Pentax 28mm shift- any experience? drawings?

[Dan Daniel]

I know someone with this lens- the Penatx 28mm f3/5 shift lens in K-mount. There is slop in the shift movement and the offset indicator has been reversed in some form so that it indicates 11 when centered and 0 when offset to the maximum.

Before doing some exploratory surgery, I was hoping that someone has some idea what is going on at the shift/rotation mount. If so, any experience, photos, drawings, advice much appreciated. Thanks!

 

[John Shriver]

I got one that had been rather crudely converted to Canon EF mount, but thankfully came with the original Pentax mount. It's really pretty obvious just starting from the back removing screws. (However, I rate high on mechanical intuition.) Under the mount, there's a ring held by screws that holds together the rotating click mount. Take that off and you get the rear knurled ring off, and expose the shift mechanism. Watch out, there are steel balls for the detents which will gladly fly away. (But are also dirt cheap to buy a bag of on eBay.)

The offset indicator running backwards would indicate that the gear that drives it is mis-meshed. As you dial up to 11, the end of the sliding mount with the green dot should go "in".

The slop is probably loose screws in the offset mechanism. The outer parts of the keyway (on front part of lens) are held in with screws. Perhaps they're a bit stripped, or the wrong size?