Archived posting to the Leica Users Group, 2010/05/27

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Subject: [Leica] Fwd: Shattered M8 sensor glass update (780 Euros) + soft focus confusion
From: geordiepete211 at yahoo.co.uk (Peter Cheyne)
Date: Thu, 27 May 2010 19:22:37 +0900

Thanks, Frank, for clarifying how you perform the test.

I found that my M3 and M6's RF alignments are very close to each  
other, that I cannot tell a difference.  So the negatives from the M3  
look like the negatives from the M6, with the differences being down  
to what lenses are being used.

As to the lenses, I found that my 50mm Summicron is spot on.  The  
focal plane is where I focused with the RF, with the out of focus  
areas properly in front of and behind that plane.  Nice to know.  The  
Tele-Elmarit is front focussing, but not as badly as my Nokton.  My  
Tele-Elmar's front focus is such that the point where I focus with the  
RF is just in or just outside of (depending on distance from lens) the  
rear fringe of acceptable sharpness.  The Nokton, at all three  
distances, was not focussing where I focussed the RF.  It was front  
focussing far too much, such that at the farthest distance in my test  
(340 cm) the lens focusses about half a meter in front of where I set  
the RF.  At all distances, with my Nokton wide open, the intended  
plane of focus was significantly behind where the lens actually  
focussed.

The question is what to do next.  Today I sent my two Leica lenses to  
Solms, because Andrea Frankl suggested that I send them there to make  
sure they work well with my M8.  I told her I noticed discrepancies  
between the M8 and the M3 & M6 regarding front/back focussing.  When I  
used the Summicron on the M8, I had to unscrew the front part from the  
rear part of the lens and reverse the shim.  Because one rim of the  
shim is flat, and the other rim comes to a point, this made the lens  
ever so slightly longer.  I then screwed the front back on, and  
finally unscrewed it slightly, so that is held but was not completely  
tight, and made the lens slightly longer yet again.  Then I found the  
M8 could focus the 'Cron.

I am confident that when the M8 and Leica lenses are returned to me,  
they will work together as well as possible.  But I am slightly  
worried that when they come back, the 'Cron will no longer work well  
with the film cameras, and the Tele-Elmarit might be even more mis- 
aligned.  On the other hand, maybe all the members of my little Leica  
family will play very nicely together and live happily ever after.   
The thing is, if they don't all play nicely when reunited, I'm not  
sure what to do, short of then sending everything back to Solms.   
Anyway, I've pretty much decided to think about properly when my  
parcel arrives from Solms.

As for the Nokton, it seems it is badly out of focus on my film  
cameras, although it was focussing better on my M8.  Again, I probably  
won't decide what to do about that until my M8 and Leica lenses come  
back home.

In a nutshell, I found that my film cameras were probably not out of  
RF alignment, and that my Nokton lens was to blame for recent  
unintended soft-focus photographs, due to severe front-focussing.  I  
also found my Tele-Elmarit was front-focussing, not as badly as as the  
Nokton, but enough for me to want to get it seen to by a Leica  
technician.  I was nicely surprised to find the Summicron was spot-on,  
despite the fact that it needed a troublesome workaround to focus well  
with the M8.

Thanks for helping me think about this, Frank.  It was confusing me  
for a while.

All the best,

Peter