SRB Auto Extension Tubes

Anyone own/used a set of K mount SRB Auto Extension Tubes

http://www.srb-griturn.com/slr-auto-extension-tubes-1133-p.asp

Are they auto focus? Are they any good?

from what I can see these are K mount not PKA, ie no contacts. Certainly not autofocus.
I believe all they have is the linkage to stop the aperture down, that's all that is auto about them.
Seem pricey for a basic set of tubes.

It's difficult to say from the photo and description, but I'd agree with moose. These look just like standard 'auto' tubes with an aperture linkage and no contacts. They might have the single contact for use with an 'A' lens, but that's it. Massively overpriced for either type.

Keep an eye out on Ebay.

You could get a nice set of Vivitar AT-22 tubes for around £20-£25 in pristine condition, all-metal and very well made with just the aperture linkage.

£40 or so will get you a nice set with the 'A' contact. A PK/A set with full contacts will normally set you back around £70-£100 depending on the make.

These are PK/A and cheap at present, but I can't comment on the quality:

http://www.ebay.co.uk/itm/Jessops-Extension-Tubes-Pentax-K-Mount-PK-A-X3-13MM-21...

That listing does state "auto metering functions retained" so they must at least be PKA mount, if so then I don't think the price is bad.

There is a set of Jessops PKA on ebay at present.

Jessops tubes are fine. They are re-badged and sold under
various other names such as Aico.

With most of these PKA tubes you have to scrape a bit of
paint off the camera side (of the tube) to form another
contact for use with a digital camera. They work OK with
the Super-A that has an extra contact.

Refer to previous posts on this or the US sites to see
where to scrape off.

The price drop-down menu says pentax K and is £163.50. This would seem quite dear even if they were PKA.I guess you could always e-mail for clarification.

As stated the Jessops tubes are fine.

SRB are always expensive

You can always pop round and borrow my Jessops ones Neil.

[quote:3496ace15f="milamber"]It's difficult to say from the photo and description, but I'd agree with moose. These look just like standard 'auto' tubes with an aperture linkage and no contacts. They might have the single contact for use with an 'A' lens, but that's it. Massively overpriced for either type.

Keep an eye out on Ebay.

You could get a nice set of Vivitar AT-22 tubes for around £20-£25 in pristine condition, all-metal and very well made with just the aperture linkage.

£40 or so will get you a nice set with the 'A' contact. A PK/A set with full contacts will normally set you back around £70-£100 depending on the make.

These are PK/A and cheap at present, but I can't comment on the quality:

]http://www.ebay.co.uk/itm/Jessops-Extension-Tubes-Pentax-K-Mount-PK-A-X3-13MM-21...

Someone paid £102.99 for them What an idiot If someone else had bid £103 he/she would have lost them for a Penny!

Reasonably good price for a set in Pentax mount.

The real madness is that I recently bought the exact same tubes in Canon mount for just under £40.

Someone paid £102.99 for them What an idiot If someone else had bid £103 he/she would have lost them for a Penny! [/quote]---------------------------
Not if their bid was placed first. The £103 bid would not be a big enough increment to beat it. Also people often feel they have just lost an item by the amount they were outbid by but there is nothing to say there wasn't a maximum bid much higher than this already placed - this is how you can end up in a bidding war.

I bid for it a few times but there were obviously at leas 2 others who really wanted it. Without seeing a photo of the contacts I didnt think it was worth the risk

No risk really as they say PK/A on the actual tubes