From: "Mark Roberts" <[EMAIL PROTECTED]>
> Ian Fleming <[EMAIL PROTECTED]> wrote:
>
> >I have noticed that my MX ,bought used,does not quite make infinity
> >on focusing,I have tried the lenses in my LX and they are OK.I have
> >tried reseating the focussing screen to no avail.any ideas?
> >A service is in order I suspect.
>
> Either or both of two things that could be wrong: The position of the
focusing
> screen or the film-to-lens-flange distance (the latter is set with shims
between
> the camera's lens flange and the camera body).
A third problem could be that the mirror is not resting in the proper
position.
> You need to give a little bit clearer description of the problem you're
having.
> Find a subject far enough away to be accurately in focus when a 50mm lens
is
> focused at infinity (check with another camera). Mount the 50mm lens and
set it
> wide open (maximum aperture) and focused at infinity. Take some pictures.
There
> are three possibilities:
>
> 1) The viewfinder image is out of focus but the exposed image on the film
*is*
> in focus.
> -- This would mean the focusing screen position is out of adjustment.
Or the mirror is out of adjustment.
> 2) Both the viewfinder image AND the exposed image on the film are out of
focus.
> -- This means the film-to-lens-flange distance is wrong and shims need
to be
> changed to correct it.
Correct.
> 3) The viewfinder *shows* that the image in focus but what comes out on
film is
> NOT in focus.
> -- This means that the film-to-lens-flange distance is off and that
someone
> has foolishly adjusted the focusing screen to try to compensate.
Or the mirror position was off and the film-to-lens-flange distance was
foolishly adjusted. This happened to me.
I have had 4 cameras with this problem, 3 LXs and 1 ME Super. The problem
was the mirror in every case. In one case, the repairman that Silvio's (LA)
sent my LX to foolishly adjusted the film-to-lens-flange distance to
compensate. My camera tech then had to fix both problems. Note that for
maximum resolution with a fast lens at wide aperture, the distances have to
be held to within several ten thousandths of an inch. The adjustment should
be made by a professional who has the proper optical measuring equipment.
Regards,
Bob...
-------------------------------
"In the carboniferous epoch
we were promised perpetual peace.
They swore if we gave up our weapons
that the wars of the tribes would cease.
But when we disarmed they sold us,
and delivered us, bound, to our foe.
And the gods of the copybook headings said,
'Stick to the devil you know.' "
--Rudyard Kipling
-
This message is from the Pentax-Discuss Mail List. To unsubscribe,
go to http://www.pdml.net and follow the directions. Don't forget to
visit the Pentax Users' Gallery at http://pug.komkon.org .
