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11-09-2010, 10:18 AM   #1
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Auto Extension Tube Set

I saw an Auto Extension Tube Set on eBay and it seems to indicate that it passes the Aperture setting through the set thereby facilitating metering. Anyone have any experience with these? The tube set I ordered is simply a static series of rings that move the lens away from the sensor but without any mechanical pass-through component.


11-09-2010, 10:54 AM   #2
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QuoteOriginally posted by Docrwm Quote
I saw an Auto Extension Tube Set on eBay and it seems to indicate that it passes the Aperture setting through the set thereby facilitating metering. Anyone have any experience with these? The tube set I ordered is simply a static series of rings that move the lens away from the sensor but without any mechanical pass-through component.
I have a set of these, I forget where I ordered them from and what brand though. (Not eBay, but I think they are no longer available. Auto tubes for K-mount seem to go in and out of manufacturing at random.)

Most eBay extensions I've seen were non-auto - Basically a K-mount to arbitrary threaded mount (for the tubes, which all had a threaded mount) back to a K mount.
11-09-2010, 11:24 AM   #3
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QuoteOriginally posted by Entropy Quote
I have a set of these, I forget where I ordered them from and what brand though. (Not eBay, but I think they are no longer available. Auto tubes for K-mount seem to go in and out of manufacturing at random.)

Most eBay extensions I've seen were non-auto - Basically a K-mount to arbitrary threaded mount (for the tubes, which all had a threaded mount) back to a K mount.
These appear to be in good shape but are older. The box has "MiJ" on it and the tubes appear to be K-mount. I think I may try to snag them for $10 and see.

Ah well, sniped out from under me. Should never have mentioned it, I know better.

Last edited by Docrwm; 11-09-2010 at 01:15 PM.
11-09-2010, 11:36 AM   #4
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For metering to work it should pass trough the electrical contacts and the aperture lever. Without the former the body won't consider it an A-lens or newer, without the latter the body cannot control the aperture.

11-09-2010, 11:56 AM   #5
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"Auto" can means different things. Don't assume anything.

A jolepp said, to pass the aperture info, the extension tube needs to have electrical contacts on the mount.

01-16-2011, 08:47 PM   #6
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QuoteOriginally posted by SOldBear Quote
"Auto" can means different things. Don't assume anything.

A jolepp said, to pass the aperture info, the extension tube needs to have electrical contacts on the mount.
I been looking for a set of these for 3 years.
01-17-2011, 12:23 AM   #7
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QuoteOriginally posted by Fl_Gulfer Quote
I been looking for a set of these for 3 years.
Note the one on the right in the photo is not really an extension tube per se. It is a 2X teleconverter with the optics removed.

I have only one extension tube as the one on the left. But I have three copies of the one on the right.

IME, it's easier to look for a teleconverter than for an extension tube.
01-17-2011, 01:49 PM   #8
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OK I have a 2x TC that I removed the optic's by just unscrewing it. I really want a set of Vivitar AT-22 or AT-23 ext tubes.

01-18-2011, 02:06 AM   #9
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Only the AT-23 has the electrical contacts and give you the functional equivalent of an A series lens, AT-22 will function as same as an M series lens (shoot in M mode with green button for metering) with KAF2 mount bodies.
01-30-2011, 04:42 PM   #10
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I just got an A-22 set thinking it was an A-23 set. They have an aperture lever but I can't manually set any lenses aperture in-camera. As such all lenses without aperture controls on the lens itself always shoot wide-open. I guess older cameras could automatically set the aperture without any lens data?
01-30-2011, 04:51 PM   #11
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QuoteOriginally posted by RXrenesis8 Quote
I just got an A-22 set thinking it was an A-23 set. They have an aperture lever but I can't manually set any lenses aperture in-camera. As such all lenses without aperture controls on the lens itself always shoot wide-open. I guess older cameras could automatically set the aperture without any lens data?
Not exactly. "Non-crippled" K-mount cameras have an analog aperture coupler that passes non-A aperture data to the camera. "Crippled" K-mount cameras lack this aperture coupler which is why non-A lenses only work with stop-down metering.

Features and Operation of the crippled Kaf Mount
01-30-2011, 05:31 PM   #12
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I was wondering what that other lever was for!

Since the AT-23 passes data, metering should work with the crippled Kaf mount right?
01-30-2011, 05:50 PM   #13
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QuoteOriginally posted by RXrenesis8 Quote
I was wondering what that other lever was for!

Since the AT-23 passes data, metering should work with the crippled Kaf mount right?
Correct.
01-31-2011, 03:10 PM   #14
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It's very hard to find a set of AT-23's . I was going to get a cheap Full Auto 1.4 TC for $85.00 and take the lens out but the guy said that the lens wouldn't unscrew like the manual 2x TC's.

Last edited by Fl_Gulfer; 01-31-2011 at 03:17 PM.
01-31-2011, 11:04 PM   #15
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Mmm... I have a Tamron 2x auto TC (fun fact: it's a little less that 2x, maybe 1.9!) that I was trying to sacrifice for this purpose but as you mentioned it doesn't exactly screw out. There are a lot if tiny springs and levers in there to move around...
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