Sears RANGER Exposure Meter User manual

RANCER



      PHOTO-ELECTRIC

  EXPOSURE METER
      No. 6434
                            Digitally signed by
                     mike butkus
                     DN: cn=mike butkus,mike      o=orphancameras,ou=29,

                       c=USbutkus email=mike@butkus.org,Date:                             2016.12.18
                        20:22:09 -05'00'


  SEARS, ROEBUCK AND CO.

INSTRUCTIONS FOR
       OPERATING THE
        SEARS RANSER
      PHOTO ELECTRIC
       EXPOSURE METER

            Foreword
    It  is simple to operate a Sears Ranger
exposure meter. Although designed to com-
bine precision with ease in operation,  it  is a
precision irrstrument containing minute. ac-
curately balanced parts. Ilowever,  it requires
no more than normal care to insure its ren-
dering accurate and faithful  service.
  Treat your exposure meter as you would
a fine watch. Your exposure meter, like your
watch, will  give longer service  if you will
protect  it  fronr sudden jars, extreme vibra-
 tions and excessive dampness or heat.
   Instruction is a guide to experience, not a
substitute for   it.  Give yourself the benefit
of  actual practice. This bcoklet will  then
serve its purpose as an aid in the develop-
ment of good, practical judgment in the use
of your Ranger exposure meter.
 Four Foclors of Correcl Exposure
  Among the factors that contribute to theproper exposure of photographic  film, the fol-
lowing are of special importance:
                               I

butkus.us
    1. Intensity of light on the subject    2. Sensitivity of the film    3. Diaphragm opening    4. Time of exposure (shutter speed)
   Correct exposure requires the predise quan-
titative correlation of these factors. The
 photoelectric exposure meter is a scientifically
designed instrriment for achieving this cot-
relation.
    How lhe Meler tndicoles
            Light Intensily
  The Sears Ranger photoelectric exl)osure
meter consists of three major parts; a photo-electric cell; a highly sensitive electrical in-
dicating instrument; ancl a set of calculatordirls. The photoelectric  cell has the property
of generating electrical current unilef  th-einfluenceinfluence ofof lightlight impingingimpinging uponupon itsits surface.surface.
ThisThis currentcurrent entersenters thethe inclicatineinclicatine instrumenti
andanrl causescauses aa deflectioncletlectlon ofot tletlle ooirinter.Dolnter. TheIhe
exterrt of the pointer deflectiorr bears a fixerl
ancl precise relationshio to the inter-rsity of
light falling upon the photoelectric  cell. The
lninter deflection is, therefore, a measure oflight intensity.
         filn Exposure Index
  Photographic  films differ in respect to their
sensitivity to light. Light of the same inten-
sity falling on various kinds of film will pro-
duce different photographic  effects due to the
inherent characteristics of the film and thelight to which  it is exposed. These character-
             (Continued  inside)
                     2

istics. therefore. must be taken into consider-
ation in determining the correct exposure.
  Films of different light sensitivity are as-siened different expostlre index numbers.
Divli,{ht and artificial light affect the filmdiffer6ntlv. Each film, therefore, has an
exoosure-index for davlicht and another for
 trrirgsten light (as the- most frequently used
artificial illumination).
     Obfoining the Light Yolue
  Whether the exposure meter should be
held at the camera lnsition or close to thesubject; whether  it should be directed at the
subl'ect or at the source of light, will depend
upoh the kind and amount of illumination  atrd
upon the nature of tlre subject.
  Oirtcloors, where the subject is not  sur-
rounded by  large areas of  highlights  or
shadows, hold the exposure meter at or near
the camera and point  it  directly at the sub-
iect.  'l'he exposure time so determined will
ire c:rlled "the exposure at camera position."
    If  the subject is placed against a bright
background, the tneter sho'.rld be held about
r  foot away from the subject, taking care
to see that the shadow cast by the meter
itself does not influence the actual exposure.
If  srrch close approach to the subject is not
practicable, deterrnine the "exposrtre at camera
irosition" and aCjust this exposure according
to tlre following:
     1. Scenes which require one-half the
        "exposure" at camera Position:

butkus.ussurrounded        (a) Subject of chief interest        by heavy shadows, as in  Photo-           gr4phs taken through a doorway         and in which the doorway is  tn-
             cluded.
        (b) Subject of chief interest is part of
              large highlight area, as for example,
          snow scenes in which detail of the
          snow itself is desired.
      2. Scenes which require twice the "ex-
          l)osure at camera position."
        (a) Subject of chief interest surrounded
       I     by large areas of highlights, as a
            ship on a brightly-reflecting body of
             water, or a relatively dark object in
        a snow-covered landscape.
        (b) Distant landscapes which usually
            present mist or haze that reduces
           the reflected rays.
   For indoor, daylight photography with
  amole illr-rmination. use the same orocedure
  as'for outdoor photography. Undei certain  conditions, however, the light may be so
.  poor that the exposure meter does not clearly  register at the camera position. In  that   caie, hold the meter close io the subject and  point it at the window or doorway through  which the subiect receives most of the  il-  lumination. Tlie meter in this position  will
   indicate the intensity of light incident on the
   subject.
      ' The light reflected by the subject will be
  of much lower intensity than the light inci-  dent upon it and will, therefore, require much
  longer exposure to produce the desired photo-
   graphic effect. Determine the exposure time
                         4

corresponding to the incident light and multi'
ply by 10 to obtain the correct exposure'
      photogranhinc                                     light, aim              bv artificial  In                      For portraiture,    meterthe           at -the -subJect.hold the meter about a foot away from thesubiect, If  the entire fisure is to be in-cluded in the picture, holil tlte meter abottt
three feet from the subject.
  Photosranhic emulsions lteve a higher speed
in davlicht than in tungsltrr light, becausedavlicirt contains a higher I'ercentage of thebluev-iolet actinic light to which plrotographic
emulsions are most sensitive. Tlrerefore. in
usinc the calculator for artifici;rl illuminatiorr,..tr,a"-bet to apl,ly the exl,osttt e irrdex for"Tttngsten" til"                  w(nu|'                               tor,o"
 The calculator "",""on the Ranger exposuremeter is comnosed of two movable dials. One
dial is used io set llte exposure index of thefilm in use, while tlre larger dial in turn isrotated to correspond vgith tlte light valueindicated by the rneter. F values are indicated
on one di:ti and shutter speeds on tlre other.Therefore, the calculator is a mechanical
means for transposing  light values to camera
settings.
  How lo Operole the Colculofor
  After obtaining the light value from- thescene, as describdd in seciion 4, the calculator
should be set as follows:
    1. Rotate the inner dial until the arrow     on the window is set to the index

number of the filmbutkus.usin use. This
      window is marked "exposure index."
    A list of film index numbers is in-
      cluded with the Ranger exposure
        meter.
    2. Rotate the outer dial so that the red       arrow is set opposite the light value
        indicated by the meter.
    3. The correct F stop and shutter speed
        combinations are then shown on the
         sides of the two dials opposite from
        the red arrow.
EXAMPLE: IJsing a film having a speed    of 100, the inner dial is rotated until
    the arrow at the exoosrrre index window
     is opposite-value 100. Let us assume that the      liehd       obtained from the scene was
    9. Rotate the outer dial such, that the   red arrow is opposite the line leading
     to 9 on the meter scale. On the opposite
     side of the dial, correct camera settings
     will then be found. i.e. 1/50 of a second    at F 8-1/25 of a secotrd at F  Il  artd
    so forth.
  In the event that the meter does not show
specific 6lm speeds, shutter speeds, and lens
stops you are using or have on your camera,
the nearest factor should be used.
 Besl Time-Dicphrogm Combinolion
 Which of the foregoing combinations of
exposure time and diaphragm opening should
be employed? Decision on this point will rest
largely on certain features of the sirbject
being photographed.
                       6

Selection of one of the indicated combina-
tions may be made either because some par-
ticular diaohraem oDenins or certain shutter
speed is required  fo-r photographing  the sub-ject effectively. For example, the desired
depth of field might determine the optimumdiaphragm opening; or the motion of  thesubiect might make a certain shutter speedpreferable. In this connection, the followirrg
iimple rules may be observed:
     (a) \4'ith  i  given distance between(a      camera and subject,-    and with a(a      given lens, the  smaller the dia-
(a      phragm opening, the greater will
(a)     be the depth of field.     (b) The faster the motion of the sub-(b)      ject, the less should be the ex-         posure time (faster the shutter(b)       speed).
  The time-diaphragm combinations on thecalculator are so numerolls that not all of
them can be directly applied to your camera.
The calculator dials mry show some f-values
and exposures to which your camera cannot
be set. If you wish to use these combina-
tions, you can easily approximate tbem by
using the next greater exposure time, or the
next snraller f-value.
   Exposure for Mollon Piclure
            Gameroc
  Most amateur motion picture-second cameras havea shutter speed of 1,/30        at 16 frames
per second. The Ranger exposure meter has
a red dot on the shutter speed scale repre-
                       7

1'*l
and the sensitivity of the film. All three con-ditions must be known to cletermine the
annronriate filter factor. The factor usuallyuiimjrrentlv marked on the filter-mount  is,      t,
iherefore, fikely to be inaccurate for differerrtlilms and untler varying conditiolrs.                 {
 When using filters, consult a reliable table
for the appropriate  filter factor for th,e specific
ftlrn anrl-filter you are using. Then determine
rlre exlrosure f6r unfiltered light in the usual
nrannei and multiply by the filter factor to
obtain the exposure for the filtered light.
   It must be remembered that filter factor
tables are not to be regarded as being com'
pletely accurate. They will serve, ltowever, as
i  roueh guide upon which to base initial
experience.
                                        by                                 reading                             direct                secure             to  Do not                a          try                                                    L                                the meter!                               cell                over                     theholdins                filter        the                           ofThis does not result in the correct exposure
for various technical reasons which need notbe gone into at this point. Arlhere to thefactor metlrod of compensating for filters in
exposure.                                                                                                     t'
        Zero Adiuslmenl
 To check the meter for its proper zerosettins. hold vour hand over the cell window  fl-lso as"[o cut off all light. The pointer should
now point to the lowest mark on the scale,in other words,  it should indicate zero lightintensity. If   it does not register zero, turnthe zero set screw in the center of the dial
until the oointer rloes register zero. Check the
meter at iegular intervals.
               9 (END)