Sekonic Universal Exposure Meter User manual

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                          Contents.:
The principle of the electric exposure meter
The characteristics of light and human eves
The Sekonic Universal Electric Exposure Meter               .................. B
The specific characters of the sekonic Electric Exposure Meter......... b
The explanation of the mechanis#                                            ...,.. 6
The photograph of the L-II ,fype Blectric Exposure Meter ............... z
How to use the L-II Type Electric Exposure Meter              ............ g
How to take pictures ..........                                             ..,.............14
'fhe special use of the meter                                            ...............16
The measurement v!of thelrru  v^lrsr'rrir,yextremely ruwlow rllumlnatlonillumination                  .........16
Photographing by the artificial light                                  ...............rR.......18
In the case whenbcolor films are used...                           .,.............24
The change of shutter speed and f_stop                            ...............2b

-2-How to use the meter in the movie photography """""""""""""""26  f
About tlre special photographing"""'                            ""'28
Corrections in the use of the filter                          """""30
How to use the illumination meter
1'he technical explanation of the Sekonic Electric Exposure Meter """32
'l'he liglrt sensitivity of various films ""                    """"""34
Attached table-(1) Comparative talbe of the light sensitivity """"""36
 e,,u"t"O tablS (3) The rnultiplier for the filter ""r""r'r"r"""""""""$$

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          Sekonic Universal Exposure Meter.
         rype L-II Reflected Light Type
         Electric Exposure Meter.
     ' The principle of the electric expoBure meter.
  t'he electric exposure meter is one of the instrument for measuring
light quantity best utilizing the most conspicuous physical property of
the photo-cell which was discovered about twenty years ago.
 When light is applied to a photo-cell an extremely minute electric
current is produced between the  ( * ) pole and the  ( - ) pole of the cell,
and the produced electric current varies according to the change of
light quantity.
  Therefore, an electric instrurnent which is assembled to measure the
liglrt quantity by measuring the electric current and answer speedily

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    the tirne and f-stop by setting the pointed reading to the light sensit-
     lvity of the filrn (see the last page) is named the electric exposure
['    meter.I'     Accordingly, an electric exposure meter may be employed as an
g    illumination meter.r"    The L-II 'fype meter which is manufactured by our company has
    readings from 1 Lux to 16,000 Lux and those readings are adjustedfl*t    with the logarithmic scale.
f,     The characteristics of light and human eyes.
     Human eyes adjust to the light quantity conducted to the nervousil
ffi;  system by the natural regulating action of the iris according to the
ft    natural light strength.
ft     Therefore, as you know very well, we feel dazzled when we enter
     into a house from the outside exposed to the intense sun light, losing
    our eye-sight for a moment.

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 'eonversely, when we step out of a dark room into a room admitting
sun shine, the same phenomenon as stated above is felt and we gome-
times feel the temporary Ioss of eye-sight.
  Thus, hurnan eyes are greatly governed by the external light' and it
is our natural conclusion that in the case when the light quantity bears
great importance, such as in photographing, the human eyes are the
rnost unreliable.
  Electric exposure meters are used solely for measurement in pho-
tographing and especially they have become necessary since the
development of natural color photography.
   Sekonie Eleetrie Exposure Meter.
  One who has obtained a camera finds it most difficult to determine
the time and  f -stop which are the most important for photographing
and which require years of practice before one becomes an expert.

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  Also, even professional photogaphers who take the responsibility of
perfoming reliable photographing have to exercise rather keen percep-
tion in order to always make god pictures of the subjects which change
in every way.
  The Sekonic Electric Exposure Meter is the scientific light quantity
measuring instrument which can be recommended with  absolute
confidence in such a @se.
   Its specific characteristics are illustrated as follows:
   The specific characters of Sekonie -Electric Exposure Meter.
 ( I )  This mechanism allows scientif ic and free choice.
  This exposure meter is the reflected light type electric exposure
meter to which the latest discovered principles are applied and every
subject c€ln be taken by it, being many times more reliable than tho
human eyes.
 (2)   Its use is very simPle.



                 -*- -*  i*-- *

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                                                           -5-
 Bv thie eleitric exposure meter various multiplie'rs and the relation
of shutter to f-stop are visible at a glance in one movement of adjusting
the reading pointecl by the meter with the calculating disk when the
meter is faced toward the subject.
( 3 )  Its photo-cell is highly sensitive.
 The photo-cell which is installed in this meter is hiehly sensitive'
being manufactured by our company with special care and it can be
used in the night as well as in the daytime.
  Especially the L-II Universal Type is manufactured as an all around
type.
( 4 ) The color sensitivity curve is adjusted with the visual sensitivity
    curve.
  Therefore, this meter is of great necessity in the case of natural
color photography. Also, the meter can be used in the sun light, electric
light etc., which are either natural or artificiial light.

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     l)  Explanation of the meehanisrn.
 The mechanism is illustrated by the indicating lines shown in thc
diagram of L-II.
    I ) Plastic body                      10) ASA light sensitivity
  2 ) Pointer                             reading
  3 ) 4 ) Light receiving plane of     11) F-stop reading
       the photo-cell                 12) Red arrow rnark
  5 ) High illurnination reading        13) Filter multiplier
  6 ) Low illumination reading     A A scaie
  7 ) Multifilter (Multiplier)       B  B sqrle
  g ) Illumination reading         c C scale
  9 ) Time reading

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 ( 5 ) The ASA light sensitivity is shown on our Electric Exposure
Meter, but it can also be convertel to DIN and weston light sensitivity
very easily.
( 6 ) The f-stop and shutter speed of the movie projector can be
determined very simply.
(7 )  In its design this meter is ahead of all foreign made meters.
( 8 )  This is a high precision instrument and its coeff icients are exact.
( I ) A strap is attached to the meter so that it may be handled
conveniently.
(10) Being encased in a beautiful tnx, rnanufactured of bakelite, it win
rtand against stronger shock than other like products.                                                                                                                       \"

I|I                                      -e-                                                                  the  I  'rn" above names will be explained in the explanation of
  I measuring method in the following.
 I    Uotn to use the L-II Type Electric Exposure Meter'
 |  < t  ,, The piastic body is a beautiful black one, being full polished and                                   and its pointer  ( 2 ) is clearly | ,to,rt. 'fhe body contains the meter in it
   visible inside the window.  ( 3 ) At the back of the multiplier (which
   serves also as a cover) on the light receiving plane of the photo-cell
   and the complex prisrnatic lens ( 4 ) are installed, and the reading diak
   having a double scale is used for both the low illumination  ( 5 ) and for
   the hieh illumination ( 6 ).
    'Ihe calculating disk A, B and C are manufactured eo that the f-stop
  and trme may be chosen freely. on the back a screw for zero point
   regulation is attachefl being mechanically connected with the meter'
       If you have a L-II Tvpe Sekonie Exposure Meter hold its bodv in
   yorrr left hanfl and your pose should be such that allows the free

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movement of the filter and the calculating disk with your right hand.
The filter is manufactured so that it may spring up automatically when
a push button on the lower part of the body is lighfly pushed.
  As illustrated the L-II Type Electric Exposure Meter recieves light                  tfrom the front as illustrated by the arrow and it should be held ho-       I
fizontaly so that the pointer on the reading disk for the illumination
should point zero read,ing on the disk when no light cones into the
meter. (In this case, to cut off the light your hand should cover the
meter or the meter should face toward a dark place. )
   If the pointer does not point zero-reading, it must be regulated
beforehand by rotating the screw with a driver either to the right or
to the left so that it may point zero always.
 when the regulation is finished we will proceed to the next step.
 when you take pictures of persons or of scenery with the L-II Type
Sekonic Electric Exposure Meter, the light receiving plane of the photo-

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cell ehould be faced toward the subject.'.-;         trri'   Azh.
  Then, let the reflected light frorn the subject fall on the photo-cell to
move the pointer ( 2 ) on the illunrination meter. The reading of the
illumination meter consists of a double reading ( 6 ) scale and  ( 5 )
scale, the  ( 6 ) scale being the reading for the low illumination from
                                                                          16,000O to 500 Lux and ( 5 ) scale for the high itlumination from 260 to
Lux.
 when using the low illumination reading ( 6 ), you have to take off
the front multifilter (multiplier) from the Iower hook, and whqn you
use the high illurnination reading ou have to fix the multifilter (7 )
by pushing it downward.
  Next, an explanation will be given as to the use of the dial slide rule.
the slide rule consists of three calculating disks: C,ll(urt,at
 A scale  The illumination reading and T (shutter speed) reading;
 B scale  ASA speed (light sensitivity of film) and f-stop reading;

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-12-C scale  ASA pointing window and filter multiplier reading,'J4  !;"'
  Find oui the light sensitivity of the film in the red window of the C
scale from arnong the ASA readings on the B scale.
  For instance,  if the light sensitivity of your film is ASA b0, rotate
the C scale carefully to the right or left so that you may find it at
the exact center of the red window.
  Also, the midway points between ASA 50-ASA 2b will be shown as
40 snd 32 respectively.
  Next, an example will be given in the case when the illumination
value is 65 according to the pointed illumination reading when the
picture is being taken.
 The pointed illumination reading will be adjusted, by rotating the
disk carefullyr.'with the same nurnerical value indicated by the red
arrow on the C scale.
  'fhen choose the best f and r you desire from among the num,efcal

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                                                                                                                                                                                                                            n
                                  ^13                          I
 figures of the f-stop and T on the exact opposite side.                                                  tfl
                                                                                                                                                                                       E  when you take pictures by using a  f ilter, if the multiplier of the filter
 is known, the f and r you desire wiil be c'rculated very simply as
 above by adjusting the illurnination you now have with the position of
 the multiplier line of the filter, not u'ith the red mark on the C scale.
 (of course the liglit sensitivity of ASA is left untouched.)
  The exposure calculation in the case of  r,-II Type Electric Exposure              n
Meter can be made as above, but the carculated varrles of f and r  will       t
be found with some discrepancies respectivelv.                                                                         I
  Having studied the cause of the above discrepancies and the defects
of the other makers' slide rures, we calcurated out the most precise and
reasonable method with which the scales are graduated.
  For instance, we often find the f-stop between 4 and B. b when the
shutter speed is L125. In this case, adopt the f-stop B. b as the nearest
and I stop smaller numerical value to the f-stop you found, in view of

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giving longer expobure  if poSsible, ard set it to your camet'a.
  However, in the strict sense, find out the f-stop which corresponds
to the T (time)r and the f-opening of your camera rnight be adjusted
somewhat.
   2) Ifow to take Pietures.
I )  Set your meter by rotating B dial carefully that you may find the
numerical value 50 which is among the ASA light sensitivity on tfle B
scale, in the window of the red arrow mark of the C scale'
  While the film ASA 50 is used this may be kept set in that condition.
  Next we will explain about photographing when the subject lies itt
such a place as a room where scanty light is admitted'
  First, we will describe the film you use.
  Every film has its own fixed light sensitivity, such as sakura Pan
ASA 40 and Eastrnan XX 100 etc. Let us explain the case when we use

a film with the light sensitivity ASA b0.              -15_
 2) Let us explain the portrait photographing.
  First, the reflected ligtrt from the subject is measured B0cm-b0cm
 off the subject. Then, let us suppose that the place where the needle
on the illumlnation rneter points be 6b Lux. 'fhe pointecl figure 6b will
be found among the nr:rnerical figures under the "LIGHT" on the diar,
and be acljusted *'ith the point indicated bv the red arrow.
  'fhen you may choose a combination of f-stop and  'r' you desire most
from a series of combination of f with time found on the A and B
scale on exact opposite side.
   If you have a camera with a lens f 4.5 the tirne corresponds ta t 4.5
is 't ll25 also t.ha.t corresponds to f 6.3 is T U10 second; and you will
f ind a series of combinatiorr of f with time.
3)  'I'hus, you will be able to obtain your desired shutter spee<i carcura
tion. And then, when you use the electric exposure meter, the back

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-15-light (other than the necessary light)  will beconre the most probable
cause to introduce errors in catching the most exact light intensity, and
so you will take every possible consideration to prevent this err:ors,
(for example, you will cover the meter with your hand that unneces-
sary light rnay not corne into your rneter.)
  At outdoor photographing, you may measure the light intensity by
directing vour meter to the scene, but in the case when you have verv
clear sky, hold your rneter in somewhat inclined position that the clear
sky rnay not affect the meter.
   The special use of the meter.                                                                             f t*k  -3 . v,
4)  Extrernely low illumination measurement.
 The L II Type Electric Exposure l4eter can be used in the night
with low illumination. It can be used with success in most cases, but if
you use the follqwing pethod for the photographing under the low illu-

_17_
mination,  it  is possible to measure the illurnination up to ten times
Iorver than the lowest illuminaticn on the reatling of the meter.
  In the case when it is impossibre by the common method f:rcing the
exposure meter torvard the subject, to obtain the lower reading than 4
Lux by the reflected light, an exact reading can not be obtainable
accuratly.
  In that case, the exposure for the principal light is deterrnined by
the ordinar:y operation in facing the light receiving part of the exposure
meter toward the direction where the prin,:ipal light corles froru. For
instance, let  u,'j suppose that the condition under which we take a
picture of a person who is sitting at a place two rneters from the
position u,here an electric light (100 watts) is lighted.
  In this case, if the field of picture is so dark that the reflected light
frorrr the subject lighted by the electric light is naturaliy ulobtainable,
the principal Iight is measured by facing the L-II Type Electric Bxposulg

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Meter-     toward the electric bulb from the poeition of the person.
  Let us suppose that the ureasured illumination be 65 Lux. Rotating
carefuliy A scale (8) we adjust the measured illumination 65 with the
arrow mark that indicates ASA 50 as stated above, then in the case
when f is 2.8 we lvill find T 1/50 second as th.e time corresponds to it.
 And then,  'f (1/50) is multiplied l;y 10 the answer will be
              tl50xlO:7/5      that is,  1/5 sccond
  In this case you rnay deternrine the proper exposure as 1/5 second
with f-stop 2.8.
5)  Photosraphins by artificial  light.
  Sotnetimes we come across an occasion when photographing  inside
a room is performed uuder the principal light which is the artificial
light produced by dornestic electric bulbs or photographing r:lectric
bulbs.
 Ae the artificial light differs from the sun light in the distribution

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             I                                                    19-
   of the spe.ctrum, the exposure is recommended to be about 40/" rnore
   than the calculated one.
     of course the light sensitivity of the film either in'the sun light
   or the artificial light is specifie,d by respective film manufacturing
   company'youmayusethefigurethatindicatesthelightsensitivity.                                                                                          f ilm has ASA 100 as it light sensitivity     For instance, Ansco ultra speed
    in the sun light and ASA 64 in thc tungsten light, trecause in technical
    terrns the color sensitivity of thc iight produced by the electric bulbs
    differs from that of the sun light'
   6) Sometimc.s you have to take pictures under special conitions' Either
   theexposureofone_halfofthestandardisneededordoubletime
    exposure is needed' You can study it frorn the following table'