Pentax digital spotmeter User manual

DIGITAL
SPOTMETER
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ISPECIFICATIONS
L
MeasuringRange:
Scales:
Measuring
Angle:
MeasuringDistances:
MeasuringMethod:
Exposure
Read-Out:
Photosensitive
Cell:
Power
Source:
Battery
Check:
(100
ASA)EV 1
- 20 (EV
20displayed
as
"0").
ASA,6 - 6400;Shutter
Speed,ll4OOOsec.
- 4 min.;
Aperture,f
l1 - 128;
EVNumber,l
-19-213;
lRE,
1- 10.
1"_
From
about1.5mto infinity
- f
ixed
focal
length.
(Focusing
downto about
1m
possible
by screwingtheeyepiece
out
as
far
as
itwillgo).
Spot
rrreasuring
of reflectedlight.
(Meter
switcheson when
button pressed).
LED
digitaldisplayof EV Numbers
(100
ASA),
and
up
to two
dots
(each
of
whichequals
+ 1/3
EV).
Silicon
Photo
Diode
One6V silver oxide
battery
(No.
544or equivalent)
or No. 537
alkalinebattery.
Failure
of LED
digitaldisplayto illurninate
indicates
battery
needs
replacing.
-\
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Viewfinder:
F
ilterSize:
Dimensions:
Weight:
Additional:
Pentaprism
type
with unreversed,laterallycorrect
image.Objectiveand
eyepiecelensesSuper-Multi-Coatedand
pentaprism
speciallysilvered
for
brilliant
viewfinderimage.
Even
illuminationachieved
with f inely
grooved
fresnellens.1ospotindicatedincenter
of viewfinder,andlarge
LED Panel
appearsat
thebottom.
Viewfindercoveragesimilar
inshapeto that of a 35mm
SLR,
and
with adiagonal
f
ieldof view of 26"
,horizontal
f
ieldof 22"
,and
verticalf
ield
of14",
adjustable
eyepiece
of -2 Lo
+1 diopter.
40.5mm.
44mm(D)x 144mm(H) x B3mm(W).
25Bg
(withbattery).
Equipped
with Tripod
Socket,
supplied
with case,WristStrap,
battery,and
LensCap.
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NOMENCLATUR
E
Objective
Lens'-- *-^j
Metering
Button "*'-'
ASA lndex
ASA Scale
ASA/Shutter
Speed
Dial
- Shutter
SpeedScale
---
Aperture
Scale
Aperture/EVNo.Dial
*-'-
EV No.
Scale
lR
E
Scale
lR
EStandard Index
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Battery
Chamber
Cover
Tripod Socket
Wrist
Strap
Eyelet
EyepieceAdjustment
Lock
Ring
Eyepiece
Lens
Eyepiece
(R
ubber)
Frame
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ISPECIAL
FEATURES
1. Small
enough
to be
pocketable.
2. Lightenough to carry
anywhere.
3. Strongly
resistant
to shock
(no
moving
parts
in
exposuremeasurement
system).
4. LEDdigitaldisplayvisibleunder
any lighting
co
nd
ition.
5. Can
follow the fastest
actionandwork inthe
dimmestsurroundings
becauseof the
instantaneousresoonse
of the
Silicon
Photo
Diode.
6. Human
engineeredfor theperfect
grip
and
optimumhandling
ease.
7. Objective
and
eyepiece
lenses
Super-Multi-
Coatedand
pentaprism
specially
silvered
for
brilliant
viewing.
8. StabilizerCircuiteliminates
LED
f
licker
for
comfortableviewino.
9. Digitaldisplay exceptionallylargefor viewing
ease.
10. Digital display
(EV
No.,
100ASA)
given
in 1/3
EV stepsto match
the
ASA, ShutterSpeed,
Aperture,and
EV No.
Scales
for precise
and
easy
to make settings.
11
. Theminute1o
angleof view of theD
igital
Spotmeter
isequivalent
to a
40 power
ultra-
telephotolens,
making
it possible
to take
accurate
exoosu
re measurernentsof
adistantsubject.
12. Onlywith a spotmeterisit possible to separately
measure
allof thetonesof a
given
subject,from
the brightesthighlight
to thedarkestshadow.
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BATTER
IES
Illust.
5, Rotatecounterclockwise
with acoin
and
remove
the BatteryChamber
Cover
O
found
on thebase
plate
of the
Grip.
Illust.
6, Insert,
plus-side-down,
a 6V silver oxide
battery
(No.
544or equivalent) or a No. 537
alkalinebatteryintothe Battery
Chamber,and
replacecover
(minus
side
of battery
faces
cover).
A Batterv
CheckCircuitisconnected
to the LED
digitaldisplaysothat
illumination
of thedisplay
indicates
battery
condition
is
good.
lf the
digital
display
appears
f
aintor
f
ails
to illuminate,
the
batteryshouldimmediately
be
replaced.
Battery
lifeisconsiderable,
and
even
with constant
use
the battery
should
last
a year;
nevertheless,it is
alwaysadvisableto carry
a sparebatteryto be
prepared
for emergencies.
Electricity
will
not
be
consumed
aslongas
theMetering Button isnot pressed, evenwhen
lightenterstheObjectiveLens. However,
even
whennot used,maximum battery
lif
e is two years.
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OUTLINEOFOPERATING
PROCEDURE
Illust.
T
& B,
While
looking
through
the
viewfinder
(
@, illust.
B)
at
adistant
object,rotate
counter-
clockwise
the
Eyepiece
Adjustment
Lock
Ring
(@,
illust.
B
& 9)
untilthe
smallcirclein
thecenter
of
the
viewf
inder
(i
o
spot)
appearssharp.Next,
squeeze
the
Metering
Button
(@, illust.
1
1
)
to
determinewhether
the
digital
display
(illust.
7)
alsoappears
sharp.lf it
doesnot
appearsharp,
7
readjust
theEyepiece
Adjustment
Lock R
ingto
a
midway
point
so
that
boththe
digital
display
and
1o
spotappearreasonably
sharp.
Illust.
9, After adjusting
the
eyepiecef
or maximum
sharpness,hold
therubber
Eyepiece
Frame
securely
(@, illust.
9) so thatit
does
not
move,
and
lock
it into
place
by rotating
theEyepice
Adjustment
LockRing
(@, illust.
g) clockwise
8
7
\
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until it stops.When someone
elseis
to use
the
spotmeter, rotate the Eyepiece Adjustment Lock
R
ing counterc
lockw iseto loosen eyep
iece,
readjust
eyepiece,
and lock it into place
once again.
Illust.
10, Align the ASA No. of the f
ilm being
usedwith the
green
ASA lndex (@, illust.1O)
by
rotating
the ASA/Shutter Speed Dial (@) which
isclose
to the front of the lens @ . The f
igures
of the ASA Scale
also
appear in green.
I 10
Illust. 11
, While holding the spotmeter up to your
eye,
alignthe 1" spot in the center
of the viewf inder
with the part of the subject you wish to measure.
Sq
ueeze
the Metering Button and an LE
D d
igital
display
will appear.
In illust J, Ihedigitaldisplay
indicates
13-213
EV; it a single
dot appeared, it
would indicate13-1
13
EV, and if no dot appeared,
it wou ld indicate
exactlv 13 EV.
11
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12
-1.2 Illust.12-1
& 12-2,
Alignthe EV No. indicatedby
thedigital
displaywith the lRE Standard
lndex
( @ ) by rotating
the
AperturelEV
No.
Dia|
(@ ).
Boththe IREStandardIndexand
thenumeralsof theEV No. Scaleare
colored
Orange.After
aligning
the
EV No.with the
Standard
Index,
merely
selectany aperture-shutter
speed
combination
indicatedon the respective
scales.ln illust. 12-2,
for example,it canbeseen
that
whenthe
ASA setting is100
and
EV No. i 3
is
aligned
with the
Standard
Index,
any
of the
following
combinations
resultincorrectexposure:
t
l1
.4,1
I4OOO
sec.,
f
12,
1/2000
sec.
t122,1115
sec.
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CINEINDEX
Theoperation
of the spotmeter for moviecameras
differssomewhatfrom thatof still
photography.
Theshutterspeedof movie
camerasis
determined
by camera
type,theshutter
openingangle,
and
whetherthe
cameraisbeingusedfor highor
lowspeed
photography.
Thestandard
shutterspeedof the
ordinary35 and
16mmmovie
camera
isapproximately1/50
of
asecond
(24frames
per
second).This speed is
marked
in red
on the ShutterSoeedScalebetween
the 1/30and 1
/60 sec.divisions.Theref
ore,when
usingthe meter
with thesecameras,
theaperture
opening
is
found on theAperture
Scalebelow
this
mark.
With
Bmm movie cameras,
the
Super-B
andSingle-B
typestake1Bframes
per
second,
andthe Double-B
type takes
'l
6 f rames
persecond.In both cases,
the
proper
apertureopening
will befound on the
Aperture
Scalebelow
the 1/30sec.mark.
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IRE
{INSTITUTE
OF
RADIOENGINEERS)
The Pentax Digital Spotmeter is
provided with
an IRE Scale
which is
very useful f
or television
filming
and movie mak
ing,
as
well as
genera
I
photography. 12O
Pentax Spotmeter II's equipped
with IRE Scales
inrBreused
to provide exposure
settings
for the making
of the officialfilm of
the 1
964 Tokyo Olympics.Sincethat time, this
scale
has
come to be usedwhenever comoarable
precision
in exposure
settingiscalled
for.
SCALE
IRE units provide a means
for the percentage-
wise comparison of energy. The maximum energy
value istaken to be 1OO%
and energy levels
taking
this maximum asa standard are expressedas
percentages
of maximum level This method is
usedin radio communications to compare signal
voltages,
but is alsoapplicableto the comparison
of light energy obtained in exposure measurements
The light levelof the brightesthighlight in the
subject istaken as 1
OO%and the energy of other
parts
of the subject isexpressedin I
RE units as
a fraction of that level.
lndex 10 (1OO%
lRE
) indicatesthe levelof the
brightest
highlight
in the picture,
the upper bright-
nesslimit, and iscalledthe "white level
"
f
ndex 1 (O% |R
E
) shows the maximu
m dark
ness
of shadow detail reproducible
on the f ilm. This is
caIled the " Black level.
"
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The intermediate
numbers
9 -2 (90 - 20% IRE)
indicatecomparative brightnessbased on the 1OO%
"White level."
These indices
represent
divisions
of
the linear
gray sca
le.
The largeorange triangular index between 3 and
4 is
the Standard Index, in useon most light meters,
which shows the average of optimum f ilm exposure
levels
(light levelobtained using
standard reflecting
surface,
ret
lectivity
ratio of 1B%).
The f igure
"1:32" at the extreme left
of the scale
indicates
the contrast ratio between lR
E scale
1
and 10 The IRE scales
from 1 to 10 cover5 light
levelnumbers Sincean increaseof one EV number
represents
a
doubling of light level,the contrast
ratio is 1
:32 Qs = 32\
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i
VAR]OUSII4ETHODS
OFEXPOSURE
READ]NGS l
Methodsof expo6ure
readingincludethe half- The spotmeter
will prove
itselfespeciallyvaluable
tone reading
method, the avoraging method, the for measuringexposureof persons
standing under
highlightreading
method,
and
the shadow stagespotlightsand in similarly
difficult situations.
readingmethod. Since
the half
-tone
method measuresin half
-tone
only, it is
verysimple,but the clueto successlies
Inthe way in which the half-tone
ref
lectivityratio
HALF TONE READING METH0D is
measured.Measurethegray 18
percent
standard i
Centerthe 1" spoton a half-tone areaof primary reflection
carddirectly or elsesomething
with !
interestand takethe reading
for that point. lf, for areflectivity ratio very closeto it to get the
example,the sub.iect
is
a peison, aim the 1" spot bestresults. t
at his or herJace lf the subjectisan object or I
a landscape, select
anareaof averagetonal
quality AVERAGING METH0D
andplace the 1' spot in that area. Measurethe highlight
(brightest)
and shadow
After readingthe light level,alignthis number . (darkest)
areas
andtake the average
of the
with the IRE Standard Index.Selectan appropriate readingsobtained.
The best
resultswill beobtained
setof valuesfor shutterspeedand apertureopening if the differencebetween
the highlightsand
from the two scalesin the centerof the exposure shadows
isno greater than the reproducible
calculator. contrast
ratioof the
f
ilnl.
For black and
white
1A
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reversalf
ilm this
differenceis
approximately 7 EV
numbers;for color reversal
f
ilm and black
and
white prints it is
approx imately 5 EV nu
mbers.
With color prints,
the difference
is less
than 5 EV
numbers. lf the contrast between highlights
and
shadows exceeds these ranges,
measure the light
of at least
three locations in the picture areaand
dividethe sum of readings
by the number of
locations
measured
to obtain an average value.
Setthis
average
value
by the Standard Index. In
thiscasethe high light
areasbeyond the f ilm's
reproducibility
range
will beoverexposed,
or
the shadow areas will be underexposed By this
method, however, one will have
obtained correct
exposurefor the greatest
area
of the picture
asa
whole
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FOR
THE SPECIALIST
This isa method f
or which the Pentax Digital
Spotmeter is
uniquely adapted. In th
iscase,
the
light level
of the subject
highlights
are made
the base
va
lue
for exposure sett
rng Th is
method
was
developed
for television
f
ilming,
but is
just as
usef
uI
for still
and moving picture photography As
previously
mentioned,
the max
imum reproducible
contrast ratio differs according to f
ilm type, krut
generally
speaking
this ratio isthe same
for color
film as
f
or television
broadcasting,
about 1
"32'
The ratio
f
or black
and white f
ilm isapproximately
1.128 To use
this
method,
the light
level
of the
hrghlights
is
first
determined,
and this
EV value
taken as
the upper exposure
limit By doing this
the optimum exposure
will be based
on the light
areas
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The
light
level
read
at
the
highlights
is
set
on the
exposure
calculator
by index
10of the IRE
Scale.
With
color
film,only
those
shadows
with a light
level
reading
fallingto the
rightof index1
of the
IRE
scale
(black
level)
will be
reproduced.
Areas
with
a light
value
falling
below
index
1
will
appear
as
unrelieved
shadow.
Therefore,
when
the light
levelof the highlights
hasbeenset
on index
10,
if important
shadow
detail
has
insufficient
lightto bring
it above
index
1,it
willhave
to be
given
additional
illumination
untilits
lightlevel
readingdoes
exceed
this
mark.
EXPOSURE
FOR
SPECIAL
EFFECTS
Highlight metering isalso
a convenient means
of
achieving an underexposed, low-key effect which
isdesirable
when creating
a nocturnal atmosphere
in a da
yti me shot.
To achieve this effect, read the light level of the
highlights,
and set
this number on the exposure
calcu
lator by one of the lR
E indexes
chosen in
accordance with the degreeof density desired in
the resu
lti
ng photograph.
Forexample,
if
the light
levelof the
highlights
is
EV 16,
and
this
valueisset
on the
exposure
calculator
by the
standard
index,the highlights
will be
reproduced
in
a
gray
tone
as
if they
were
a
standard
18%
reflective
surface.
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SF{l\ilff\,V
ffiFAUlNfi
IVIFT[-{0D
The reverse
of the highlight reading method, this
method gives
an optimum exposure based
on the
shadow areas.
Shadow read
ing is
em
ployed f
or
bringing out detail of persons
pirotographed with
backlighting,
and for fully reproducing
shadow
detail in pictures taken at night.
When ordinary light meters are used to set
exposure for evening
or nighttime scenes
which
are
not brightly illuminated by neon or other
lighting,
the resulting
photograph has
the same
appearance
as
a daytime scene.
By using the
spotmeter and the shadow reading
method,
exposures can be set to give evening scenes
an
"Evening-look" and nighttime scenes
a
"N ighttime-look."
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Read
the light values
of the shadow areas it is
desired
to reproduce, and setthis light level
on
the exposurecalculator
by IRE index i .
In this case,
areas
of light value falling between
indexes1
and 10 on the IRE Scale
will be
reproducibleon color f
ilm. Areasof light
value
fa
llingabove index 1
0 w ill be washed out.
Consequently,if important high lightdetail has
a light level
falling
above
index 10 when shadow
light level
has
been setaccording to index 1, it
wi
ll be nec.essary
to reduce illumination of
the highlight area,
or to reducethe reflectivity
of the highlight,until its light levelfalls
on or below index 10.
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