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Old Apr 23, 2008, 10:12 AM   #1
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Tamron adaptall2 PKA


i've got one of these but it doesn't work as a PKA mount.. it does well as a PK mount but will not transmit aperture value to the camera.. anybody else had this problem?? know a fix??
i've also got a short tamron zoom that only works with a PKA adapter from f8 and above..

both of mine lock and will go into the AE setting. it's just on of them has no AE.. what's weird is that even the cam will not display the ap value you can rotate the wheel like always and the cam will stop down. when you ck the image it does show the different f-stops..
roy
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Old Apr 23, 2008, 10:58 AM   #2
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Hi Roy,

The problem is usually due to a bad ground in the PK/A adapter. just to the left of the last contact pin, you'll see the end of a screw coming into the adapter base from the other side. The theory is that Tamron used a thread sealer to lock this screw in position, and the excess was wiped off, but a very thin residue remains, and this thin film insulates the area preventing a ground here with a pin on the camera body. try scraping about a 1/4" area around the screw end with a knife blade. Clean away the scrapings and blow off the end of the lens and try it on the camera. If you still have no aperture show up, in the VF, enlarge the area a little at a time until you get a solid contact (try not to scrape too deep, you don't want to make a dip in the metal). I've had some that required clearing as much as @ 3/8" to make the right contact.

I've had this problem with all my PK/A adaptors (I have 5), and this trick has worked with them all.

Scott
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Old Apr 23, 2008, 4:22 PM   #3
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dude!!!!!!!!

that's what it was!! i used a finger nail file and sanded 1.4'' t the right and 3/8'' to the left. all seems fine now this was part of a consignment of 30 lenses i'm selling for someone. i thought this was toast..

anouther problem i'm having is with another tamron lens. when i put a pk/a on the lenses in Av ut works but only from f8 - 22. the lens is a 70-200/3.5-4.5


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Old Apr 23, 2008, 4:29 PM   #4
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never mind. that fixed it..

roy
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Old Apr 24, 2008, 8:08 AM   #5
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Thats excellent, I have one of those on my Tamron SP 200-500 f/5.6 and it only dispalyed the Av if I undid the lock and rotated the lens a notch.

When I get a chance I will give it a quick file and see what I get.

PK
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Old Apr 24, 2008, 11:33 AM   #6
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i used a paper file. some 150-200grit sand paper should work well.. or use the powder in one of your shells.. spread evenly and ignite. needs to be smokeless tho..
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Old Jun 24, 2008, 4:44 AM   #7
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snostorm wrote:
Quote:
Hi Roy,

The problem is usually due to a bad ground in the PK/A adapter. just to the left of the last contact pin, you'll see the end of a screw coming into the adapter base from the other side. The theory is that Tamron used a thread sealer to lock this screw in position, and the excess was wiped off, but a very thin residue remains, and this thin film insulates the area preventing a ground here with a pin on the camera body. try scraping about a 1/4" area around the screw end with a knife blade. Clean away the scrapings and blow off the end of the lens and try it on the camera. If you still have no aperture show up, in the VF, enlarge the area a little at a time until you get a solid contact (try not to scrape too deep, you don't want to make a dip in the metal). I've had some that required clearing as much as @ 3/8" to make the right contact.

I've had this problem with all my PK/A adaptors (I have 5), and this trick has worked with them all.

Scott

Hi Scott,

Great information !. ... I examined the area you outlined above, and noted there was

a machined groove in line with the lens pins, not wanting to use any harsh abrasive,

I found that a few seconds work just in the groove area with an HB pencil, then

blowing away the residue with a bulb blower, and a slight polish with a clean cloth

did the trick nicely. Thanks very much. ... Jack.



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Old Jun 24, 2008, 2:16 PM   #8
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nah jack,
it's the lead that's conductive. you for one should see that.. hehe

roy
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