Re: Re: Re: [Rollei] Planar Sharpness

[Richard Knoppow <dickburk >]

At 05:53 PM 04/04/2002 EST, you wrote:
>
>In a message dated 04/01/2002 7:55:12 PM, you wrote:
>
>>>I have an F w/f3.5 Planar, 5 element version   t is usually quite 
>>>sharp centrally at all apertures, but has to be stopped down to f11 to 
>>>achieve edge to edge sharpness.  The lens looks good as far as I can
detect 
>>>and has been examined by both Harry Fleenor and Marflex and pronounced
fit. 
>>Harry Fleenor examined it, said all was well.  Krikor at Marflex said there 
>was a spacing problem, purported to fix it, but the lens still performs the 
>same.  My only other clue is that the right edges of the negatives (left
when 
>in camera) seem fuzzy compared to the sharp edges of the other sides.  That 
>could mean the pressure plate isn't holding the film in proper alignment (or 
>could mean nothing).
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>BTW, my search for a solution to this problem was how I found this list to 
>begin with, and although I have benfitted much from its collective wisdom,
my 
>Planar is still sub-par.  All I have left at this point is incurable 
>optimism.  
>
>Allen Zak
>
>
  Not the pressure plate. The lens board is tilted. The F has adjustments
for parallelism on the four tubular rods which locate the lensboard.
Earlier cameras use shims. The lensboard can be out of alignment even if
the trim panel is even all around compared to the front of the camera body.
Its aligned with shims. 
  Checking parallelism requires a machinists gauge and a flat. The
reference surface is the edge of the lens cell. It can also be checked with
an autocollimator and flat mirror.
  If there is noticable defocusing at one edge it indicates considerable
tilt. 
  Another possibility, although not very probable, is a tilted lens
element. Most lens cells are such that the components can't be tilted, at
least without chipping or cracking them. The chance  of the lens having an
element or component which was edge ground off center or with the axis
tilted is very remote but could have a similar symtom. 
  If the camera was in the hands of Marflex or Fleenor not too long ago you
might find out if either checked the parallelism. Marflex at least should
have an autocollimator, I don't know if Harry has one, probably he does. 
  The nature of the film gate in the Rollei is such that the film is
straight unless the back plate has suffered severe and visible damage. The
film actually runs in a narrow channel between the outer set of rails and
the back plate. The clearance is changed with switching from 6x6 to 35mm. 
- ----
Richard Knoppow
Los Angeles, CA, USA
dickburk  

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End of Rollei Users list digest V10 #230
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