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04-06-2008, 02:39 PM   #241
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Thanks Georg Reply sent as PM.

For those who may be thinking of trying them, this mob don't take international credit cards, charge between $70-100 freight, plus a $25 banking transfer "fee".

That's on top of the cost of the TC - which would fit into a small postal package.

I guess they must think I came down in yesterday's shower, or else it's an April Fools Day joke....

Nope - not moi!

But thanks for the info Georg - it is appreciated. I think I'll keep on looking. Meanwhile, if anyone in here has a Tamron 1.4x MC4 TC they'd like to sell, then let me know, either via PM here, or to:

pentaxian at fastmail dot fm

Thanks again Georg - your efforts are truly appreciated.

04-12-2008, 04:34 AM   #242
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I have found a third variant of the Tamron converter:
  1. Tamron 1.4x pz-af MC4 with 6 contacts on the body side (works with K20D/SDM)
  2. Tamron 1.4x pz-af MC4 with 7 contacts on the body side (unknown status!)
  3. Tamron 1.4x pz-af MC with 7 contacts on the body side (doesn't works with K20D/SDM)

I will try to clarify the status of variant #2. Anybody able to test it?
04-12-2008, 08:31 AM   #243
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Great catch Falcon.
I suspected there was three.
04-12-2008, 09:05 AM   #244
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QuoteOriginally posted by falconeye Quote
I have found a third variant of the Tamron converter:
The plot thickens!

If the problem is that 7th contact on the body side, then maybe having MC4 status is not enough.

Javier, I'm still waiting for you to put some tape over that 7th contact of the MC to see if that allows it to work with SDM on the K20D.

04-12-2008, 11:15 AM   #245
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QuoteOriginally posted by Miserere Quote
The plot thickens!

If the problem is that 7th contact on the body side, then maybe having MC4 status is not enough.

Javier, I'm still waiting for you to put some tape over that 7th contact of the MC to see if that allows it to work with SDM on the K20D.
Somehow I think that the seventh contact is not that important, maybe it is a dummy for preparing to unknown future features? I think this because even the new Pentax SDM lenses have currently only six contacts!?

Unless if there is some weird cross wiring?
04-12-2008, 01:52 PM   #246
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Ok, I have new detail on the matter.

First, I got the chance to try out this Tamron 1.4x MC4 version with 7 pins (variant #2) I saw earlier today for a short trial.

So I walked to one of the three places around me who carry Pentax gear and have DA* lenses.

The helpful store people let me try my K20D with the Tamron TC and the DA* 50-135 f/2.8.

I used it at 135mm with the light available in the store (sample attached is a 100% crop of it -- so you can judge AF accuracy and EXIF for light conditions). Light (EXIF) was ISO800 1/125 f/2.8 (LV6 -- "light value", i just learn that EV "exposure value" doesn't include iso... -- 1 step already subtracted due to TC).

Now come my findings:
  1. AF converges to focus within about 1 sec.
  2. At focus, it confirms focus about 70% of cases.
  3. At 30%, it just won't confirm focus and won't fire.
In case #3, it doesn't hunt, just doesn't confirm and fire. If it happens, it helps to focus elsewhere and come back once or twice. Also, it usually happened at low contrast rather than high contrast. My feeling was it wouldn't happen outdoor at daylight. However, it also didn't happen w/o the TC. The sample attached is for case #2.

One more detail: when focussing, I got the impression that the AF over- or undershot at each step. It still converged but may have needed more AF operations than usual.

So maybe, the body told the lens "move focus by x/f" but of course used a wrong assumption what f is...
If this is the case I doubt that the number of pins or K10D vs. K20D (or even SDM vs. screw AF) could influence this at all...

So my question is this:
Do we call this a non-working or a working TC?

Does the 6 pin version sometimes fail to confirm focus even if it has reached it?

Last edited by falconeye; 06-15-2011 at 05:27 AM.
04-14-2008, 10:10 AM   #247
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QuoteOriginally posted by falconeye Quote
First, I got the chance to try out this Tamron 1.4x MC4 version with 7 pins (variant #2) I saw earlier today for a short trial.
Thanks for taking the trouble to do this! I think you've proved that the 7th pin is not the problem. Whether it's slower or not, the fact is that AF worked (and I'm assuming the SDM was working, right?). Javier reported that with the MC variant AF simply wouldn't work.

This means that there's something in the MC version that is not in the MC4 that cripples SDM on the K20D, but for some bizarre reason doesn't affect the K10D.

OK, somebody needs to track down the engineers that designed these TCs
04-14-2008, 10:18 AM   #248
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I actually found a Tamron 2x TC so I bought it. It is on its way...I will see how it works, if it works. Price was good.

04-14-2008, 04:47 PM   #249
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QuoteOriginally posted by Miserere Quote
Thanks for taking the trouble to do this! I think you've proved that the 7th pin is not the problem. Whether it's slower or not, the fact is that AF worked (and I'm assuming the SDM was working, right?). Javier reported that with the MC variant AF simply wouldn't work.
Javier?

I am not sure. First, sure: SDM, didn't hear the motor

But then, wasn't the lack of focus confirmation Javier's problem? He only said it wouldn't focus...

If so, it could be explained by the K20D firmware be pickier about "quality of focus" before it confirms...
04-15-2008, 06:01 PM   #250
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QuoteOriginally posted by jgredline Quote
I actually found a Tamron 2x TC so I bought it. It is on its way...I will see how it works, if it works. Price was good.
Where did you find it? I've only seen one on eBay, and it went for a silly amount of money.

I have a 7-element Tokina PKA mount (no AF, of course), but I haven't had a moment to test it yet. It would be nice to pitch them against each other.
04-15-2008, 08:25 PM   #251
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Hey, I found another one...

KEH Camera: Pentax Auto Focus - Converters - 2X TAMRON-F MC7 (PZ, Z, ZX) WITH CAPS, TELECONVERTER
04-15-2008, 08:50 PM   #252
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Not any more Stupid me I sold my 1.4x before I realized what I had. I prolly should of read this thread end to end before I sold it. So I had to take the money that I made selling it and turn around and buy another one, luckily (sort of) on eBay. I am not passing up another deal, the one on KEH was selling for less than the one currently on eBay so I had to snag it, just in case. A DA*400mm f/5.6 I could definitely live with. I'll keep my fingers crossed.

Last edited by Buddha Jones; 04-15-2008 at 08:59 PM.
04-16-2008, 02:10 AM   #253
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This thread just goes on and on........I personally don't see much benefit in 2x v 1.4, but then since I got the DAs yesterday (35 and 300) my LBA has subsided - temporarily, at least! Ha!
04-16-2008, 06:56 AM   #254
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QuoteOriginally posted by John Kovarik Quote
This thread just goes on and on........I personally don't see much benefit in 2x v 1.4, but then since I got the DAs yesterday (35 and 300) my LBA has subsided - temporarily, at least! Ha!
For $55 I am willing to find out
04-16-2008, 07:11 AM   #255
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John,
Where did you get the DA*300?
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