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06-07-2009, 09:17 AM   #1
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"A" Extension tubes

I'm looking for a set of extension tubes that lets me control aperture from the camera. I already have a Kenko uniplus tube 25mm, but I'm looking for at least 1 more, preferably a 12mm but I would accept a 19mm. Does anyone know if there is someone out there manufacturing such a beast? Kenko has discontinued making the Uinplus 12 or 25 for the Pentax mount.

NaCl(must get closer, must get closer)H2O

06-07-2009, 10:35 AM   #2
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I've been thinking about A-tubes too. I didnt know about the Uniplus.
So I'll tag this thread and see what turns up.
06-07-2009, 05:57 PM   #3
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Well I have both the Kenko Uniplus Tube 25 and the Pentax Auto Extension Tube K and both are easy to use as they have the coupling to allow automatic diaphragm operation and open aperture metering.
It saves time as you don't have to stop down the aperture before shooting. The Pentax tubes come in 12mm, 19mm and 26mm.



The Pentax tubes are a little hard to find but you may be able to find one on eBay from time to time but obviously prices have shot up considerably.

Last edited by creampuff; 06-08-2009 at 03:54 AM.
06-07-2009, 07:48 PM   #4
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extention tubes

I've been trying to fin extention tubes as well for some times with no luck. The locla store has mentioned that while the Kenko ones are in the book s they are no longer in production and discontinued. I hope Kenko starts making them again or I can find another brand that I can order from Canada.

06-07-2009, 08:10 PM   #5
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I bought a set of these automatic extension tubes when they were around $100 USD. The price has gone out of sight of late - $200 USD at the current exchange rate. They do work well with full aperture control. Haven't seen any others readily available - good luck in your search!
06-08-2009, 03:30 AM   #6
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Thanks Jem, that is exactly what I'm looking for, but 2 bens for a set is a bit beyond what I'm willing to pay. Hopefully if the K-7 gets real popular Kenko will start making the 12 and 25 uniplus for the K mount again. And it that happens hopefully the competition will drive the Polish tubes down.

NaCl(I'm counting on you K-7)H2O
06-08-2009, 03:34 AM   #7
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QuoteOriginally posted by NaClH2O Quote
Thanks Jem, that is exactly what I'm looking for, but 2 bens for a set is a bit beyond what I'm willing to pay. Hopefully if the K-7 gets real popular Kenko will start making the 12 and 25 uniplus for the K mount again. And it that happens hopefully the competition will drive the Polish tubes down.

NaCl(I'm counting on you K-7)H2O

hopefully Pentax will start making their own set again...
06-08-2009, 06:33 AM   #8
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Vivitar also sold "A" Extension tubes, 36-20 & 12mm, Model AT-23.

Luckily I picked up a set on eBay some twelve months back.

Be carefull though, they also sold I think the model AT-22 which do not have the A contacts.

06-08-2009, 06:56 AM   #9
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QuoteOriginally posted by wwwmorrell Quote
Vivitar also sold "A" Extension tubes, 36-20 & 12mm, Model AT-23.

Luckily I picked up a set on eBay some twelve months back.

Be carefull though, they also sold I think the model AT-22 which do not have the A contacts.
Yeah, I just bought some AT-22's, which don't have the A contacts, but are still called "automatic," I guess 'cause they allow stop-down metering (read that on another thread).

I did buy some Kenko AF ones, but they didn't allow me to use live view with SDM lenses (might seem picky, but I wanted to use them with the DA*55), so I thought I'd send those back and go for plain "A" ones... but guess I messed that up too, since now I won't be able to control the aperture on DA/DA* lenses!
06-08-2009, 08:44 AM   #10
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Well, hopefully Pentax will make a set that will allow both. However I wouldn't hold your breath, I would assume a much greater demand for a decent t/c and they haven't made one of those yet either.

NaCl(a new version of the 1.7 t/c would be nice too)H2O
06-08-2009, 08:48 AM   #11
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QuoteOriginally posted by NaClH2O Quote
Well, hopefully Pentax will make a set that will allow both. However I wouldn't hold your breath, I would assume a much greater demand for a decent t/c and they haven't made one of those yet either.

NaCl(a new version of the 1.7 t/c would be nice too)H2O
I think its quite possible that in the year(s) to come pentax will start releasing more accessories. let us not forget just how close pentax corp. came to demise. apparently more than once. if they keep releasing bodies like what they have been putting out with the K20, the k-m and certainly the upcoming k-7 they will get more demand. and with more demand for the bodies and lenses, will come more demand for accessories such as these.
06-08-2009, 09:23 AM   #12
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QuoteOriginally posted by jem Quote
I bought a set of these automatic extension tubes when they were around $100 USD.
It says PKA/AF on the tube, but the text says:

"As for AF engine and TTL auto exposure in modern lenses there is no need to worry, it works perfectly well with extension rings while older lenses with mechanical AF engine will work only in manual focusing mode"

Do they have an AF screw or you you have to use "manual focusing mode" ie focus manually?

Richard
06-08-2009, 09:28 AM   #13
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QuoteOriginally posted by richard64 Quote
It says PKA/AF on the tube, but the text says:

"As for AF engine and TTL auto exposure in modern lenses there is no need to worry, it works perfectly well with extension rings while older lenses with mechanical AF engine will work only in manual focusing mode"

Do they have an AF screw or you you have to use "manual focusing mode" ie focus manually?

Richard

I believe they are describing them as being SDM capable. (SDM only) that's the only thing that would make sense. no screwdrive.
06-08-2009, 10:54 AM   #14
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As I could not find any "A" extension tube, I finally bought a "Takumar A 2x Tele-Converter" which features all the contacts (unfortunately without the electrical contacts for SDM), and removed the lens. This results in a 26mm extension tube allowing full aperture control.
06-08-2009, 11:02 AM   #15
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QuoteOriginally posted by tcom Quote
As I could not find any "A" extension tube, I finally bought a "Takumar A 2x Tele-Converter" which features all the contacts (unfortunately without the electrical contacts for SDM), and removed the lens. This results in a 26mm extension tube allowing full aperture control.
I did this with a teleconverter once myself. before I bought a set of m42 extension tubes (I have no need for A contacts or AF) it worked just as one would expect. if I had pulled the glass out in order and remembered how it went together I could have put it back and used it... live and learn I guess.
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