i have only found pro optic's auto extension which is 85 dolar in Amazon, Adorama....
Amazon.com: Pro Optic Auto Extension Tube Set for Pentax-KPR Mount, 3 Tubes.: Electronics
i sent e-mail to adorama whether af is available or not and i am waiting for answer.
ii couldn't find any alternative to "pro optic" which is a little expensive for me...
ii don't expect using af with 3 tubes, but i think i can use af up to 25 mm (like kenko's) if af is available like canon's pro optic extensions.
any suggestions???
thanks
halil