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Old Jun 27, 2008, 8:02 AM   #1
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Hi All,

Does anyone have a set of the above tubes, pictured below, and if so have you had trouble with the camera not reading exposure details from A lenses. I've a

suspicionthat I've seen information about removing paint from them to solve an grounding problem, but don't recall where or any details. If anyone can direct me to

any relevant info I'd be obliged. ... Jack


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Old Jun 27, 2008, 8:03 AM   #2
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I'd assume if paint needs removing it would be at this end. ... Jack
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Old Jun 27, 2008, 9:35 AM   #3
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Hi Jack,

I am assume that the end that goes to the camera is metal.. On some lenses that Sigma makes the lens mount is plastic with a copper grounding piece. You might want to just take a small portion of th paint off to see if this works.

If it is a platic mount one of those contact should supply the ground. If that does not work, Then you might want want to go back to Jessops and try a different set.

Rudy



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Old Jun 27, 2008, 10:16 AM   #4
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Hi Rudy ... Thanks for your input,

The tubes are all metal construction, butcamera end (secondpic) is either painted or anodised. I can show continuity with an ohmeter between the mounting screws, but

not to the tube body or any of the lens contacts, there is also contact between these screws and the metal collar on the lens end of the tubes as in the first pic. I'm pretty

sure I've seen info at some time re. removing paint. I'm just not sure where this is

necessary, or whether it is needed on all tubes.

There is no chance of going back to Jessops, as I bought these tubes as a used item on Ebay at a very good price compared to buying new, they are in mint condition, I

doubt they've had little if any use, the Jessops branch in my home town has closed anyway, the company has had some financial troubles.









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Old Jun 27, 2008, 10:37 AM   #5
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Hi All,

I think I've solved the problem, I've just been checking. ... on the camera thecontact nearest to the lens locking pinis grounded, also I notice the camera has 7 contacts ,

but the tubes have only 6, my bet is if I remove paint in a position to match the last cameracontact, then that should do the trick, I'll post back when I've tried this out.

... Jack



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Old Jun 27, 2008, 3:50 PM   #6
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looks like an expensive set of ETs.. what did you give for them jack??

roy
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Old Jun 28, 2008, 3:43 AM   #7
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jachol wrote:
Quote:
Hi All,

I think I've solved the problem, I've just been checking. ... on the camera thecontact nearest to the lens locking pinis grounded, also I notice the camera has 7 contacts ,

but the tubes have only 6, my bet is if I remove paint in a position to match the last cameracontact, then that should do the trick, I'll post back when I've tried this out.

... Jack





Well !, that was the problem, I removed paint as described above on one of the tubes, andwith that tube at least everything functions normally, just need to clean

that up a little, and do the same job on the other tube sections and we should be in business.



Roy, when I won that set on Ebay, it was an absolute steal. ... Last time I looked in Jessops catalogue no item for Pentaxwas listed, but a similar set for Canon was

around £100, I won this mint condition set for< £20 including shipping, I was only following the auction out of interest expecting the bidding to mushroom way beyond

what I'd want to pay, when the bidding stayed low I stepped in smartly PDQ (Pretty darn quick). Can you blame me. LOL ... Jack




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Old Nov 15, 2012, 9:04 AM   #8
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I know this is over 4 years old, but if any of you guys are still around - thank you. I recently picked up a set of Jessops PKA tubes and was about to try and return them (an option I did have) until I discovered this. Scratching the area to expose metal on the backplate where the 7th contact is works!

Andy

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Old Nov 15, 2012, 10:35 AM   #9
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Quote:
Originally Posted by alfpics2012 View Post
I know this is over 4 yeasr old, but if any of you guys are still around - thank you. I recently picked up a set of Jessops PKA tubes and was about to try and return them (an option i did have) until I discovered this. Scratching tha area to expose metal on the backplate where the 7th contact is works!

Andy
Hi Andy,

Yeah !, I'm still on the green side of the grass, not too active though, age is taking it's toll.

I'm glad you found that info useful, I made a better job of my tubes with a fine sanding disk in a Dremel tool then masking the area needed then tidying up the paint by applying satin black paint with a fine camel hair brush. It makes a more professional looking Job.

I now use a set of bellows + a slide rail on a tripod, which is a much more versatile arrangement, so my tubes are redundant I should sell them on I suppose. ... Jack
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Old Nov 16, 2012, 10:01 AM   #10
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Hi Jack

I also have some bellows; however shall use both as tubes are easier to manage out in the field!

Andy
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