have had this problem before with Sigma lenses, 105 Macro and 50-150 f2.8. on a k5 , the iis and K3ii. Tamron Adaptall or any non af lens works as the book says.. It appears the data pin has to be blanked off or an mf ext tube fitted which does the same thing. There is a posting on the american site where users on that have had the same problem, certainly with Sigma.

have lens switch set to manual, shutter button half press set to OFF,camera set to AF-S, Aperture priority. AF button on enable. shutter triggers regardless of being out of focus, AF in cancel position situation the same. If i enable AF button and put an mf ext tube on lens hold AF button on and hold shutter release on CIF works. Did find an article on American site where the situation i have was found on some lenses and the cure was to blank off the data pin with a piece of foil.

K5iis shutter releases even with AF button and Half Press(focus priority) focus have both been disabled, Pentax 17-70 SDM and Tamron 90mm Macro lenses tried. Am i missing something in settings. Trying to get CIF to work with the Tamron.

another great set John, we just let Tesco do the growing for us as we tried it once and complete disaster

Excellent shots and a real stunningly colourful post

+1 to everything said

not much to choose from . Sigma 50-150 +13mm ext tube,

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have bought quite a few items from MPB and had no problems , they have a sigma 17-50 f2.8 in as well. My current camera came from them.They give 6 month guarantee whereas SRS give 12 months again bought quitea few bits from them with no problems.

MPB and SRS have 16-45 lens for sale

Once again thanks for comments. The light was quite helpful filtering through trees and flowers David. Thanks John , don't know what you mean