This is most interesting.  A few months ago I used one of Bruce's D cameras
with my manual lenses.  For a while at least the focus indicator was
active, and I relied on the indicator while manually focusing.  I noticed
later that a lot of the photos were "soft."  Fast forward to this past
month during which time I've been using a 5n, also with manual lenses. 
During this period there was plenty of time to fiddle around with the gear,
and I noticed that the focus indicator would come on and remain on through
a few degrees of focus adjustment.  IOW, the indicator was not precise.  Of
course, there's only one precise plane of focus, so by relying on the
indicator instead of your eye and your focusing skills, focusing accuracy
could be compromised, especially with fast lenses used wide open.

Now, let's move ahead to today.  Godfrey wrote: "The focus indicator light
is illuminated through 10-15  degrees turn of the focus ring with all of
these lenses, so for f/1.7 and f/1.4 lenses, it simply cannot be trusted at
wide open aperture."  His observation supports my observation.

Jumping back to the last NorCal get together, at some point during the day
Bruce suggested that I turn off the focus indicator on the D, which I did.
Unfortunately, I hadn't learned about the diopter correction on these
cameras, and the correction wasn't set properly for my vision, either with
or without glasses, so while focusing accuracy improved somewhat as a
percentage of shots, it still wasn't as good as it could have been.

Bottom line: turn off the focusing indicator and use your eyes, be sure the
diopter correction is set properly, and, finally, have your eyes checked
and have the camera viewfinder diopter thing set properly for your vision. 
It may, in some cases, require that you get a new diopter thingy installed
just for your specific vision, although the D and DS, as well as the 5n,
seem to have a pretty wide range of correction - more than, for example,
the LX. 

Shel 

> Don Sanderson wrote:

> Here is a quick comparison of the "Wide Open" performance of my
> like new SMCP-A50/1.4 and one of my rather dusty SMCP-M50/1.4
> lenses.
> Both at 1.4, both focused on the mailbox using the in focus indicator,
> shots within a couple of minutes of each other.
> Shot just before dusk in indirect light. On the ist-D.
> JPEG straight from camera, no post processing.
> Any idea what could be wrong with A?
> It looks and acts perfect but the image quality below 5.6 hoovers!
> By 5.6 they're about equal, at 8 and smaller the A wins. :-(
 
> http://www.donsauction.com/pdml/A_vs_M.htm


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