Some thing to say about the 6x7 adventures

The 300mm is apart again and the cause of the focus error is the second element from the front.  The retaining ring has loosened and enough so that the element shifts about 2 to 4mm to give a focus error of maybe 8 to 100 feet depending on point of focus.  To get to the retaining ring will require the separation of the outer and inner barrel/sleeve to the front group.  This is not an easy job since the separation point is loaded with crud and oxidation as well as Pentax tends to put a tread lock material on the joints.  So I don't own the tool to do this opening bit, so I'm going to build one.  The slots that the tool must fit are small 5mmX1.5mm slots and so the tool can't miss or it is going to ruin the flange.  I figure I'll need around 50+ foot pounds to opening...isn't that a lot?  I'll also need a custom cut vise saddle for the barrel.

On the other front... I finally landed a 75mm/F4.5 lens.   Yes the really sharp one!  So at some point I've got to test this lens out... Oh sadness and joy.