Laowa 12mm f/2.8 D-Dreamer Photos and Mini Review

[Birna Rørslett]

Correct, in several cases either version of the PK-11 needs a little help of a Dremel or metal file. The clearance to the camera throat contacts is small and care is required when the extension ring is mounted or removed.

However, that being said, I have successfully used PK-11/11a on every camera model listed by Nikon as being incompatible. All one needs is a bit of common sense and care in the mounting of the extension or its hosted lens.

[pluton]

On a K1 ring the two bayonets are rotated, so if the lens has a fixed petal type lens hood, like many ultra vide angle and full frame fisheye lenses, there will be vignetting.

Good of you to point this out.
Did you know that the Zeiss ZF 21mm/2.8 and ZF.2 18mm/3.5 (and maybe others in the Zeiss line up) have a second petal hood position that perfectly accommodates the rotation of the K1 ring? 

[Erik Lund]

No I have never heard about that

[Thomas Stellwag]

Good of you to point this out.
Did you know that the Zeiss ZF 21mm/2.8 and ZF.2 18mm/3.5 (and maybe others in the Zeiss line up) have a second petal hood position that perfectly accommodates the rotation of the K1 ring?

super - now I know why this  hood has so many positions and vignettes if you are not carefully enough 

[David H. Hartman]

There is a bevel taken out of the meter coupling "thing" inside the PK-11a tube. It rides on a race of dry ball bearings. The bevel is long enough to keep the electronic contacts of AF and AF-D from rubbing against the piece. The meter coupling lever just barely protrudes from the tube to catch the meter coupling ridge on the AI/AIS type lenses. I don't think the bevel is long enough for lenses with more than five contacts.

The meter coupling lever can be removed and then there is clearance for any of the many AF type lenses. The modified tube will be like a short, 8mm M2 tube. I did this modification in the early '90s. Then I reversed it and gave the tube to a school. I think to get the bearings in place I put a dab of grease on each and after it was assembled used acetone to remove the grease. YMMV! Not long after I wanted such a tube to use with a 55/3.5 compensating aperture micro. The 55/3.5 compensating will not mount on a Nikon camera that doesn't have a flip up meter coupling lever but will mount on an M or M2 tube.

I've searched the net but haven't found anything that addresses the issue of a PK-11a and AF-S or later AF lenses.

Dave Hartman

[David H. Hartman]

super - now I know why this  hood has so many positions and vignettes if you are not carefully enough 

You can always use your hand to shade the lens. People passing by may think you are waving to them. In Manhattan N.Y. you'll probably hail a cab.

Dave