

On the Italian Pentax forum one user had found that it works perfectly with his 16-50.
Also the discontinued Tamron 1.4 TC and the Soligor C/D4 Pz/AF 1.7 (not sure about the current C/D7)
03-18-2008, 07:02 AM   #11
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QuoteOriginally posted by Khukri Quote
Thank you for the input, Hopi. How efficient is it on a f4 lens - such as a 200mm/f4? Any tele lenses you could recommend that it performs well with? Thanks again!
although all the literature states f2.8 or faster, the 1.7x AC TC wirjs just fine on my series 1 70-210 F3.5, and on my smc 300mm F4 and SMC-M 100mm F4 macto.

I have heard reports that it also works well on F4.5 lenses such as the 500mm F4.5 but I have not tried this personally.

It DOES NOT work on f5.6 lenses, or perhaps I should re-phrase this, to does not work on my PZ-1. To be honest, I have not tried on a DSLR with slower than F4 lenses.

As an add on note, I was wishing for extra length last week, and stacked my 1.4x TC behind my 2X tc on my sigma 70-200 F2.8 (making it a 200-560mm F8) it did autofocus in bright daylight nmuch to my suirprise on my K10D but the autofocus ranged in and out a little before reaching focus. I have not yet checked quality of the shots, I only took a few.
09-25-2008, 04:46 AM   #12
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Hi,
Can someone can explain me how to autofocusing M42 lens with my 1.7X AF converter (with pics if possible)?
thx
09-25-2008, 06:50 AM   #13
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QuoteOriginally posted by Djteddy Quote
Hi,
Can someone can explain me how to autofocusing M42 lens with my 1.7X AF converter (with pics if possible)?
thx

Short out the contacts between the lens and 1.7x AF with a piece of tin foil. It will auto focus just like any other k mount lens attached to the teleconverter.
09-28-2008, 05:24 AM   #14
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Thanks a lot.
09-28-2008, 08:41 PM   #15
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Khukri (or anyone else), I'm not sure if the point was made & understood based on some of the follow-up questions, but it should be understood that any AF capability that a lens has, is nullified by the 1.7X AF TC. The most modern lens will act as a manual focus auto-aperture [A] lens when coupled to the 1.7X AF TC. You get the lens "close" in focus, then the TC takes over to bring the focus point in-focus. The AF TC takes in the screw drive to move its moving element, but does not pass it along to the lens. Likewise using a K or M lens, you still have to get the focus close manually and TC does the rest. You just have to contend w/not having the auto aperture adjustment w/the latter and play the lens aperture ring + button press + rotator dial "video game" to get aperture and exposure set-up right.
QuoteOriginally posted by Lowell Goudge Quote
I have heard reports that it also works well on F4.5 lenses such as the 500mm F4.5 but I have not tried this personally.
Can any reader who has the 500mm/4.5 & 1.7x AF TC confirm this? I'm keen on getting this lens and would like the option to use it with the 1.7x as an AF combo. But search on this board keeps returning nothing searching for any combo of (500 or 500mm) and (4.5 or f4.5 or f/4.5) etc... and I'm sure there are threads containing the text... search just can't deal w/it.
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