----- Original Message -----
From: "Daphne" <[EMAIL PROTECTED]>
> I noticed something else bout the 50/1.4-K, it seems to focus just a bit
> beyond the chosen spot..? could focus be off? or more likely its just me
> not being used to the heftier focusing ring?
>
> Daphne
>
The lens by itself can't focus on the wrong plane, although the focus scale
can give the wrong indication if you're scale focussing. Any error will be
in the system behind the lens up to and including your own eyes. The ground
glass area of the screen is the most accurate place to determine focus.
Focussing aids such as split images and microprisms depend on an aerial
image which is not confined to a single plane (as it would be on ground
glass) so any imperfection in your vision will throw the image to a
different level. Also, there can be calibration faults in a camera's mirror
or screen position that can cause a difference between correct focus on the
ground glass and at the film plane.
Try this, preferably with a wide angle lens, it has more critical depth of
focus (not field!) than standard or tele lenses. Lay out a tape measure
from zero at the film plane (focus scales measure from the film plane)
leading away from the camera. Focus at the 1 metre mark and take a shot at
the widest aperture. Check two things. Does the lens scale indicate 1m?
This is not absolutely important as the focus ring may have been badly
realigned after a repair, or slipped out of calibration, and this won't
affect the sharpness when you focus visually. Is the resultant photo
focussed at 1m? This is the acid test. An error here means a CLA at least
is indicated for your camera.
Hope this helps.
Regards,
Anthony Farr
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