Pentax 67 lens- 45mm f1:4 stopped focusing, any ideas?

[Kleiny41]

Greetings,

I have been using a Pentax 67 and 6x7 for several months now. I have two copies of the 45mm f1:4. One of the lenses won't focus anymore. No focus at the closest focus point, no focus at infinity. I tested whether it was my eyes by shooting a few images and indeed they were blurry. Is there a typical structural problem that can occur which would affect focus like this? Could it be an easy repair?

Many thanks,
Amanda K in DC

 

[loman]

The front ring might have gotten loose, and hence the first glass element. Or the rear group could have gotten loose.
I would look there first.
Best Regards
Mads

 

[Poisson Du Jour]

I have the 45mm f4, SMC-Pentax version (1993). It is one of two lenses in the line up that are my favourites for landscape work, and I consider all of the SMC-P 67 lenses robust enough for solid work.

Other than both the old and new versions being Distagon designs and highly effective in use, it would sound to me that the lens has been dropped and has "locked", with the focusing helicoid jammed or broken. It is unlikely dirt under the focusing ring could cause this, as a noticeable "scratchy"/roughness would be manifest in use. External appearances would not necessarily give away obvious signs of dropping (especially onto a soft surface e.g. carpet), yet even a moderate drop has been known to affect focusing of not just this lens, but also its bigger brother, the 55mm f4 (in one instance, a sharp pull and twist of the focusing ring restored opeation, but ongoingn reliability is questionable). Insight into the glitch may be found by posting your query on the Pentax Forums under Medium Format --> lenses.

 

[John Koehrer]

The first question is whether the focusing ring turns? If it does you should see the lens move in/out.
If it rotates but no movements that suggest something as simple as loose screws in the focusing ring.
If it's not a physical jam, it could very well be a loose element(s)