Zeiss Ikon Diaphot User manual

I  CEIJJ             I
   The Exposure-Meter
         "Diaphot"





                                                                                           Digitally signed by Mike Butkus
                                                                     DN: cn=Mike Butkus, o=Butkus camera manuals, ou=butkus.org,
                                                                          email=mike@butkus.org, c=US  Mike Butkus               Date: 2023.04.05 20:38:43 -04'00'

solves the question of exposure for the novice or expert in a
simple and practical manner and with the. utmost accuracy.
  The meter is of the visual type, the correct time for exposure
being ascertained by viewir,g the actual subject through a  little
blue window and reading tbe required exposure opposite the lens
aperture you desire to use.
  No calculations are necessary.
  On looking through the eyepiece and turning the outer ring
of the instrument, the window will gradually darken  till  it be-
comes oPaque.
   The correct exposure may be determined by turning the ring
till all shadow details of the subject viewed are at vanishing point.

www.butkus.us
      INSTRUCTIONS
    Take the Diaphot in one hand, holding it tight by the small ring.
    Then taking the instrument between the thumb and forefing.. Jf
     the other hand and turn it  till the blue window appears in the
     opening under the star. Now examine through this window the
     object to be photographed, and turn the outer ring till all the
     details in the shadows begin to vanish while the details in the
     high lights remain indistinctly visible.
      The details in the high lights of a landscape shourd be seen
    only as blue spots on a dark back ground, the whole looking
             like a landscape seen by moonlight.





         Picture seen wrth the naked eye         Picture as it should be seen through
                                                        the Diaphot
      Having found the correct density (which will be very simple
     after-a little practice), examine the face of the meter and you will
    see in the opening of the dial, opposite the lens apefture you
    wish to use, the correct exposure tirne for a normal juulect witrr
   a plate or film of the speciar rapid variety, say Kodak Film or'    Imperial Special Rapid plate.
'      This exposure time will be the correct one for distances from
    about 9 yalds to infinity with normal plates or films of a speed    of about 250 H & D.
       For distances from about 4rlz to 9 yards, double this exposure time,
   and for less than 4rlz yards increase it three times. Ordinary
    indoor views require also at least a three times increased .*po"rrri.

                                       3

On high mountains or by the open sea, the original exposure
time must be. reduced in accordance with the clearness ,of the
atmosphere, as little as half to one fifth of the indicated exposure
being sufficient.
   For medium plates, say about 150 H & D, the original exposure
time, given by the Diaphot, should be doubled, but if extra rapid
plates are used, say about 350-400 H & D, the indicated exposure
time should be halved.

 Medium plates about      Normal plates about        |        Rapid about    150H&D             225-250 H & D              "*.."40oH&D                                                                                            |
Imperial Sovereign   Imperial Special Rapid   Imperial Flashlight
Ilford Empress        Ilford Special Rapid       Ilford Zenith
Gem Medium     Gem Meteor               Ilford Monarch
Wellington Ordin.    Wellington Extra Speedy  Gem Salon
Marion             Wellington Anti Screen   Wellington Xtreme
     Instantaneous   Marion Brilliant        Marion Record
Barnet Ordinar-v      Barnet Special Rapid     Barnet Ultra Rapid
                    Barnet Self Screen       Barnet Super Speed
                 Kodak film

             af,iSn                               I\'-../,lKoN       I





II2074.50.228