[Leica] troubleshooting

[jean.louchet at gmail.com (Jean Louchet)]

>> A black band is showing up on some of my prints. This band
>> encroaches from the right edge of a print (if you think of it as a
>> landscape perspective) in varying widths -- 1/10 of the way into
>> the print all the way up to 2/3. But, sometimes it's not there at
>> all. If I am shooting from portrait perspective, the black
>> encroachment occurs at the top of the image.
>>
>> Regardless of how far it might extend into the image, the remaining
>> part of the exposed image can be just fine, even perfect.
>>
>> The line where the black band meets the "good" image is not usually
>> a clean cut line; I want to say it's fuzzy, soft, less opaque than
>> the rest of the black band. When it intrudes 2/3 the way across a
>> print, it tends to be more clean cut, with a more definite edge. It
>> isn't soft or fuzzy.
>>
>> I am wondering if I have a shutter curtain issue... The bands
>> appear way to organized to simply be a leak. At least, that's my
>> novice notion.
>>
>> Because it IS difficult to rewind a roll of film, I thought it
>> might be a film advance issue. But, none of the images seem to be
>> overlapping each other. If it weren't for the black bands
>> encroaching from the edge, what I composed would still be there.
>>
>> Your thoughts?
>>
Hi,
there is no light leak (it should give black zones on the neg and
white zones on the positive/print). The issue is the second curtain is
faster than the first one. As springs tend to get softer rather than
stiffer with age, it is very probably the spring of the FIRST curtain
that has gone slack and has to be wound up about one turn. This is a
basic, very easy operation - any pro workshop should be able to do
this for cheap. The result is easy to check visually on a M-series
Leica, on a M39 Leica it is necessary to slide the internal assembly
out of the body hence a bit more dismantling but still routine
maintenance.
A word on how it works:
 -on slow speeds there is a timer which determines how long to wait
before freeing the second curtain once the first has been deleased by
the shutter button;
 -on fast speeds the adjustment factor is not a time delay, but a
distance between the curtain edges. On the M series, typically at 1/60
this distance is about 32mm, at 1/125 it is 16mm, at 1/250 8mm, at
1/500 4mm and at 1/1000 only 2 millimeters (this is approximate
values, I don't have the "official" figures).
This distance is set for the start of the curtains. As the two
curtains have approximately the same weight and have similar springs,
they will have the same speed and this distance will be kept during
all the curtains' movement. If, like it is probably the case in yours,
the spring of the first curtain is a bit too slack, the first curtain
will slow down too much towards the end of its trajectory. At slow
speeds this is barely noticeable. At high speeds, it is fairly easy to
get the 4mm or 2mm slot reduced to about nothing towards the end of
the curtains' movement, i.e. on the left side of the negative - which
is the right side of the final picture. THis is why you get a wider
black strip at top speed and slightly narrower at intermediate
speeds..

If I recall, in the M39 Leicas the adjustment screws are directly
accessible once the bottom plate has been removed. On the M series
they are hidden by an easily removable plate.

If you are unsure you may get some training with any old Zenit-E which
has got about the same system. Don't train on a Pentax Spotmatic
(beautiful camera!) but it is the same system again (very nicely made
this time!)

Usually if the top speed (1/1000) works fine, then all fast speeds
(down to the flash sync speed) will also work fine.

Jean
-- 
Jean Louchet
INRIA-APIS 4 rue Jacques Monod 91893 ORSAY Cedex France
jean.louchet at inria.fr   http://jean.louchet.free.fr/
"I will permit no man to narrow and degrade my soul by making me hate
him" (Booker T. Washington)
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