Archived posting to the Leica Users Group, 2001/06/21

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Subject: [Leica] followup to my 28mm focus problem
From: shino@ubspainewebber.com
Date: Thu, 21 Jun 2001 11:41:04 -0400 (EDT)

last week i asked a question about rotten photos from my
2.8/28 Elmarit-M (III) 1979.  over the weekend, i 
ran some focus tests and i think the 28 is definitely screwy.
i had thought that focus problems were more a function of the
body than the lens, but this is clearly not the case here.

i put up the 2200x1780 scans on my site.  they are between 1/2 and
1 meg so they're big.  they are also the filthiest negs i've
ever encountered (probably because its t400cn and it was done in
c-41 soup at a lab).  i didn't spend any time cleaning them prior
to scanning (between dinner and bedtime).

i put the camera on a tripod, put a tape measure with zero against
the tripod center post and centered the focus at the 5 foot mark
of the measure.  (due to the angle, the 5 foot mark is actually slightly
more than 5 feet).

for each test i focused, took an exposure, racked to
focus to infinity, then focused again to and took another
exposures to cover variation due to user focus error.

here's the 28 focused by rangefinder to the 5 foot
mark with the m6 and my 28mm   (pardon for the incredibly filthy negative).
it's off. the point of focus is closer to the 4'4" area.

http://www.shinozuka-family.com/testphotos/m628mm.jpg

as a control, i used my 90 on the m6, other consitions being equal.  it shows
the 5 foot mark clear, and about an inch of DOF.

http://www.shinozuka-family.com/testphotos/m690mm.jpg

for grins, i put the 28 on my CLE which i sometimes use as a backup
for the m6.  oddly enough, focus was close to the 6 foot mark,
or farther away, rather than closer as was the m6/28mm combination.

http://www.shinozuka-family.com/testphotos/cle28mm.jpg

i am thinking the lens itself may have some real problem.  i'm
going to send it in.

since i was shooting so much wide open, i used the rest of the roll
with the old 1.4/35 Summilux-M, (1961 Puts) at 1.4.  kids at the haagen-dazs.
maybe its not considered the sharpest or most contrasty lens on the block,
but it's still nice.  (god those negs are filthy!!!)

http://www.shinozuka-family.com/testphotos/kittyhaagen.jpg
http://www.shinozuka-family.com/testphotos/tedhaagen35.jpg

- -rei