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08-19-2010, 05:40 AM   #571
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Sorry, I am kind of lost in this thread, I used the search for over half an hour and just now I gave up and ask my questions via this post.

Imagine you have a K-x with standard 18-55 mm kit lens and you want to extend that with a FAST tele zoom lens and teleconverter.
- First priority is without any doubt candid portraits (without tele converter - I am leaning towards the Pentax DA*), but it would also be nice to be able to extend the reach with a tele converter (and maintain good IQ).

Which lens should I go for?
  1. DA* 50-135 mm F2.8 ED AL [IF] SDM
  2. Sigma 50-150 mm F2.8 II EX DC HSM
What is the best tele converter for each of these two lenses?
- Most reach gain with still reasonable IQ

In my Japanese catalog (I live in Japan, but cannot read Japanese) I get the impression the Pentax 1.4x/2x L converters only work with the DA* 200. I don't know what the 1.4x/2x S converters are compatible with. And the 1.7x seem to be the cheapest, despite I read it actually has internal focussing mechanism that would make manual focus lenses become "auto focus" lenses (by manually putting the attached lens to infinity, to ensure it is within focus range of the converter).
On internet I found that both Sigma converters are compatible with the Sigma 50-150, but also with the Pentax 50x135?
- Do the Sigma's and Pentax S/L converters use focussing mechanism within the attached lens?
- Can I still control aperture via camera on both lenses icw all converters (probably not with the 1.7x, right...)?
- Can I manually adapt aperture on both Sigma 50-150 and Pentax 50-135?

And last question is the 1.7x icw fast old glass any good?l

04-06-2011, 04:15 PM   #572
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what ever did happen with the new TC's pentax was suppose to come out with?
04-06-2011, 05:49 PM   #573
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QuoteOriginally posted by jgredline Quote
what ever did happen with the new TC's pentax was suppose to come out with?
Rumour has it that Pentax Japan thinks that with 14-16MP sensors (giving the ability to crop), TCs are a thing of the past with no place in the digital world.

True story! Pentax Germany said the above to Falk Lumo.

04-06-2011, 07:21 PM   #574
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Is there a nice controlled test somewhere of various TCs vs cropping and resizing?

07-16-2011, 07:24 AM   #575
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QuoteOriginally posted by Miserere Quote
Rumour has it that Pentax Japan thinks that with 14-16MP sensors (giving the ability to crop), TCs are a thing of the past with no place in the digital world.

True story! Pentax Germany said the above to Falk Lumo.


Why don't they launch their "digital auto" telephoto lens(something more than 300mm) in the digital world? TC never past ~ Canon just have new extender
09-15-2011, 08:57 AM   #576
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Kenko P-AF 1.5x Teleplus MC DG

QuoteOriginally posted by danielchtong Quote
Somebody has kindly posted the difference between the SDM non-compatible and compatible one (Kenko 1.5x MC and 1.5x SHQ version respectively)

The MC version is on the left . Notice the missing contact on the left side!!

Hi Daniel,

I'm paying the price for that missing contact you have pointed out. I had been using the 1.5x SHQ version and a similar 2x MC7 version with my DA*300mm and was getting satisfying results. I was able to get autofocus with the SHQ 1.5x as you indicate, albeit with a little hunting in low contrast/light situations. Unfortunately I lost all my TCs when we were on holiday in France last year and got caught in a flash flood and had to escape leaving all our belongings behind. I thought I could replace the TCs but ended up with the latest versions, Kenko P-AF 1.5x Teleplus MC DG and P-AF 2x Teleplus MC7 DG. Not only does the 1.5x not provide autofocus with my DA300 but I can't even access the camera menu which is a real pain. You have to do the settings before putting the lens/TC on. The same applies to the 2x. I have always had to use manual focus with this but I could access the menu and was even able to adjust the focal length on the shake reduction menu (though was never really sure if that actually did much). It's really frustrating when Kenko brings out a new product that is less versatile than the old. Now looking for a Kenko 1.5x SHQ or Tamron 1.4x or Pentax 1.7x. Does anyone know if there are any other brands that work with SDM?

09-16-2011, 01:28 AM   #577
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Would also like to know if the Tam 1.4x can be found anywhere...
09-16-2011, 02:38 PM   #578
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Check Ebay. They seem to run around $240.00 for a used Pentax fit.

09-16-2011, 02:42 PM   #579
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yeah i already did that and only found those that I couldnt afford, thus I opened a separate thread about finding a decent TC for 200 or less
07-21-2012, 09:00 AM   #580
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Was there ever a conclusion about Pz-AF teleconverters with 6 contacts vs. 7 contacts on the camera side? I now have in front of me four Pz-AF teleconverters (Kenko 1.4x, Kenko 2x, Kenko 2x DG, Tamron-F 2x), and two have 6 contacts on the camera side, the other two have 7 (all four have 7 contacts on the lens side).

I don't know if this has been talked about before, but Bojidar Dimitrov has documented what that pin contacts are for in the different Pentax mount revisions. Here's my conjecture on the role of the sixth pin based on his pages:

Features and Operation of the Ka Mount - pin 6 looks like it's "m2" here, "m1m2 encode the minimum aperture: 00 = f/16, 01 = f/32, 10 = f/45, and 11 = f/22. The minimum aperture of f/16 is strange, since only screw mount lenses have f/16 as minimum aperture." If I understand things correctly, with the m2 contact missing, it's equivalent to "always on", so what this does is reduce the range of possible minimum apertures communicated by a lens to the body to just f/32 and f/22, which are easily the most common minimum apertures. (This would also cause mis-reporting of f/16 and f/45 min. aperture lenses when used with a Pz-AF teleconverter with the missing sixth pin, but I have no such lenses to test with so I don't know exactly what the effects would be.)

Features and Operation of the Kaf Mount - pin 6 is gone from KAF lenses, which must mean there's no such thing as a KAF lens with a minimum aperture of f/16 or f/45.

Features and Operation of the Kaf2 Mount - pin 6 is also gone from KAF2 lenses.

I'm really not sure what the significance of the missing sixth pin is on some Pz-AF teleconverters other than it seems to be an intentional revision, perhaps to more closely match a KAF and KAF2 lens mount that the body expects? Maybe a simple cost-reduction during the design revision process?

It also made me wonder about matrix metering, and if the forced "always on" of m2 could interfere with plastic (non-conductive) contacts used to enable matrix metering (talked about on the KAF-mount page):

The next question is then "how can the body distinguish between A-series and earlier lenses (even when the aperture is off the "A" setting)". Some Pentax literature points out that no matrix metering is possible with the A 50/1.2 lens. This lens is the only one whose mount contacts are all metal, i.e. its mount is identical to that of a K/M series lens. All other A lenses have at least one plastic contact. So the bodies must be looking for at least one non-conducting mount contact.
I just surveyed my lenses, and I don't see any that use a plastic contact at m2 (some have a plastic one at m1 though). I did notice that my Pentax FA and DA lenses don't seem to have any plastic contacts though (hmmm).

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