Light meters
DeJur Photoelectric Exposure Meters User manual
User manual for DeJur Photoelectric Exposure Meters. 14 pages in English. Read the original PDF, download or print a copy without registration.
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- Brand
- Dejur
- Model / document
- DeJur Photoelectric Exposure Meters
- Document type
- User manual
- Language
- English
- Pages
- 14
- File size
- 1.6 MB
- Category
- Light meters
- Document date
- Not specified in catalog
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Page 1 · Read text
IeJ[|n
"Aulocrilic" Model 50-A Exposure
Meter "Aulocritic" Model 50-A "Cane" PHOTOETECTRIC
Exposure Meter
"Versqtile l" (2t/ax3volEnlorger EXPOSUREMETERS
"Versqtile ll" (3Vtx AVolEnlqrger
"Versotile Professionql" (4 x 5) En-
lorger
"DeJ ut 8" Motion Picture Cqmerq oMw "DeJur 8" Motion Picture ProiectorView original page 1Page 2 · Read text
It is simple to operate a f).,Jur e\l)osure meter. lt was
designed to comlline Jlrecision rrtllr rd:-e ilt olreraliolr. Al-
though it is a precision instnrlrrrnl eorrtailring minute,
accurately llalanced parts. it rc'rlrttr..q 1r() nr're lltan n()r-
mal care to insure its rendering ar'('rrrate arrrl faitlrful
service. The movements built Inlo l)';sr ntrt(:rs are inDe-JUR-AMSCOCORPORATIONaeeordanee with the AS,\ sper:ihcatr'n5, olfrrirrg vou a ]ONG ISTAND CITY I meter that conforms to the mosl nr,,rlern develolrrnr[ts.
NEW YORK Treat your exposure meter as vnu wr)ulo a filre wateh.
Your exposure meter, like your rratch, will give hrnger
serviee if you will protect it fr.,6 jar*. extreme "url,l,.n
vibrations and excessive dampn"..,r or hrat. 51,ecial skill
P'inted in U.S A. is required to repair a photoelectric exposure nreter, andView original page 2Page 5 · Read text
5. How to Operate the Calculator3. Film Erposure Index
Photographic films differ in respect to their sensitivity The usual problem in exposing g fi!- is to deterrrine exposu-re the and opening diaphragm rhe lens li-"to light. Light intensity of the same falling on various to the given and film to that tp""d ( shutter ) appropiiate will producekinds photographic of film effects different
due to the inherent characteristics of the film and the conditions of illumination.
lieht to rrhich it is exposed. First, find the exposure index number of the filn in
Films of different light sensitivity are assigned dif - the list of exposur" ittd"* numbers-; then align tb" ex-
ferent exposure index numbers. Daylight and artificial ;";"t. inde* bn one dial of the calculator with the di-
light affect the 6lm differently. Each film, therefore, has iirio" o" the other dial corresponding to the light in'
an exposure index for daylight and another for tungsten tensity indicated by the exposure meter.
light (as the most frequently used artificial illumination ). The resulting alignment of the other two scales on the
calculator will"then' shorv the desirable combinations of
4. Tlrc Calculntor . exposure time and lens diaphragm opening.
The calculator on the DeJur exposure meter is com- In the event that the meter fails to show the specificposed of a stationary and a movable dial. Two sets of film speed, shutter speed or lens stop YQu-shoulda-r9using or. havegraduated divisions are etched on each dial in such posi- on your camera, the nearest factol be used. Or,tion that the divisions on the two dials can be aligne.l. itt.'Utorf between any trvo figures can be used, and IThus the divisions representing the light intensity on one reading easily secured.dial can be aligned with the divisions representing the
exposure index on the other dial. Note the two lines etched To illustrate, the film speed index of I is not shown
on the scale glass These can be set over the speed number on thttt"l", Y€t you are working with-q film of this speod'
of the film in use by rotating the glass with the fingers. ili;;;it;;t ih. rp"r" between 6 and 12 and the lens and
shuttei speed tt"dittgt will be correct for a film speed The f-values and exposure times represented by scales of 8.of graduations on the two dials can be similarly aligned.
Thereby the calculator provides a mechanical means for The same holds true with shutter speeds and lens dia-
rccurate correlation of the four factors of film exposure phragms. Interpolation can -easily pto"ide the correct ex'
previously mentioned. ;;#t ior all th.ttt"-t speeds, film speeds and lens stops
The colored dot on the scale glass is for color as [i-.riting the diaphragm setting on the lens between t$'o stop$dcecribed in Section 8.
1View original page 5Page 6 · Read text
The reason some numbers are absent on the scaleg is for f.values and exposures to which your c1llrcra cannot rF
the sske of greater legibility of the figures. It is felt that s€t If you wish'to usc thesc combination+ you ctn earily
Gasc of reading is to be preferred to small, numerous and approximate them by using_ thc ncrt srGoSer exponrtt
hard-to-read scales. time, or the nert smaller f'value.
6. Best Tim.e-Diaphragtn Combination
Which of the foregoing eombinations of exposure time
and diaphragm opening should be employed ? Decision
on this point will rest largely on certain features of the
subject being photographed"
Selection of one of the indicated combinations may be
made either because some particular diaphragm opening
or 8 certain shutter speed is required for photographing
qhg subjegt efrectively. For example, the desired deprh ol' HONEYCOMB LIGHT BAFFLTfield might deternrine the optimum diaphragm opening; The correct an(le of li$ht'acceptane lot
or the motion of the subject might make a certain shutter averape oarnetas and lenJes is redulated by
spged preferable. ln this connection, the lollowing simple -""rri ol a "honeycomb" Iieht baffie located photoelecttic oi the sensiiive 1ront inrules may be observed: direcilv 5O'A MODEL AUTOCRITIC the cell oi
a) \[ith a given distance between camera and subject, and AUTOCRITIC MODEL iO'A'CINE
and with a given lens, the smaller the diaphragm open- rneters.
hg, the greater will be the depth of field.
b) The faster the motion of the subject, the less should 7. How to Hold the Exposureffieter
be the exposure time ( faster the shutrer speed ) . See table
of shutter speeds on page 23. Whether the exposure meter should bc held 8t thc
camera position ot tlo." to the subject; whether it should
The timediaphragp combinations on the calculator are be direcied at the subject or at the source of light" will
!o numorous that not all of them can be directly applied depind upon the kind and amount of illumination and
to your camera. The calculator dials may show some upon the nature of the subject.View original page 6Page 7 · Read text
In outdoor, daylight photography in which the srrbject b ) Distant landscapes whicb usually present mist
is not surrounded by large areas of highlights or shadstvs, or haze thet reduces the reflected rays.
hold the exposure meter at or near the camera and point
it directly at the subject. The exposure time so determined For indoor, daylisht photography with ample illumine-
will be called "the exposure at camera position." tion, use the same pto"Ldure as for outdoor photography' Under certain however, the light may be so
If the subject is placed against a bright background, the poor that the exposure"onditiottt, meter does not clearly register
meter should be held about a foot a\vay from the subject, at the camera position. In that case, hold the meter close
taking care to see that the shadow cast by the meter to the subject and point it at the window or doorway
itself does not influence the actual exposure. lf such close through *liith the subject receives most of the illumina-
approach to the subject is not practicable, determine the tion. The meter in this position will indicate the in'
"exposure at camera position" and adjust this exposure rensity of light incident on the subject.
according to the following: The light reflected by the subject will be of much lorver
l. Scenes which require one-half the "exposure at irrtensity than the light incident upon it and will, there-
camera position": fore, require much Iottg.t exposure to produce the de'
a ) Subject of chief interest surrounded by heavy siretl photographic effect. Determine the exposure time
shadows, as in photographs taken through a door- corresponding io the incident light and m ultiply by I0 to
way and in which the doorway is included. <llrtain tlte correct exPosure.
b ) Subject of chief interest is part of large highlight In phutographing by artificial light, aim the meter at
area, as for example, snow scenes in which detail the subje.tl Fo. pottraiture, ttota the meter about a foot
of the snow itself is desired. away f.L,n the slbject. If the entire figure is to be included
2. Scenes which requirc twice the "exposure at camera in the picture, Itoid the meter about three feet from the
position": subject.
a ) Subject of chief interest surrounded by large Photographic emulsions have a higher speed in daylight
areas of highlights, as a ship on a brightly- than in tungsten light, because daylight contains a higher
reflecting body of water, or a relatively dark percentage of the blue-violet actinic light to- which pho'
object in a snow-covered landseape. iogr"phii emulsions are most sensitive. Therefore, in using
l 0 l tView original page 7Page 8 · Read text
the calculator for artificial illumination, remember trlotion picture exposure can be easily calculgtcd by
apply the exposure index for "Tungsten" light. means of the other DeJur exposure meters as well U
your lneter has a calculator which indicates exposnrre in
seconds and fractions of a second, find the normal shutter
8. Exposure lo, Color speed of your camera at 16 frames per second. Most ama-
The Autocritic 50-A is designed particularly for color teur motion picture cameras have a shutter speed of
photography. For best results- with- color, the following l/30 second at 16 frames per second. Since the shutter
steps sre suggested: - speed is proportional to the frames per second, the follow-
ing relation between frame speed and shutter speed will
l. Set the scale cover glass so that the etched lines ap- show: pear oyer the speed of the film in use.
FRAME SPEED SHUTTER SPEED
2. Take a close-up reading of the brightest color in 8 frames per second l/ls sec. the scene. Note that Black and White are not to be
considered as colors. 16 frames per second l/3O sec.
24 frames per second L/45 8ec.
3. Move the knurled ring so that the colored dot is 32 frames per second l/60 sec. pointer opposite the indication. Then read off the 48 frames per second l/9O sec. f. stops - shutter speed combinations as in Black 64 frames per second 1/l2O sec. and White.
If an actual close up reading is impossible, take sub- To get the motion picture exposure, apply the exposure
stltuted readings. For example, the palm of your hand index on the calculator in the usual manner. Select the
instead of a person's face. \ best exposure-diaphragm comhination by using the shut. ter speed corresponding to the frame speed of the carnera.
Thus, if your camera has a normal shutter speed of
9. Exposure lo, Motion Picture Cameras l/30 sec. and you want to photograph with a frame speed
The DeJur Autocritic 50-A Cine exposure meter has a of 24, the applicable shutter speed is L/45 s€c. If the
calculator on which the exposure is indicated in "frames shutter speed does not appear on the calculator, use the
per second". The diaphragm opening for a given camera next shorter exposure; in this case l/50 sec.
speed and light intensity is shown directly on the cal- Note the numbers 8, 12, 16, 24, 32 and the word
culator. "frames" on the calculator. These numbers represent
L2 13View original page 8Page 9 · Read text
{rames per second for a nrotion picture camera having a Inatrently marked on the filter-mount is, therefore, likely
.shutter speed of l/30th second. l'lrey determine the cor' to be inaccurate for difTerent filnrs and under varying
rect "f itop instead of the shutter speed. For exampte: conditions.
Opposite l6-frames (nert to l/30th second) is "f" 4 in the \\/hen using filters, consult a reliable table for the ap. illustration, opposite 24 frames (nexL to l/50th second) is propriate filter factor for tlre specific lilm and filter you 'fhen"'f" 3.5, etc. are using. determine the exposure for unfiltered
The correct diaphragm opening will be indicated bv light in the usual rnanner and multiply by the filter factor
the f-r'alue aligned rr ith sclected €r[re5g1etime. to olrtain the exposurefor the filtered light.
It must be remembered that filter factor tables are not
IO. Color and ilIotion Pictttre Cumerns. to be regarded as being conrpletely accurate. They will
E.ractly the same tccltniqtre should be used for motion serve, horvever, as a rough guide upon which to base in-
pictures as for stills. Set the Film Speed. Take a close'tt1' itial experience.
high light reading. Set the colured dot oppositethe pointcr Do not try to secu,re a d.irect reading by holding the indication.
filter ouer the cell ol the nteter! This does not result in
the correct exposure for various technieal reasons which
I I, Correclion Iu, Filters need not be gone into at this point. Adhere to the factor
.\ pltgtsgral,[ic frlter pre\ents a 'l'he['art of t[e original method of compensating for filters in exl)osure.
lii:lrr f rcrttrI)assinginto tlte cantera. intensitl' of liglrt
rrr,licatetll,) tlre erposure nteter will, then be greater
tlrun thc inttnsitl uf the filtered liglrt entering the camera. 12. Use ol Exposure in Printing
Ct,nsequcntlythe correct exposure for filtered light will The DeJur exposure meter can be used as an aid in be greiter tltatr the exposure short'n b1' the calculator for contact or projection printing. First determine by ex. unfiltered liglrt. periment the best printing time for a negative which wiil The ratio of the exposure for filtered light to the ex'
be used as your standard with a particular grade of paper posure for unfiltered light is called the flter tuctor.
The filter factor dependsupon the nature (color) of the and developer. By measuring the light transmitted by
filter, the quality of the light and the sensitivity of the other negatives, you can compute the printing time re-
film. All three conditions must be known to determine quired for these other negatives when using the same
the appropriate filter factor. The factor usually' per' type of paper and developer.
l l 15View original page 9Page 10 · Read text
Care must be exercised in measuring the light transn
mitted by the negative in such a way as to obtain aaerate
light readings representative of the oaerall density of
the negative.
ln contact printing, place the exposure meter in such
position that the light f rom the contact printer passes
through the negative before reaching the meter.
In projection printing, hold the meter either in the
plane of the printing pal)er or at the lens of the enlarger,
so that the enlarger light passes through the negative.
lf the meter is held at the lens, a different standard will
have to be established for various distances from lens
to paper.
Adjust the calculator so that the 800 block on the
"Exposure Index" scale is aligned with the lowest block W;) .-^'/ciuon the "Light" scale of the calculator. For any light value
indicated by the pointer, the corresponding number on
the "Exposure Index" seale will be an indication of theaverage relative density of the negative. We rvill call this --'ys'{
number the density nurnber of, the negative.
Suppose the standard negative has a density number *Bg200 and requires 3 seconds to print on a given paper and
rvith a given developer; and suppose the density number
of another negative is 50; then this second negative will
require Y+ of 3, in other words, 0.75 second to print, using
the same paper and developer. If a third negative has a AUTOCRITIC MODEL 5O.A
density of 400, then similarly, it will require 6 seconds
to prinL
16 t7View original page 10Page 11 · Read text
13. Zero Adiustment c(frrect combinations of exposure time (shutter speed )
To check the meter for its proper zero setting, hold and lens diaphragm opening.
!'our hand over the cell rvindow so as to cut ofr,all light. The I\Iodel 50-A is provided with a honeycomb'l'his tight-
i'tt" pointer should now point to the lorvest mark on the ba[He in f ront of the photo-electric cell. bafile re.
scale, in other words, ir should indicate zero light in' st.ricts the exposure meter's angle of light acceptance
tensity. If it does not register zero, turn the zero set screw to that of the average camera lens.
until ihe pointer does register zero. Check the meter at
regular intertak, 6'Autocritid' I5. Detur Model flO-A-Cine
The "Autocritic Model s0-A-Cirre was designed in re- ftAutocritid' IlIodeI 5O'A sponse to a demand for a direct-reading meter calibrated14. DeJur
ex pressly for use with motion picture canreras. In ap.
The Nlodel 50-A is a direct-reading photoelectric ex' pearanee, size, shape, workmanship and accuracy it dup-
posure meter. The pointer moves llong a series of red di' licates the "Arrtocritic," the only important difierence
i'irionr on the staiionary dial of the calculator. These being in the calculator scales.
divisions can be aligned witlr the exposure index num'
bers on the movable dial. The t\vo etched lines on the A lock-button is provided on this rirodel by means of
st.ale glass are furnished as a convenienee in setting the which the calculator dial may be locked. This feature
meter."The glass should be rotated rvith the fingers until enahles the dial to remain at a fixed film speed so that no
the space bJtween the lines is directly over the speed in changing of position is necessary for each reading.
use. The "A utocritic" 50-A can be used for motion picture
In operation, first consult yogr List of ASA-Exposure work as well as "stills," but the "Autocritic" 50-A Cine
Index Numbers to determine the exposure index of tlre is faster in use due to the scales reading in speeds and
lilm you are using. Then hold the meter in the appropriate lens diaphragm stops common on motion picture camera$
position. The poitttet qill then come to rest at one of the Hence, it is a logical choice for those who confine their
ied divisions or one of the intermediary white divisions work to motion pictures exclusively.
on the stationary dial. Adjust the movable dial so that
the film's exposure index number is aligned wit-l11he di'
vision indicaied by the pointer. The "Time" and "f'scales
on the calculator-will then be in position to indicate the
18 19View original page 11Page 14 · Read text
.'AUTOCRITIC'' MODEL5O-A
EXPOSUREMETER
..AUTOCRITIC" MODEL5O.A
.,CINE" EXPOSUREMETER
..YERSATILE I"
lzr/ax3r/alENLARGER
,.VERSATILE II''
l3vqavqlENLARGER, ,.VERSATI LE PROFESSIONAL''
(axsfENLARGER
"De JUR8.' MOTIONPICTURE
CAMERA
"De JUR8" MOTIONPICTURE
PROJECTOR (
Seetheseproductsat your local pho-
tographicdealeror writefor literature.
24 rQgFrPxpx-e-4Q.rRView original page 14From the M. Butkus archive. Original publisher and archive notices are retained.
Check the model and edition against your equipment.
PDF verified 2026-10-10.