Archived posting to the Leica Users Group, 1997/10/01

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Subject: Re: Wisdom from the Usenet!, SLRs, vert. focusing
From: Tom Kline <>
Date: Wed, 1 Oct 1997 11:25:59 -0800

>Dan--All this complaining about m-system RF going off is a little
>silly   I`ve had more problem SLRs going off than Leica RF
>my Nikons have had to go to shop    my Pentax 67s (and other
>photographer`s too that I have known) have had problems     All for out
>of alignment focusing screens   Not uncommon at all
>One of my studio mates had a Hassy system that went out      He borrowed
>other studio mates hassy system and began replacing parts     As long as
>he had any part--body lens or back that was his then focus out of
>alignent      He finally sent it off to Hasselblad and they couldn`t
>figure it out either and sent it back unfixed     He finally in
>frustration (and a reshoot of a CD album cover in mexico) sold it off in
>pieces and bought all new
>So obviously Hassy Nikon or Pentax 67 are also not acceptable for
>`professional` work according to our rec/dot/idiot poster
>We backup computers  get our cars tuned up   so why would cameras be any
>Donal Philby
>Kauai Hawaii

Another problem apparently quite frequent with P 6 X 7's is that the mirror
gets out of alignment (position when focusing) resulting in all pix being
out of focus. This can happen with other SLRs too. Both screen and mirror
need to be in perfect alignment!! With AF, there are undoubtably a host of
additional problems that could throw off focus. With an M, one can easily
validate the calibration by using the infinity check. With a standard set
up (e.g., tripod, wall, and meter stick) one could also focus on a known
fixed distance, say 1 M for a near range check. If both infinity and close
range are OK, then the system checks out as two points define a line
(relation of rangefinder position/focus with actual distance).

In landscape mode the rangefinder image moves from left to right as you
focus closer as has been pointed out, this is quite natural for most folks.
Focusing vertical changes the relation so may be giving folks problems. I
typically focus first horizonatally then decide on a portrait orientation -
this works well for handheld MO. Working in vertical on a tripod is a
different case - probably using the coincident aspect of the RF would work
best (e.g. two noses focus into one) unless the picture has horiz. lines
(e.g. tree branches, or horiz. parts of window frames) as these now work
best with the split image aspect.

Thomas C. Kline, Jr., Ph.D.
Research Scientist/ Diving Safety Officer
Prince William Sound Science Center
300 Breakwater Avenue, P. O. Box 705
Cordova, AK 99574, USA