Re: [Rollei] Rollei 3.5 E Xenotar

[Richard Knoppow <dickburk >]

At 03:01 PM 05/27/2002 -0700, you wrote:
>Jan
>
>I recommend that you keep using your hand-held Weston. if it is accurate.
>Unless new cells are available for the built-in or add-on Rollei meters
>they may be inaccurate.
>
>Maxwell screens are supposed to be the brightest, but I am wary of
>any screens that have the Fresnel element on the upper surface. Frankly,
>I like the Rolleiclear screen with RF prism.
>
>Please don't expect any offers of a Panorama Head until Friday (Marc's Law).
>
>Jerry
>
>
  I second Jerry on keeping the Weston. 
  The main failure of Selenium cell meters is a loss of bright light
sensitivity. You can check the Weston easily. Set up a white card,
preferably large enough to fill the meter's viewing window. Illuminate it
so that it reads 50 on the _Low_ scale. Check the _High_ scale, it should
read exactly 50. If the cell is damaged the low reading will be higher.
  What happens is that the high brightness sensitivity of the meter is
diminshed by a stop or more. The loss is non-linear so can not be
compensated for by simply changing film speed. 
  Weston cells seem to be among the most rugged. Selenium cells are damaged
by heat and by moisture. Weston had a patented method of making the cells
that resulted in better moisture sealing than others. Unfortunately, it
doesn't give it any greater resistance to heat.  If the meter has ever been
over heated the cell will have lost sensitivity. The same technique of
reading the same actual light level on two ranges for checking works for
all Selenium meters, including the one in Rolleiflex's. 
  Since the Master II is calibrated for Weston speeds use the next _lower_
setting to the ISO speed index. i.e., for ISO-100 film set the speed to
Weston 80. 
  The main caution in using the Weston meter is to beware of the very wide
viewing angle. Its easy to get too much sky light when used outdoors. 
  For general use you might find the exposures are closer if the "C"
setting on the calculator is used instead of the pointer. My Weston tends
to underexpose by a stop. I think this is an artifact of a safety factor
Weston used in its speed ratings. According to foot candle measurements the
meter is dead on. 
  If you wan't a new non-battery meter I recommend the Sekonic version of
the old Norwood Director (I've forgotten its current model number). Its
very accurate, and versitile. The only shortcoming is the lack of very low
light sensitivity.
 Weston meters are still made in England by Sangamo. They have a web site
but I don't have the URL handy. I think the current version is too
expensive. 
- ----
Richard Knoppow
Los Angeles, CA, USA
dickburk  

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