Originally posted by womble <begin nerd warning>
Some time ago I purchased a Pentax copy stand P. This is a collapsible copy stand that I thought might be useful for the work I do. Here is the beast:
As you can see, one has a much deeper attachment plate, and the rail mechanism is reversed. How very curious. I suspect that my copy stand is an early model (Phil has a P-III) and I wonder if the change in the attachment plate reflects larger cameras, or perhaps one with a motordrive? Whatever the story, I'm glad I can now use my stand with my digital SLR by swapping out the two rails.
<end nerd warning>
I have just the Pentax close-focus rail, although there were many times when I was tempted to purchase the collapsible copy stand back ing the 1970-80's when doing a lot of specimen photography at remote locations.My unit has the long slot.
I have two complaints with the Pentax close-focus rail:
1) The fitting is not tight, there's a lot of loose wiggle when the rails are not locked, so you dare not take your hand from the focus knob when using one in vertical orientation or the rig will immediately drop to the lowest position.
2) The lock lever and the rack-&-pinion knob are on the same side making it awkward at best to lock the rail after getting the camera into focus.
I have multiple rails now, including the old Pentax unit. Except for size, almost all the others are superior to the Pentax unit, but none of them are perfect.