[Leica] Fwd: Shattered M8 sensor glass update (780 Euros) + soft focus confusion

[geordiepete211 at yahoo.co.uk (Peter Cheyne)]

Ach Ja, ANDREA, nicht Angela!  Danke schoen, Geoff!  And thanks for  
your patient help.

That website about DIY RF adjusting is not very clear to me, and it  
redirects to another site where the English is very unclear and  
besides which, rather sparse, so I'll not try it myself.

Frank, thanks for your opinion.  I do understand your point.  Indeed,  
I looked at my negatives through a loupe (an inverted 50mm Summicron)  
and saw what 'seemed' to be good test results to me.  However, judging  
sharpness on a 35mm negative, taken with a 35mm lens on a test using a  
5mm wide tape measure, where one needs to see actual millimeter marks  
from distances between 50cm and 340cm might tax anybody's eyes.

I scanned the negatives in order to see the details better.  A  
millimeter scale on a thin tape measure recorded on a small proportion  
of a frame of 35mm film is very hard to judge with a loupe alone.  The  
scanned images gave me the data I needed to see in order to make a  
judgment.  I understand that assessing the sharpness of a negative or  
slide through a loupe is advisable when what you have in focus is a  
decent sized subject occupying a decent part of the frame, but when  
you need to judge mere millimeters, shooting an f/1.2 lens wide open,  
from 3.4 metres away, it really is a different story.  At least that  
is what this experience has shown me.

A focus discrepancy that might have been a possible outcome of  
scanning would have been a global focus discrepancy, i.e. fairly  
constant across the whole frame.  It would not alter the focal shifts  
recorded on different parts of the film frame itself.  I mean, it  
could not alter the depth of the field in the frame already  
photographed in the sense of precisely where focus began to become  
acceptable, where it was peak, and where it began to blur out again.   
For example, if your TV goes blurry while watching a movie, you can  
still see what the cinematographer was focussing on, and what the  
depth of field was.  Just the whole image has a global blur added atop  
of it, but in a flat, over the surface way, not in a perspectival, 3D  
way that the original camera only could have rendered onto the film.   
All that I really needed to note was at how many centimeters along the  
tape measure the focus began to appear sharp, at what point it was at  
its sharpest, and at how many centimeters it began to blur out of  
sharpness again.  All that data was in each negative.  Even if  
scanning added a general out-of-focus blur to the negatives, which it  
actually didn't to any noticeable degree, I would still have been able  
to recognize the three important data in each frame, i.e. the two  
thresholds of acceptable focus and the actual focal plane intersecting  
the tape measure somewhere in between.

If you'd like to see more clearly what I mean, the test photos have  
been uploaded here and speak for themselves (dull viewing though they  
are):  http://www.flickr.com/search/?q=test+shots&w=73557746%40N00&s=rec

Please note, these are all very much cropped, and reveal much more  
detail than the eye would be able to see through a loupe.  I am happy  
I followed your advice, thank you, about viewing the negatives through  
a loupe, but I could not view enough detail to judge the sharpness and  
blur threshold lines, especially on the 35 mm Nokton photos at the  
farther distances.

It might be possible, Frank, that I still have not really grasped your  
point, please enlighten me if so, especially if the conclusions I have  
made about my lenses and cameras are in error because of something in  
your point that I have not understood.

All the best,

Peter