[NaClH2O]

Except for P-TTL flash I see no value in manual focus extension tubes having aperture contacts

Any Kmount auto tubes support open aperture focusing and will stop down the lens when shooting

Metering with green button works the same and with macro and manual focus I dint see any other issue. Flash would be the biggie

I agree that except for the flash auto tubes are essentially unnecessary, but speaking from one who does a fair amount of macros, it's damn convenient to change aperture with the rear e-dial. Especially hand held. I'm all for convenience, otherwise I'd be shooting with a K1000

NaCl(it's not required but it IS easier)H2O

---

Last edited by NaClH2O; 11-03-2010 at 08:27 AM. Reason: word choice

[omega leader]

Remember extension tubes can also be used to reduce the minimum focusing distance of long lenses, to allow it to focus on say small birds ect.

They don't have to be only for macro.

[Lowell Goudge]

Nacl2 and omega leader

My macro lenses are pentax k or m42 so rear dial is no issue and the two lenses I have that from time to time need reduced minimum focus are the k300/4 and a vivitar 400/5.6 neither with A contacts

I know what you mean but they are of no issue. There are not many A lenses with 22 foot minimum focus and macro is not really an issue whe you are already MF

[cloudphreak]

I'm trying to understand this, maybe I am not searching well enough or plenty of folks here will agree with my frustrations. why does it seem that automatic extension tubes are not in production by any manufacturer for pentax k mounts?

But now i would really like it if I could use my DA lenses, or use the automatic aperture setting, and have automatic metering. Come to find, there seems to be tubes out there but they are not made today, made years ago, and are extremely hard to find.

Coincidentally, I had been looking for exactly the same thing, and had given up. By shear dumb luck, I was on Amazon today and found this:

Amazon.com: Kenko Auto Extension Tube Set F/ Pentax-AF: Camera & Photo: Reviews, Prices & more

They had one set for $169.00 (shipping from CambridgeWorks) so I snapped it up without even thinking. It has supposedly already shipped, so hopefully I'll know in a few days if I really bought what I'm hoping I bought.

Also, it looks like this other site might have the same thing for $179.00:

Kenko | Auto Extension Tube Set DG For Pentax AF *FREE SHIPPING* | AEXTUBEDGP | Tri-State Camera, Video, and Computer

[Ira]

(.... scratching my head, not sure what Ira means, Tuesday must be one of my slow days....)

I'm not sure why an extension tubes with electrical contacts is "an unnecessarily expensive accessory."

To me, these are either necessary or at least, very convenient to have:

- The tube can be used with any lens that normally fits a Pentax body, including lens without aperture ring.

- The camera can control the aperture of the combo (tube + lens) just like it does the aperture of the lens alone.

- You can have full-aperture focusing, a feature very much needed because focusing is critical and has to be done manually. The dim viewfinder (due to the tube) makes this even more important.

- You can have p-TTL flash metering.

I guess what I'm trying to say is, I don't see anything different with shooting a manual lens and $10 extension tubes or shooting auto with $200 tubes.

They're just tubes--not even a piece of glass!

[RXrenesis8]

Coincidentally, I had been looking for exactly the same thing, and had given up. By shear dumb luck, I was on Amazon today and found this:

Amazon.com: Kenko Auto Extension Tube Set F/ Pentax-AF: Camera & Photo: Reviews, Prices & more

They had one set for $169.00 (shipping from CambridgeWorks) so I snapped it up without even thinking. It has supposedly already shipped, so hopefully I'll know in a few days if I really bought what I'm hoping I bought.

Also, it looks like this other site might have the same thing for $179.00:

Kenko | Auto Extension Tube Set DG For Pentax AF *FREE SHIPPING* | AEXTUBEDGP | Tri-State Camera, Video, and Computer

Well, are they all that they say or not?
7 electrical contacts?
Aperture lever?
AF screw?

Details and pictures please!

[cloudphreak]

Well, are they all that they say or not?
7 electrical contacts?
Aperture lever?
AF screw?

Details and pictures please!

Don't have them in front of me at the moment, but there are electrical contacts, and there is aperture control. No AF.

[excanonfd]

Patience grasshopper patience
They can be found you just have to have patience. I scored a 25mm Unitube plus in K mount on eek bay after looking for about 6-8 weeks and it just so happened that the guy was only about 10 miles away. I also scored a set(I wanted more than just 25mm) from someone here. Watch the forum here and have e-bay watch for you. They ARE out there. If you get a set of the rokunar 6 pin types you can scratch a mark in the mount for the 7th pin and they will work as well as any other auto tubes. Or do likedrougge suggested and make one from an old cheap TC.

NaCl(if you wait they will come)H2O

I am interested in this 'scratching a mark' procedure. Do you have any pictures or diagrams on where to put the mark to get AE features?

Thanks,

[SOldBear]

I am interested in this 'scratching a mark' procedure. Do you have any pictures or diagrams on where to put the mark to get AE features

[excanonfd]

SoldBear,

Thanks for pointing this out, I was looking at my CPC TC mount and comparing it to the Pentax F1.7x TC mount trying to figure out where the mark should go, your post confirmed my own conclusion. Scratching up the finish on the TC so that the contact on the body mount touches is sufficient? What about moving the seventh pin on the TC to the correct position? Your thoughts would be appreciated.

Thanks,

[SOldBear]

Scratching up the finish on the TC so that the contact on the body mount touches is sufficient? What about moving the seventh pin on the TC to the correct position?

I'm not sure what you mean by "moving the seventh pin on the TC to the correct position." To me, scratching the base of the TC (or extension tube) to ground the seventh pin is sufficient.

The seventh pin is used to transmit focal length, distance to the subject, exact absolute f-stop value, lens size, and MTF data from the lens to the body. With the TC or the ET between the lens and the body, the focal length, f-stop, and lens size data, if exist, are incorrect any way. Grounding the pin won't be any worse than transmitting incorrect data.

[excanonfd]

I'm not sure what you mean by "moving the seventh pin on the TC to the correct position." To me, scratching the base of the TC (or extension tube) to ground the seventh pin is sufficient.

The seventh pin is used to transmit focal length, distance to the subject, exact absolute f-stop value, lens size, and MTF data from the lens to the body. With the TC or the ET between the lens and the body, the focal length, f-stop, and lens size data, if exist, are incorrect any way. Grounding the pin won't be any worse than transmitting incorrect data.

You have a 12mm extension tube from the AT-23 set and the 2x TC converted to ET. Comparing the two, is there any difference in the exposure accuracy between the AT-23 ET and the TC-ET? If there is no difference, then simply grounding the pin is sufficient but if the AT-23 is more accurate then there is a seventh pin on the TC-ET located about 1cm left of the scratch mark point that can be moved to the grounding point. There is no contact at that location on the Pentax DSLR body, so I am assuming that the pin can be relocated without consequences.

I have scratched the point where the seventh pin should be just now and the TC-ET seem to be working as it should; showing the aperture value in the P mode, but I haven't had a chance to test it against an AT-23 for AE accuracy between the two.

Thanks,

[hoanpham]

If you're setting up for serious macro work with tubes, auto is a pretty moot point.
Why do you think you need or want that for proper exposure, especially since center weighted and spot manual metering works so perfectly for macro type shots?
That's why you don't find them. It's an unnecessarily expensive accessory.

Same here, can't see any benefit of it.

You can also get them from Cyberphoto in Sweden
Mellanringar systemkameror Dörr Mellanringsats 13/21/31mm till Pentax

~$200 for a set? serious? Someone may have too much funding...

what i need is $5 reverse ring, $20 tube-sett, maybe 2, and $50 macro focus rail.

[blende8]

German company Dörr is making a set with 13, 21 and 31 mm exension tubes with KA contacts for Pentax.

http://www.doerrfoto.de

The photo is for the Nikon version, but I have seen the Pentax version in real life with contacts.

Here they are for 109 Euro Foto Palme Online Shop - Dörr Zwischenringsatz 13/21/31 mm für Pentax
Technikguenstiger.de Online-Shop - Dörr Zwischenringsatz 13/21/31 mm für Pentax

Thank you very much!
Didn't know this.
The price is quite high though and perhaps one should look around for a used set.

I have a Kenko tube, which even works with SDM, but it is not produced anymore. Nice with the DA200!

[Lowell Goudge]

They still show up at B&H