Light meters
BEWI Precision Exposure Meter User manual
User manual for BEWI Precision Exposure Meter. 12 pages in German. Read the original PDF, download or print a copy without registration.
12 pagesGerman0.8 MB PDF
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Document details
- Brand
- Bewi
- Model / document
- BEWI Precision Exposure Meter
- Document type
- User manual
- Language
- German
- Pages
- 12
- File size
- 0.8 MB
- Category
- Light meters
- Document date
- Not specified in catalog
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Page 2 · Read text
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PrecisionExpoiurel*letel
(Reg istered Design)
For the
Reliable Tropics
Strong Lig ht
Irpld ltlfustment. ErtremeluSimpleilanlpulatlon.
P;nted in GermanyView original page 2Page 4 · Read text
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The nrost important factors for the production of
good photos are : correc€ exposure and ths right stop.
The , Bewi " Exposure Meter
measures the necessary exposure and gives you the correct
stop under all conditions of light and with absolute relia=
*) WorkingInstturtions:
rhe scale ring musf ffrst be ad;usted to the ,rSdreiner..
degree sensitiveness of lthe plate or fflm you are _of
using. To do this, hold the instrument as show. b"lo* ,
f G : : .
/
t
See that the spring snaps into the notcb.
') Read lhis carefully : it is imporfan{.View original page 4Page 5 · Read text
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Now pull the lens tube out as far as it will go, remove
your spectacles or eye glasses, apply the eye=piece firmly
to your €y€, point the meter towards a piece of sky and
push the lens tube slowy in again until the numbers
visible in the instrument are deffned as sharply as possible.
This is (he ltermanen( focus or adjus(men(' for
individual eyesigh( and mrrs( be c,arried orr( wi(h
care. When making this adjustment hold the iostrument,
as follows:
'l'{
\ .'l
Ile careful not to expose your eyes fo a strong glare
just before using the meter. Now point the meter at
the object you wish to photograph so that it appears on
the blue screen. (The eye:piece must be held ffrmly
against the eye; if you look into the instrument with
your right €V€, the left hand is held so as to cover or
shade the left €V€, and vice versa). After looking through
'readingthe instrument for a certain length of time (the
*,time') note the highest nurnber yorr can easily read
without straining your eye. After this, remove the meter
from your eye and turn the rib tube with the arrow
mark to the lieht value on the scale rin g corresponding
to the number found by the reading as explained above ;
you can then read off the correct exposure with the stop
corresponding to this exposure in the long aper€ure, as
shown in the accompanying illustrafion.
') Tbe ,eaAing limes apperlaining lo di/fetenf objecls are given on lhc me(er
meier ikelf and also on page 7 under ihe beading ,Final Remarhs',
4View original page 5Page 7 · Read text
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If the Iight is very gla=
ring (midday srJnr snow-
ffelds, expanse of water
and the like), use your
free hand, as shown in
in the accompanying illu= )
"r, stration, to shade your
and thus prevent any \ "ye r insress of false light at
the side of the eye,piece.
In cold weather i€ may happen that the lens becomes
dimmed through the warmth from youreye; if this happens,
lift tbe eye=piece away from the eye for a moment, kee=
ping the object on the screen in view the while; the lens
will then immediately become, clear again. Now hold the
ele=piece again to the eye and after two or three seconds
take the reading
In order to extend the sphere of usefulness of this
meter, a Depth of Focus Table has been provided on
the outer tube for the usual focal lengths used by amateurs.
further a Table for the longest permissible exposure of
moving objects, and also a sumrDary of the working in=
structions ; ffnally the exposures for double extension of
the bellows and for different colour fflters have been added.
SperialRemarks.
i 1.) O.t snow fields with their dazzling lieht and also
on wide expanses of water exposed to the sun the hrr=
man eye after a time tires and temporarily diminishes in {IIpower. In sudr cases it is necessary to extend the rr€?=
ding time' to one or one and a half minutes, so that
a6he eye has time to recover from the glare. After long
and tiring tours on strongly illuminated snow=ffelds or
glaciers, it is recommended to adjust the instrument one
light value higher than was found by the actual reading.
2.) When photographing by artiffcal lieht (to whid:
must also be red<oned moonlight) see to it that the source
of light is not in front of the instrument during rr€:r=
tiView original page 7Page 8 · Read text
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sr.lrement (in whidr case the light itself would be dea=
sured) but rather at the side of or behind you; of cou.rse
yotr mus€ not stand so ,that your body casts a shadow
on tbe object to be photographed. The reading shotrld
be taking after 10 seconds reading time. For expostrres
of this kind use only ortodrromatic plates or fflms.
FinalRemarksahdPointsto Remember.
I) Adjust fo pla{e sensifiueness(Scheiner; Hurfer&
Drifield degrees, G eneral Rating).
2) Focus lens accura/ely on numbers in ins{rumenf .
.7) Never fake {he reading wheo {he eyes are dazzled,
4) Hold fhe eye=piece frmly fo {he eye, so fha{ no
false light can en{er.
5) Indoors, in {he fwiligbf, wben fhe shy is clouded
or when phofographing by arfifcial ltght, {ake
{he reading af{er 1.0 seconds ,,reading {ime" and
in lhe case of arfifcial lighf adjusf {he ins{ru=
ment one ltghf ualue lower fhan {haf found by
fhe reading,
6) In sunshine and in all cdses of sfrongly illu=
minafed objec{s, face {he reading affer 20 seconds
of ,,reading fime"
t 7) Oo datrling snow=frelds or strongly illumina{ed
egpanseso/'wafet, waif one minufe before tahing
fbe reading.
B) Aftt" long and fifing fours on strongly illumi=
na{ed snow or ice frelds, waif L tlz minuf es before
fahing fhe reading and ,zdius{ insfrumen{ one
light value higher {han {he acfual reading.
7View original page 8Page 9 · Read text
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If you follow the above instnrctions, and provided that
the insfentaneous shutter* and the diaphiagm of the
camera function correctly in accordance with the data
given on the camera, then faulty exposures will be practi=
cally impossible.
The data in the diaphragn (stop)column of {he ,BEWI"
lvleter are given according tlro the F .System lfocal length
divided by diame(er of aperture), whidr is now almost
universally used.
Oo the , meter the sensitiveness of the negative
aaterial is expressed in "Sdreiner" degrees; on nearly
all plate and fflm wrappers the sensitiveness will be found
indicated either in Scheiner degress or according to some
other system (see below ; if no sensitiveness is given
on the pa&et, then ask your photo dealer.
In order to be able to use this meter in combination
with cameras in which the stops are designated according
to some o{her system, or with plates or fflms the sensi.
fiviness of whi& is designated otherwise than in Sc}einer
degrees, two tables have been provided at the end of
this booklet giving the comparative values of all systems
of stops and also of thevariotrs sensitometerdegree, oi""",.".
A Few Examples.
1)It is intended to photo=
graph an inferior Sensiti=
veness of the plate or fflms
17 degrees Scheiner: we
therefore adjust €he ecale
ring to 16 - 180. After fo=
cussing the lens to suit
your individual eyesight,
as explained above, and
after waiting 10 seconds
g time ", the nrrmber"readin
5 is noted_as easily decipherable. Accordingly, adjust arrow
mark to 5 on the scafe ring. Then read ofi: expo"o.e fo.
stop 4.5 : 3 seconds; for stop 6.3 - 6 seconds, a.rd so on
i,7l]lr""o^mended
lo baue lbe speed of fbe shufier &e&ed from rime rolime by un eTperl.
8View original page 9Page 10 · Read text
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9.) In the case of an exposure to be made by arti.
ficial lieht (sensitive ness of plate 20u S&reiner), after
10 seconds of reading time only the number I is
decipherable; since with artiffcial Iight we must adjust
one light value lower than the number read, we here
adjust the arrow to 0 on the scale ring. Then read off:
exposure for stop 4 5 : 12 minutes i for stop 6.3 - 25 rl,i-
nutes and so forth.
Readingthe Erposurefol (lnematf,0il,
In the case of cinema work the shutter speed of your
apparatus (appertaining to the number of exposures per
second) must ffrst of all be de{ermined You then mea=
sure the exposure exactly as in fhe case of ordinary
photographic work and then you need only adjust the
stop of your camera in accordance with the value found
on the meter opposite to the exposure (shutter speed)
to whic} the camera has been adjusted. If this exposure
is not contained under the lieht value in question, (.hen
the illumination of the object is not strong enough for
exposures fo be made.
Examples.
Tlte necessary slop is
Witb a seclo, and a number of lbe sbdller
foqnd on lbe melet
aperlure of eNposures of speed is opposile lo
tlzz to llsq bei l/az sec.
sec. u 16 per sec. 160-180
2 0 , 7llo to 1l+s between 1/42
sec. and l/sn sec.
o
G e t a L e a t h e r C a s e { r o m y o u r d e a l e r f o r y o u r
Exposure Meter. The meter can then be carried on the
belt and the instrumenf is protected against, sho&s and.
weather inflrrences.View original page 10From the M. Butkus archive. Original publisher and archive notices are retained.
Check the model and edition against your equipment.
PDF verified 2026-10-10.