Focus shifting with aperture setting?

[walter]

Anyone else notice the focus changing with aperture setting on their wide aperture lenses? I wonder if this is the cause of some of the focusing issues.

There's more info at diglloyd: A Brief Introduction to Focus Shift and Spherical aberration

You can see how the focal plane moves in the following image from a Pentax-A 50mm f/1.2

Click on the image to view it in a larger size

[Lowell Goudge]

I think what you are seeing is softness of the lens wide open, not a shift in focus.

I sharpened the image in PSPX2 and looked closely, I think the sharpest line is right where it should be