KR mount lenses will get stuck on Pentax digital SLR cameras. This guide will show a way to remove the Ricoh pin from a KR mount lens. Removal of the Ricoh pin allows KR mount lenses to be mounted on Pentax digital SLRs without getting stuck.

The Lens


The picture shows a KR mount Sears 135mm with macro. This lens has developed a cult following because of distinctive bokeh and color fringes at wide aperture. It has an unusual macro with rotation of the front element. Notice the KR designation at the right of the aperture ring adjustment. DO NOT try to put a KR mount lens on your digital Pentax SLR without first removing the Ricoh pin. Failure to heed this warning could lead to a stuck lens,  expensive  repairs, and possible destruction of the camera.

The Ricoh Pin

Here's the offending pin which sits at about 4 o'clock from the lens indexing linkage visible upper left.

The Body Hole

The hole at about 4 o'clock on the camera body is where the Ricoh pin gets stuck. Inside the hole is the AF linkage for the camera which drives AF lenses.

To remove the Ricoh pin:

1. Remove Lens Mount
Use a small + screwdriver to remove the 4 screws holding the lens mount.
 
Remove the lens mount and flip it over. There's a T shaped metal tab holding the Ricoh pin in place. There's a resistor to the right of the T shaped metal tab. There's a couple screws holding the T shaped metal tab in place. Removing the tab screws is not necessary to get at the Ricoh pin. It's easier to remove the Ricoh pin by simply inserting a knife edge under the bottom of the T shaped metal tab and bending it back.

2. Bend Tab

The tab is bent back exposing the gold colored Ricoh pin underneath.

3. Remove Pin, Reassemble Lens

After the tab is bent back far enough, tilting the lens back allows the Ricoh pin to fall out. That's the offending pin to the lower left of the mount. Now that the Ricoh pin is out, push the bent tab back down. It's not necessary to bend the tab back until it's flush again. After the pin is out, reassemble the lens.

Mounted Modified Lens on Pentax K200

Note the KR designation on the lens. DO NOT mount a KR lens on a digital Pentax SLR without first removing the Ricoh pin from the lens.

Now for some test shots. The vine maple down the street has good fall color.


This shot shows the bleeding colors characteristic of this lens at a wide aperture of f/2.8.


There's less fringe at f/11.

KR mount lenses will get stuck on digital Pentax SLRs. The Ricoh pin which causes KR mount lenses to get stuck may be removed in about 15 minutes, the only tool required is a small screwdriver. Modified KR mount lenses may be mounted on Pentax digital SLRs without getting stuck, becoming the equivalent of KA mount lenses which allow automatic and manual modes.