Gossen MetraWatt Luna-Pro sbc Instruction Manual
-
GOSSEN
®
Luna-Pro
sbc
Instruction
Manua
l
7909-1057YO
This Luna-Pro
sbc
Instruction Manual
is
more
than just
an
instruction book - it
is
actually a short
course
in
the creative use of
an
exposure meter.
Section
I offers "Basic Operating Instructions".
To
use your Luna-Pro sbc properly you need only read
and
follow the simple instructions
in
this section.
Section
II,
however, moves a step forward - to
"Getting the Most Out Of
Your
Luna-Pro sbc." Here
you can
really find out how to put the unique
versatility of your Luna-Pro sbc to work for you.
Section
III
gives you "Helpful Hints" for special
shootings - action, snow and sand, sunsets, night,
and more - the type of information you need for
that extra creativity.
And Section
IV provides you with full details
on
the
"Accessories" for your Luna-Pro sbc - to turn it into
a true exposure system.
We
sincerely hope that this manual will be of help
to you and will answer most of your exposure
measurement questions.
If
it does not, feel free to
contact your
specialist dealer.
In
addition, our Con-
sumer Service Department
is
available for help
with special requests.
2
Cong
ratu
lations!
You
now
own
one of the most advanced ex-
posure
meter,
the heart
of
the Luna-Pro
sbc
System.
The new Luna-Pro sbc System
is
the most flexible,
versatile
and adaptable photographic light measur-
i
ng
system ever devised, while at the same time
being very
simple to use.
In
order to get maximum
benefit from the
quality design and operating features of this precision instrument, please take a few
minutes to
read
this instruction manual.
Your
new Luna-Pro sbc utilizes the latest advances
in
silicon cell sensors and also high performance
electronic circuitry including integrated circuits
to
provide fast, accurate, repeatable readings under
the most
difficult professional conditions.
The Luna-Pro sbc represents a most significant
development
by
Gossen GmbH, Erlangen, West
Germany, Europe's
largest manufacturer of preci-
sion electrical instruments since
1919,
and one
of
the outstanding pioneers in exposure meter design
since
1932
.
Table of Contents
Section
I.
Basic Operating Instructions . 5
I.
a. Zeroing the Meter . . . . . . . . 5
I.
b.
Inserting & Changing the Battery 5
I.c. Setting the Film Speed . 6
I.
d. Exposure Factor Scale . 6
I.
e.
Making a Measurement . 7
I.
f. Reading the Scales . . . 7
Section II.
Getting the Most Out Of
Your
Luna-Pro sbc .
10
II.
a.
Continuous or Stored Readings . .
10
II.
b. The Null Method of Measurement .
11
II.
c. Exposure Correction Dial .
12
Il.d. Footcandle Readings
with the
Luna-Pro sbc . . .
13
II.
e. Carrying Case . . . . . . .
14
11.1.
Methods of Measurement . .
14
Il.g. Incident Measurement . .
17
II.
h. Reflected Measurement . .
18
II.
i.
Scene Brightness Range .
19
lI.j. Color Crossover. .21
Il.k. Zone Systems . . . . . . .
21
11.1.
Film Reciprocity Failure
....
.
Il.m. Intermediate f/stops
..
.
...
.
Il.n. Intermediate Footcandle Values
and Exposure Time . . . . . . .
Section III. Helpful Hints . . . . . . .
Ill.a. Choosing Between Action Stopping
Ability and Depth-of-Field .
IIl.b . Snow&Sand .
IIl.c. Sunsets
..
.
Ill.d. Night Lighting . . .
II
I.e. Backlighting
..
. .
111.1
. Copying
.....
.
Ill.g. Excessive Skylight
Ill.h. Bellows (Extension) Factor
Section
IV.
Accessories . . . .
Section
V.
Using Luna-Pro Attachments
Section VI. Appendix . . . .
Service
.........
. . .
Specifications . . . . . . . . .
Additional Reference Material
24
24
25
26
26
27
27
28
28
29
29
29
32
37
38
39
40
.
41
3
Operating Parts & Scales
1.
Spherical Diffuser
2.
Green Zero Check Point
3.
Meter Needle
4.
Power Switch
5.
Cine Scale
6.
Electronic Flash
Reference Mark
7.
Battery
Test
Button
12
8.
ASA Index Triangle
21
9.
Film Speed Scale
10.
Exposure Correction Dial
13
11.
Computer Dial
14
12.
Battery Test Zone
15
22
13.
Exposure Correction Signal
14.
Exposure Time Scale
15 .
Aperture Scale
16
16.
Film Speed Setting Disk
17
17.
Exposure Value Scale
18
18.
Exposure Factor Scale
19
Index Mark 23
19.
Zone System Scale
20.
Measuring Cell Window
(under diffuser)
21
.
Zero Adjusting Screw
22.
Table of Footcandle and '.
Lux Values
23 .
Battery Compartment Lid
Basic Operating Instructions
The following instructions are a quick operating
guide to the Luna-Pro sbc. For best results,
also
read
the additional sections describing
in
more
detail the different functions of the Luna-Pro sbc.
La. Zeroing the Meter
With the battery removed, check to see that the
meter
needle
(3)
rests
on
the green zero check point
(2). If
not, turn the zero adjusting screw
(21)
until
the needle rests
on
the zero mark.
ca
.
Lux
mit
Diffuso~
bei
18
DIN
'e'
Ie
appr
o
I.
b. Inserting & Changing the Battery
Your
Luna-Pro sbc
is
supplied with a 9-volt battery
which fits into the battery compartment
at
the bot-
tom of the meter.
Slide the battery compartment lid
(23) off and attach the battery to the battery clip
inside. Note that the battery can
only be connected
one
way.
Insert the battery into the battery com-
partment and
slide the lid back on. Check the
battery
by
pushing and releasing the power switch
(4)
and then pushing
in
and holding the battery test
switch (7). The meter
needle should be well within
the battery test zone
(12)
.
5
I.c. Setting the Film Speed
Determine the ASA speed from the data supplied
by
the film manufacturer. Rotate the clear film speed
setting disc
(16)
by
the raised bars until the ASA
speed number
is
opposite the white ASA index
triangle
(8).
A detailed ASA film speed table
is
on
page
36.
I.
d.
Exposure Factor Scale
Check to make sure that the exposure factor scale
(10)
index mark
(18)
is
at
1.
A more detailled expla-
nation of this useful scale
is
on
page
9.
6
I.
e.
Making a Measurement
Select the method of measurement desired, either
reflected or incident. (For details
on
inciden1
vs
.
reflected measurements,
see
section
II.
f. For
reflected readings slide the spherical diffuser
(1)
to
either side of the meter. For incident readings,
slide the sperical diffuser
in
front of the measuring
cell
window
(20)
unit
it
"snaps" into the detent.
Aim
the meter at the subject for a reflected light
reading or
at
the camera for a incident reading.
Depress
and
release the power switch (4). Rotate
the computer dial
(11)
until the meter needle
is
over
the "0" null line.
Read
the desired combination of
f/stops and shutter speeds
on
the computer scales.
NOTE: When
you
release the power switch, the
value measured
at
that moment will
be
automati-
cally read,
and
electronically stored
by
the Luna-
Pro
sbc.
To
conserve battery life, the meter
switches itself off automatically after
30 seconds,
and
your measurement set
on
the
computer dial
remains for convenient
and
repeated reference.
For
continuous measurements,
see
page
10.
I.
f.
Reading the Scales
The Luna-Pro sbc has six scales used
to
give
you
information
on
ASA index, aperture, shutter speed,
cine speed, exposure
value
(EV)
, and exposure
factor (EF).
In
addition, accessory clip-on scales
are available for direct reading of other light
measuring
values such
as
footcandles.
7
The time, or shutter speed scale
is
calibrated from
1/4000 of a second to 8 hours
and
indicates values
as
follows:
Hours are indicated 8h, 4h, etc.
Minutes are indicated
30m,
15m
, etc.
Seconds are indicated 30, 15, etc.
Fractional seconds are indicated '2, '4, etc.
Note that each section
is
alternately colored from
the
adjacent sections for ease of reading. The
red
A/
indicates the proper reading point when using the
electronic flash attachment. See page
34.
The ASA scale
is
calibrated
in
standard ASA values
from 0.8 to
100
,000 (100K). Intermediate values
are shown
by
short lines. A complete table listing
these intermediate values
is
on
page 38.
CAUTION: Because of the extreme measuring
range of the
Luna-Pro sbc, it
is
possible - under
exceptional conditions of very high
or
low light
levels
combined with a very high or low ASA index
- that the computer
displays both ends
of
the expo-
sure time
scale (8h and 1/4000 sec.) When this
occurs, the CORRECT reading
will
be
the
UPPER
part
of
the scales!
8
EXAMPLES:
ASA 25,000
at HIGHEST LIGHT LEVEL:
Scales.show
(above) 1/4000 sec. at
11128
but also (below) 8 hours at f/5.6 etc.
Obviously, HIGH ASA and HIGH light level add
up
to SHORT exposure - 1/4000 sec.
at
f/128.
ASA 0.8 at LOWEST LIGHT LEVEL:
Scales
show (above) 8 hours
at
f/2.8 etc.
but
also (below) 1/4000 sec. at f/64
etc.
Obviously
LOW
ASA and
LOW
light level
add
up
to
LONG
exposure - 8
hours
at f/2.8.
The
apertu~e
or flstop scale
is
calibrated from fl
128
to f/
O.7.
Numerical values are shown
on
the scale
at
full flstop increments. Intermediate values are indicated
by
short lines
at
1/3 stop increments. A table
of intermediate values
and
the mathematical
for-
mula for calculating f/stops are given
in
section
III.
The zone system scale indicates values from I
to
IX. These are the values commonly used
in
various
zone systems and represent a continuous grey
scale
of
print values ranging from black to white.
Further
explanation
on
use
of
zone system scales
are given
in
Section
II.
k.
.
The cine scale allows direct reading of apertures
for various cine speeds
(f
rames per second).
These speeds correspond
to
actual exposure times
on
the exposure time scale only for cameras hav-
ing
standard shutter angles. For
XL
cameras or
those with
adjustable shutter angles, consult the
camera's instruction book for the
equivalent shutter
speeds
and
read your exposure opposite that
speed
on
the time scale. Also note that some reflex
viewing movie cameras use beam splitters
to
pro-
vide a
light path
to
the viewing screen. These beam
splitters reduce
the
light intensity
to
the film plane,
so
that a correction factor must
be
applied
to
the
indicated
f/stop. Once determined, the correction
can
be
programmed into the exposure correction
dial.
An
EV
(exposure value) scale
(17)
is
provided for
cameras with shutters
calibrated
in
EV.
The Luna-
Pro
sbc
EV
scale
is
calibrated from
-8
to
+24.
Numerical values
are
shown for full
EV
values with
intermediate
values indicated
by
short lines at 1/3
EV
intervals. Exposure values
are
used elsewhere
on
several scales which will
be
explained later.
It
is
important
to
remember that a change of 1
EV
is
equivalent
to
a change of 1 f/stop.
An
EF
(exposure factor) scale
is
included for mak-
ing
exposure corrections when using filters, bel-
_ lows,
extension tubes, etc.
It
is
calibrated for expo-
sure factors
up
to
64.
Detailed information
on
this
scale
is
in
section
II.
c.
9
10
Getting the Most
Out of
Your
Luna-Pro sbc
The preceding condensed instructions gave you
information
on
the basic operating procedures for
your
Luna-Pro sbc. However, this meter
is
extremely versatile, and the following information will
acquaint you with the many creative possibilities
available
to you when using your Luna-Pro sbc.
Il.a. Continuous or Stored Readings
The Luna-Pro sbc
is
capable of either continuously
reading or storing light values. For simplicity of operation, the
read
and hold method
is
used. For eva-
luation of different lighting levels such
as
when
using zone systems, the continuous method
is
used. Both methods are activated
by
the same
power switch.
To
operate the meter
in
the
read
and
hold mode,
the power switch
ON
/OFF button index mark
(a)
must
be
aligned with the square switch position
indicator
(b).
Simply depress and release the
power switch. The meter
will automatically read
and
electronically hold the value of the light level
present
at
the moment when the button was relea-
sad.
Because advanced electronic circuitry
and
a
silicon blue cell are used
in
the Luna-Pro sbc, the
measurement
is
instantaneous with
no
memory or
lag.
This reading will
be
stored and available for a
period of
30
seconds after the button
is
released.
After the one minute period, the meter automatically
turns
itself off, prolonging battery life. Additional
readings can be taken
at
any time
by
repeating the
above sequence.
To
operate the meter
in
the continuous mode, sim-
ply depress and hold the
ON
/OFF button
in.
The
meter
will now respond
to
all changes
in
light
values.
For long term measurements, the ON/OFF
switch has a lock position which
is
indicated
by
the
round switch position indicator
(c).
To
activate and
lock the meter on:
1)
Depress and hold the power switch
in.
2)
Rotate the switch button clockwise until the
index mark
is
aligned opposite the round switch
position indicator.
The meter
will now remain
on
for constant readings
until the switch button
is
rotated counterclockwise
opposite the square position indicator where the
read
and
hold mode will
go
into operation for one
minute, after which the meter
will again turn itself
off.
NOTE:
Be
sure to return the switch button
to
the
read
and
hold position (square mark) after using.
Failure
to
do
so
will result
in
short battery life.
II.
b.
The Null Method of Measurement
Laboratory instruments have
long used the null
method of measurement for obtaining precise readings. This method has been incorporated into
your
Luna-Pro sbc for maximum accuracy and
ease of reading.
The basic operating difference between the Luna-
Pro
sbc and a conventional meter
is
that, instead of
using various points
along a complete scale length,
only
one position (the null point)
is
used for all rea-
dings and at
all light levels. This results
in
greater
accuracy and ease of operation. There
is
no need
to change
scale ranges or
to
read different scales.
When the needle
is
set
at
the null point, the compu-
ter
instantly shows a complete read-out of the mea-
surement.
To
expand the capabilities of the Luna-Pro sbc
further, its meter face
is
also calibrated
in
1/3
EV
increments from the null position to ± 3
EV
for use
in
scene brightness measurements
and
zone
system
applications. Additional information
on
this
extremely useful feature will
be
found
in
section
II.
i.
If
the meter needle
is
placed
in
the "over" or
"under" range, the readings
on
the calculator dial
will result
in
over or underexposure
by
the value
indicated, compared to a standard exposure.
Each
numerically indicated major division
on
the
meter face
equals one
EV
(a change
of
one EV
equals a change
by
one flstop or one shutter speed
setting); the
small intermediate dots are equal to
1/3
EV.
11
II.
c.
Exposure Correction Dial
Occasionally,
the indicated exposure readings
obtained with any
light meter must
be
modified for
best
results. This
is
especially true when using fil-
ters or when taking close-up pictures where the
longer lens to film distance results
in
reduced light
at
the film plane.
To
correct for these effects, com-
monly called filter
factor and bellows (extension)
factor,
additional exposure must be given to the
film.
In
addition, you may, for various creative
reasons, wish to depart from the standard
exposure values. For these situations, the Luna-Pro
sbc, with its exposure correction dial,
is
ideal.
Normally
when making exposure corrections, the
correction factor must be
calculated and applied
each time a reading
is
taken. However, with the
Luna-Pro sbc, the exposure change can be programmed into the exposure correction dial. Any
readings then
will automatically be corrected
as
taken.
The exposure correction
dial
is
calibrated
to
work
both
in
EV (exposure value)
and
EF (exposure fac-
tor).
Two
index marks are provided at the center or
normal positions for each correction method.
In
addition, the
red
exposure correction signal gives a
12
visual indication any time the exposure correction
dial
is
in
use.
:fo
use the exposure correction feature, determine
the correction factor desired,
in
either
EV
or
EF,
and rotate the exposure correction dial while holding the computer
ring
stationary until the white
index mark
is
opposite the correction value. Any
readings now taken
will reflect this correction.
For
example, assume that a filter with a filter factor
of 4 x
is
being used which represents a change of
2 stops. By moving the index mark of the
EF
ring to
a position opposite the number 4, the meter
read-
ings will automatically
be
compensated for the 2
stop difference.
Rotating the exposure correction dial corrects the
indicated exposure by changing the shutter speed
(and
flash symbol), cine speed, and EV scales.
Therefore, this feature can
be
used for still photo-
graphy using available light and artificial ligth
including flash,
motion picture photography, and
wi
th
cameras calibrated only
in
EV.
After completing "corrected" measurements, be
sure
to
return the correction dial
to
its "0" posi-
tion (red signal will
be
covered by\ black tab).
ILd. Footcandle Readings
With The Luna-Pro
sbc
The Luna-Pro sbc
is
a precision instrument
designed to give
highly accurate photometric read-
ings specified
in
readily usable photographic terms.
However,
footcandle readings can also be obtained
with the
Luna-Pro sbc, either by converting the
photographic reading or
by
use of
an
accessory
snap-on
footcandle scale.
A conversion table of EV to footcandle readings is
included on the underside of the meter.
To
deter-
mine the equivalent footcandle reading, set the
ASA film speed scale
to
50, slide the spherical dif-
fuser over the cell window for incident readings,
point the meter toward the
light source and take
an
EV reading (null the meter). Turn the meter over
and read the
footcandle value opposite the EV
reading just obtained.
Similarly, lux values can also
be
determined. Note that for each change of one
EV,
the footcandle level changes by a factor of
2.
This
is
because the EV scale is equivalent to a full
stop scale
in
that each change of one EV or one
f/stop
results
in
either twice or half the amount of
light. A formula suitable for calculating intermediate
values of footcandles is given
in
section
III
along
with pre-calculated values at 1/3 EV increments.
For direct reading of
footcandles,
an
accessory
snap-on
footcandle scale is supplied with the
Studio Attachment. When attached, this scale
allows
quick , direct read-out of
t~e
equivalent foot-
candle
readings without having
to
change ASA
values
or using a conversion table. Detailed
instructions for its use are included with the scale.
The most precise footcandle readings are obtained
by
means of a flat diffuser such as the one supplied
with the Studio Attachment. When using the spherical
diffuser of the Luna-Pro sbc, all the light falling
on the diffuser from
an
angle of approximately 180
0
is integrated for a final reading. Since most photo-
13
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