Bertram standard User manual

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                   STAN DARD

THE PRECISION AUTOMATIC-ELECTRIC
        EXPOSURE METER
 (with optical measuring instrument
             incorporated.)
For all conditions of light and negative mdte-
rials  it  immediately gives you the correct
        exposures and lens openings
    for photography and cinematography

Ernst & Wilh. Bertram, Munich-Pasing
Faclory of pholo lechnlcal measuring inslrumenls
8.5r. 1/52 E                                                     Printed in Germany

The Standard is the  ind,ispensable adviser   f or  practical
photography and is so easily manipulated, its indications are so
reliable and exact, thdt errors or dcubts are absolutely impossible.
Measuring requires only two manipulations:
1. Pressing the button    the instrument is ready for measuring.                        -2. Adjusting of the measuring-tape with the indicated light value
   to the emulsion speed of film used    reading the exposure  and lens opening (takes about 5 secs.)-
The Standard-Meter is supplied in o n e model, but in two
executions, different only in calibration, but not in construction:
1. The ,,Standard"-Universal with table of exposure times and
   lens openings as shown on ,,between lens" shutters.
2. T,he ,,Standard"-Leica with exposures as shown on the Leica
   cdmera focal-plane shutter and the openings of the Leica lens.
Both models are supplied with the particulars required for
cinematography.
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Read carefully this pamphlet. Beside detailed directions yoLt
will find mdny things worth knowing for practical photography.
                   Contents.
 1. Detailed directions                      page 4-9
 2 Manipulation of the optical meter         page 10
 3. Color photography                 page  B
 4. Explanations about the scale of openings of
    Standa rd                       page 12
 5. Explanations abcut the scale of exposures of
    Standa rd                       page 13 6. Directions for evaluation of intermediate values pdge 14
 7. Sonre hints for the use of further advantaqes
   of the scales                             page    15
 B. General rules for electric.and optical measuring page   16
 9. Example, how to use the depth-of-focus table pdge   17
10. Use of Standard for cinematogiaphy     page     IY
11. Fina! remarks for special notice            page   90

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                 Detailed instructions for use
Hold the instrument flat on the palm of your left hand, with the
cover showing the trade-mark upwards. Press the knob, and the
cover will spring open; take care to catch the backward spring
with your right hand. (see Fig. 1 and 2).
First adjust the meter to the emulsion speed of the film used.
This is done by turning the knob (b) until the degree of sensrrive-
ness appears in the space (f). There is no need to repeat this
procedure so long as the same negdtive material is used.
Tlre red points on both sides of the scale of emulsion speed
present an enlargement of this scale down to 7/to DIN and up
to 25lro DlN. On instruments with Scheiner0 scales read 14 and
32 deoress.

On using a film with the above emulsion speed move the slot
of the covering slide by means of the knob (b) to the first                                l
speed number beside the red point being in question and adjust             I
the number of light value measured to this red point.                                                                                       I
                Adjustment of speed of film.
The speed of film is always given by the average value of a group of
speeds giving praclically the same result of exposure.
              Example   of  adjustment.:
On using   f ilms or plates of a speed ot 15 /10 DIN or 17 /10 DIN adjust in
both cases to 16/10 DlN.
When using the intermediate values you will observe the indications on
page 14. On instruments showing the Scheiner degrees the adjustment is
the same.

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After having adjusted the
                                    f ilm hold thespeed of
  I ight-electric photo-cel | (k)
incorporated in the cover
like the camera lens in
the direction of the object
t o be photographed. When
taking open air pictures,
be careful not to include
too much sky. The hood
allows no light to enterthe photo-cell than iscorresponding to   that
which enters the camera
lens, so that the light
falling on the object to
be photographed is accu-
rdtely measured. The                                      Fig. 2: The correct way of holding
                                          the meter in use.

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                  Evaluation of the light value.
                   By turning the small wheel (a) at the
e                       side edge of the instrument adjust the
  Lo                                                                          f igure read onto the scale of light  {,'E                       values (9, e) ,[yellow figures for photo,
 .D                     black ones for cinel exactly to the
 .9                            right speed of film (f). IFig. 1 and 2
  o.o                             light value ..,9" to 16lro DIN]. When the o -E,                             light value is fixed this way the rows
 o                   of stop figures' (c) and of exposure
 o                    times (d) are automatically adapted
-oJ                    to each other in such a manner that
  oco                         lor any exposure time the correspon-                        ding lens opening can be read. ._ Now
                    the measuring is   f inished: The data         Back View.Fig. 3                    given should be used for adjusting the
                            shutter and the diaphragm of thecamera.

                                                            ?

Minipulation of the Optical Meter.
       When the light is very poor
                       (i. e. indoor-, night-, moonlighi-photo-
           graphy, in churches, lravines elc.)
               and when the elec-
          tric photo element is not
        sensitive enough to  in-
                        f luence the needle, the
                                    ,used.       optical meter is
         Tilt the open instrument
        forward, place the lens
       (1)   f ixed in the base,
        close to your eye (Fig. 4)
           spectacles should not
      be removed   and direct       the instrument-  accurately
         to the object to be photo-
            Fig. 4. How to hold the instrument
         when working with the opt. meter.

www.butkus.us    grdphed. (ln order to prevent light from entering at the side,
    hold your right hand round the ground glass ,of the opticdl
    meter). After 5 seconds the highest numrber, readable without
     eye-strain, is the correct li,ght val'ue for this taking. In duloious
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-l   cdses use the intermediat,e number (e. g.when 2 is read with
   3 faintly appearing, take 2,5).
   You adjust the medsuring tape of the light values (e) in exactly
   the same manner as af ter electric measuring, placing the
    aforesaid figure to the emulsion speed, then read exposures
    and stops as dlready explained.                               Bu-lFui.O
     ln general the optical meter is not often used. But ,if by means
   of it you have succeeded in taking some beautiful pictures
    you will never want to dc wilhout  it.
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Thereby you will realise that it is the combination with the
optical meter that makes the electric exposure meter a perfect
adviser for any taking.
Explanations about thre scale of openings of the Standard
                                                                             dFor practical reasons the two rows of diaphragms most fre-
                                                                                                                                                                  flquently used have been put on the Universal Model of the
Standard. The difference between the apertures of the          ;rJ
unified diaphragms is about 30 %.   The scale of the instrument                                 -has been calibrated exdctly to the averdge value between both
openings; so the difference is halved. Therefore you may use
both stops read opposite to the exposure.
With regard to the intermediate exposures adjustable on the
Leica focal-plane-shutter the various diaphragms on the special
Leica Mcdel are given separately.
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www.butkus.us    Explanatlons about the scale of exposures of the standard
    ln connection with the re-gauging of srandar,d for color films
      it has been necessary to insert some unusual fractional expo-
    sure times on the measuring tape.,l   As long as we have to deal with black-and-white-photography,
                          t/s    the distance from    lo % sec. has been insignificant. The new
 I   color films, however, having a very narrow exposure margin,
    render it necessary to find the exdct exposure times at any
     rate. Therefore that distance is to be subdivided.
      lf then, on the measuring tape L/d sec. is followed by % sec.
    you may, when taking a black-and-white photograph, use % sec.
    or     in case o'f % sec. take 1 sec. as befor       -    For color photographs, however, the use of more accurate expo-
    sures is imperative.  lt is advisable to adapt the lens opening by
                                                                13

intermediate positions to shutter speeds of % or 1 sec.
on evaluation of intermediate light values eventually measured,
 there will result no fractionary stop values in any case.                                                       ?
      Directions for evalualion of intermediate light values                             I
Example: supposing the light value 12% given by the needle is
                                                                                                                                                                                 {to be evaluated for film speed 16/ro DlN. Adjust the sepdrating                                 a6/to                           ?line between 12 and 13 to      DlN. After this adjustment the
exposure times are to be read between the full figures of aper-
tures. In the example shown the openings between 9 and 12,5
or 8 and 11 are decisive for an exposure time ot tlro sec. On
the execution of this evaluation on the Leica Model the data
of exposure times and lens openings given by alternate colors
belong together. F,or light value 12% and exposure time 1/ao Sec.
you have to adjust the lens opening 11.
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    Lens apertures resulting 'by evaluation of intermediate vatues
   may easily be adjusted on the objectiVe by setting the mark
1.  between the fixed figures (Not to be used for punched dia-
    phragms).

     I     some hints for the use of further advantag€S, of the scates
                          of the Standard
17    ln the above way it is possible to evaluate exactly the interme-
    diate data of film speeds.
   Move the adjusting slide by means of the knob (b) in a po-
    sition that the sepdrating line between the two speed figures
    in question is bisecting the slot of the slide.    E. g. tsln DIN                                                 -     is adjusted, if the separating line between 1slro                                           and 16lro DIN is
    bisecting the slot of the slide.   Then the evaluation is carried                                  -    out as usual; the whole light values                                   are put exactly opposite to
    the slot, whereas the intermediate values are corresponding to
                                                               15

the separating rine between the limiting figures and the line
 between the two speed figures in question. ln every case the
 exposure times and the lens apertures standing opposite to
 each other are to be used together on practising some
 evaluations you will see that the Standard is able to answer        jI
                                                                                                                                                    I every question concerning exposures and apertures.
       Generar rures for erectricar and opticar measuring                               T
 1. when taking photographs with artificial light only panchro-
   matic material is to be used. Add one light vaire to the.  figure reod. when using orthochromatic negative mdterial,
   take one light value less than measured.   The numbers 1,5;   2,5; and 3,5 are also whole numbers.    -
 2. when using double extension ,of the bellows in connection
   with back or front lens, use two light values less than the   figure read.
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j# 5. When using yellow filters adjust as follows:
             2-3 times, 1 light value less,
           .      4-5 times, 2 light values less,
             6-8 times, 3 light values less.
   In order to extend the eff ectiveness of the instrument for
   additional help a depth-of-focus table (i) for the focal lengths
  most frequently used is attached below the measuring scales.
  According to the depth-of-focus desired the correct aperture
   can be read at once.
          Example: The use of the depth-of-focus table
  A group to be photographed, the lirst row being 12 !ss1 from the camera
    (10 feet deep) and the back row 22 teet. To get a clear picture extending
   over the entire group, a certain distance focussing as well as adjustment
   of the lens opening is essential.
   The reading off of the Jocal distance, as w6ll of the correct aperture,  is
   {ound as follows:
                                                                  17

Looking down the column ,,sharp" in the region of 12-30 for the above-
 mentioned photograph, we read in the column,,focussing,, the focal distance
 of lhe cdmera (15 feet). Now turn  f rom the aperture observed in the first
 upright column, horizontally as far as the point of intersection of both columns
 The reading is: for 5 cm (:  2,,)    .  ll4.S; for 7,5 cm (:   J,,)     t16.3 etc.
The exposure figure corresponding to this aperture is read on the instru-
ment in the usual wdy.Smaller apertures may always be used, if  the
depth of clearness is favorable; wider openings, however, lessen the
extension of the deoth.
 ,,Circle of diffusion" means the unsharpness of a dot admissible for enlar.genrents         of this size,                       looked                                from                               at                                     normal                                                  distance                                                                in order                                                                 to get                          -                                                                   -pictures           sufficiently                   sharp.                           For,                            the                                   smaller                                       the                                                   original                                                                                     the                                                      negative                                                                                 is,
more you must observe its sharpness, because, in general, bigger enlar.
gements are made from such than from negatives of a larger size.
For better understanding of all important items of theory and practice of
photography we advise every- beginner to buy a manual of amateur-photo.
graphy. Such books are to be had at low costs with.r! photographic stores.
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'        Use of Standard for Cinematographywww.butkus.us
The' manipulation of standard for cinematography is the same
as for ordinary photography, the only difference being that,
after the black light value figure has been adjusted, it is not
the exposure times which are opposite t,o the scales of aper-
tures, but the  ,,f rames" (numbers indicating the change of
pictures per second). Therefore the correct lens opening
corresponding to every single frame can be read immediately.
   Notice that the two inner scales of frames and apertures
apply to each other, and the two outer scales likewise
correspond.                          &,4k *;v
on the Leica Model red applies to red and black to black.
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