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Old Dec 3, 2007, 8:11 AM   #1
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Hi,

Any one here use AF Extension Tube?

Is it valuable item for macro phothography?

Does Pentax make it?

I like to find one from third party but still can't find one.

Many thanks,

RTogog

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Old Dec 3, 2007, 12:05 PM   #2
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I've kept looking for some, but haven't found any. Pentax dont make any, for sure. Auto focus isn't of much interest, for macro you'd probably have to do your fine tuning manually anyway. What I'm after is the auto exposure metering. Not very important either, but could be convenient when chasing moving objects like insects. For the time being I do quite well with my mechanically aperture coupled Vivitar tubes.

Kjell
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Old Dec 3, 2007, 1:50 PM   #3
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bilybianca wrote:
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I've kept looking for some, but haven't found any. Pentax dont make any, for sure. Auto focus isn't of much interest, for macro you'd probably have to do your fine tuning manually anyway. What I'm after is the auto exposure metering. Not very important either, but could be convenient when chasing moving objects like insects. For the time being I do quite well with my mechanically aperture coupled Vivitar tubes.

Kjell
Hi,
I have a set marketed by Jessops in the UK, I don't know if they still do them, I haven't seen them in their catalogue for a while. They don't come cheap though ... there is a 7 day listing "Buy it now" on Ebay Uk at the moment. As kjell says most people prefer manual focus with macro, I certainly do. Mine are like the pic below. ... Jack.
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Old Dec 3, 2007, 2:33 PM   #4
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jachol wrote:
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Hi,
I have a set marketed by Jessops in the UK, I don't know if they still do them, I haven't seen them in their catalogue for a while. They don't come cheap though ... there is a 7 day listing "Buy it now" on Ebay Uk at the moment. As kjell says most people prefer manual focus with macro, I certainly do. Mine are like the pic below. ... Jack.

Hi,

Is your Extension Tube working with Pentax AF lens but missing its AF fuction? All information on camera as we use Pentax A lens? I found yours on Ebay,looks like a rebadge old Kenko version.

RTogog

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Old Dec 3, 2007, 2:48 PM   #5
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Hi,
The only AF lens I have is the kit lens, and I haven't used the tubes with that yet.( I haven't had the tubes very long). Use has been with mainly manual lenses. I hope I'm understanding you right .. I wouldn't expect AF to work with an A lens (I believe the A setting just allows the camera to control exposure and aperture, focus is entirely manual). Hope this helps. ... Jack
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Old Dec 4, 2007, 2:20 PM   #6
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AF is worthless for doing macros. even if the set, like mine, don't do the ''A'' thing it's no biggie. all you have to do is press the green or Ae-L button each time you switch subjects. the exposure doesn't change much. just make sure you get the kind with the internal lever so it closes down the lens when you shoot the shot. i've gotten 3 sets off of eekbay for under $20usd.

roy
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Old Dec 4, 2007, 10:54 PM   #7
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I think that I have a perfectly adequate solution to most people's need for extension tubes on their Pentax SLR. If you can live with a magnification of 1:2 (50%) on a 50 mm lens, I purchased a teleconverter with all of the matching AEcontacts where the mating surfaces mount to both the camera body flange and the lens mount.My teleconverter is25mm thick. I also use this on my Tamron zoom to get me about 14" closer than normal, which helps me fill the frame more completely.

This match on the pins gets you auto exposure, but not AF. If you think about it, AF gets you a preset focus that is pretty much useless if you are trying to focus on a moving insect or a flower that is waving around in the breeze.

Anyway, the lens element in the center of the teleconverter is usually held in place by a screw-in retaining ring which is easily enough removed and then the lens assembly inside the teleconverter will drop out.

You might possibly get some vignetting (I don't, but you might depending on your lens), but who cares as you are focusing on the center of the image anyway and some vignetting might actually be desirable for kind of a special-effects look.

Ibought my AE teleconverter for a flat $ 12.00 delivered on ebay.

I would think that this is cheap enough for anyone to try out - works for me. Hope this helps.
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