In article <321FCC3D.7B66@AOL.com>, HenryJH@AOL.com says...

>I have a MF 105/2.8 version, which appears to have some elements
>rattling (very slight) inside. Do I need to concern with it? I also
>found that DOF is extremely shallow even at F8 for this lens. Is this to
>do with the rattling elements or the misalignment that you are talking
>about. How do you tell it is misaligned? Thanks.

Many lenses have springs, diaphram actuator levers, etc. that rattle
slightly (and normally) when the lens is shaken. At close-focus, all
lenses have shallow DOF. To check for alignment (at infinity, at
least...), take a vertical photo with the shutter-release end of the
camera up (after carefully focusing the lens manually, and setting the
exposure manually - so that they do not change) of a distant, detailed
horizon placed along the top edge of the frame. Turn the camera over,
and take the same picture again, without changing anything. Examine the
film (with a good 8-10X magnifier) on both sides of the frame line to
see if the same photographed subjects on the two edges (and the opposite
corners) match in detail.
Hope This Helps