Fitting old lenses on DSLR

A dealer set up my K20D with my old Super Takumar 1:4/150
I cant get it to focus but it used to.
Any suggestions?

Nothing the dealer could have done to the body would affect the focussing ring on your lens. Has the focus ring jammed or something?

Might be barking up the wrong tree, but isn't this a 42mm screw mount? If you have just lost focus at infinity, it could be due to the k to screw adapter.

//Edit
I must stop posting after three glasses of wine; sorry

It should focus just the same as it always did, manually! Do you mean you cannot get the full focussing range from it, or perhaps you mean get a correct exposure reading using it. Just to confirm, is it an m42 screw mount fitting? Would you elaborate a bit further.

John

Check the M42 to K-mount adaptor. If it is the type that fits entirely inside the K-mount on the camera (i.e. the camera body is flush with the back of the lens) then it should focus as normal. If it is the type that has a wide flange that sits against the back of the lens and makes the lens sit slightly proud of the camera body, then the lens will not focus to infinity as it is now a different distance from the sensor. Always use the flush-fitting type of adpators and you should have no issues. I have one fixed permanently to each fo my M42 lenses and they work just like k-mounts.

Regards
David