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This Luna-Pro sbc Instruction Manual is more thanjust an instruction book - it is actually a shortcourse in the creative use of an exposure meter.

Section loffers "Basic Operating Instructions", Touse your Luna-Pro sbc properly you need only readand follow the simple instructions in this section.

Section ll, however, moves a step forward - to"Getting the Most Out Of Your Luna-Pro sbc. Hereyou can really find out how to put the uniqueversatility of your Luna-Pro sbc to work for You. .Section lll gives you "Helpful Hints" for specialshootings * action, snow and sand, sunsets,night, and more - the type of information you needfor that extra creativity.

And Section lV provides you with f ull details on the"Accessories" for your Luna-Pro sbc - to turn itinto a true exposure system.

We sincerely hope that this manual will be of helpto you and will answer most of your exposuremeasurement questions. lf it does not, feel free tocontact your BMG specialist dealer. In addition, ourConsumer Service Department is available for helpwith special requests.

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Congratulations !

You now own the most advanced exposure meter,the heart of the Luna-Pro sbc System.

The new Luna-Pro sbc System is the most f lexible,versatile and adaptable photographic lightmeasuring system ever devised, while at the sametime being very simple to use. In order to getmaximum benefit from the quality design andoperating features of this precision instrument,please take a few minutes to read this instructionmanual.

Your new Luna-Pro sbc utilizes the latest advancesin silicon cell sensors and also high performanceelectronic circuitry including integrated circuits toprovide fast, accurate, repeatable readings underthe most difficult professional conditions.

The Luna-Pro sbc represents a most significantdevelopment by Gossen GmbH, Erlangen, WestGermany, Europe's largest manufacturer ofprecision electrical instruments since 1919, andone of the outstanding pioneers in exposure meterdesign since 1932.

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Table of Contents

Section l. Basic Operating Instructions ' ' " "l.a. Zeroing the Meterl.b. Inserting & Changing the Batteryl.c. Setting the Film SPeed

l.d. Exposure Factor ScaleLe. Making a Measurement .

l.f . Reading the Scales

Section ll.Getting the Most Out Of Your Luna-Pro '

ll. a. Continuous or Stored Readingsll. b. The Null Method of Measurementll. c. ExPosure Gorrection Dial .

ll. d. Footcandle Readingswith the Luna-Pro sbc

ll. e. Carrying Case .

tl. f . Methods of Measurementll.g. Incident Measurement ..ll. h. Ref lected Measurement . .

ll. i. Scene Brightness Rangell. j. Golor Crossover

fl.h. ZoneSYstems.. ""'21f l.l. Film Reciprocity Failure " " 22

ll. m. Intermediate f /stoPs ' ' 23

ll. n. Intermediate Footcandle ValuesandExPosureTime "'23

Section lll. HelPful Hints ' ' 24

lll. a. Choosing Between Action StoppingAbility and DePth-of-Field ' ' 24

.f lf . b. Snow & Sand " ' 25

lll.c. Sunsets """'25lll. d. Night Lighting " 26

lll. e. Backlighting " ' 26

lll. f. Copying .. " " ' 27

lll. g. ExcessiveSkYlight " ' 27

ttt. n. gettows(Extension)Factor .... " 27

SectionlV.Accessories. "' 30

SectionV.Appendix.'.r.!.. "" 35

Service " ' 37

Specifications. """ 38

Additional ReferenceMaterial ."' 39

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Operating Parts & Scales1. Spherical Diffuser2. Green Zero Check Point3. Meter Needle4. Power Switch5. Cine Scale6. Electronic Flash Reference

Mark7. Battery Test Button8. ASA Index Triangle9. Film Speed Scale

10. Exposure Gorrection Dial11. Computer Dial12. Battery Test Zone13. Exposure Gorrection Signal14. Exposure Time Scale15. Aperture Scale16. Film Speed Setting Disk17. Exposure Value Scale18. Exposure Factor Scale

Index Mark19. Measuring Gell Window

(under diffuser)Zero Adjusting'ScrewTable of Footcandle andLux ValuesBattery Compartment Lid

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Basic Operating InstructionsThe following instructions are a quick operatingguide to the Luna-Pro sbc. For best results, alsoread the additional sections describing in moredetail the different functions of the Luna-Pro sbc.

l. a. Zeroing the MeterWith the battery removed, check to see that themeter needle (3) rests on the green zerc check point(2).lt not, turn the zero adjusting screw (20) untilthe needle rests on the zeto mark.

l. b. Inserting & Ghanging the BatteryYour Luna-Pro sbc is supplied with a 9-volt batterywhich fits into the battery compartment at thebottom of the meter. Slide the battery compartment

lad (221off and attach the battery to the battery clipinside. Note that the battery can only be connectedone way. Insert the battery into the battery com-partment and slide the lid back on. Check thebattery by pushing and releasing the power switch(4) and then pushing in and holding the battery testswitch (7). The meter needle should be well withinthe battery test zone (12).

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l. c. Setting the Film SPeedDetermine the ASA speed f rom the data supplied bythe film manufacturer. Rotate the clear film speedsetting disc (16) by the raised bars until the ASAspeed number is opposite the whlte ASA indextiiangle (8). A detailed ASA f ilm speed table in onpage 35.

l. d. Exposure Factor ScaleGheck to make sure that the exposure factor scale(10) index mark (18) is at 1. A more detailed expla-nation of this useful scale is on page 9.

l. e. Making a MeasurementSelect the method of measurement desired, eitherreflected or incident. (For details on incident vs.reflected measurements, see section ll. f. For re-flected readings slide the spherical diffuser (1) to

either side of the meter. For incident readirgs,slide the sperical diffuser in front of the measuringcell window (19) until it "snaps" into the detent.-

Aim the meter at the subject for a reflected lightreading or at the camera tor an incident reading.Depress and release the power switch (4). Rotatethe computer dial (11) until the meter needle is overthe "0" null line. Read the desired combination off/stops and shutter speeds on the computerscales.

NOTE: When you release the power switch, thevalue measured at that moment will be automati-cally read, and electronically stored by theLuna-Pro sbc. To conserve battery life, the meterswitches itself off automatically after one minute,and your measurement set on the computer dialremains forconvenient and repeated reference. Forcontinuous measurements, see page 10.

l. f. Reading the Scales

The Luna-Pro sbc has six scales used to give youinformation on ASA index, aperture, shutterspeed, cine speed, exposure value (EV), andexposure factor (EF). In addition, accessory clip-onscales are available for direct reading of other lightmeasuring values such as footcandles.

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The time, or shutter speed, scale is calibratedfrom 1/4000 of a second to 8 hours and indicatesvalues 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 fromthe adjacent sections for ease of reading. The red 0lindicates the proper reading point when using theelectronic flash attachment. See page 32.

The ASA scale is calibrated in standard ASAvalues from 0.8 to 100,000 (100K). Intermediatevalues are shown by short lines. A complete tablelisting these intermediate values is on page 35.

CAUTION: Because of the extreme measuringrange of the Luna-Pro sbc, it is possible - underexceptional conditions of very high or low lightlevels combined with a very high or low ASA index

- that the computer displays both ends of theexposure time scale (8h and 1/4000 sec). Whenthis occurs, the CORRECT reading will be theUPPER part of the scales!8

EXAM PLES:

ASA 25,000 at HIGHEST LIGHT LEVEL:Scales show (above) 1/ 4000 sec at t / 128but also (below) 8 hours at f/5.6 etc.

Obviously, HIGH ASA and HIGH light level add upto SHORT exposure - 1l4OO0 sec. at l/128.

ASA 0.8 At LOWEST LIGHT LEVEL:Scales show (above) 8 hours at t/2.8 etc.but also (below; 1/4000 sec. at f /64 etc.

Obviously LOW ASA and LOW light level add upto,LONG exposre - 8 hours al t/2.8.

The aperture or f/stop scale is calibrated fromt / 128 to f /0.7 . Numerical values are shown on thescale at full f/stop increments. Intermediatevalues are indicated by short lines at 1/3 stopincrements. A table of intermediate values and themathematical formula for calculating f/stops aregiven in section lll.

The cine scale allows direct reading of aperturesfor various cine speeds (frames per second).These speeds correspond to actual exposuretimes on the exposure time scale only for camerashaving standard shutter angles. For XL cameras orthose with adjustable shutter angles, consult thecamera's instruction book for the equivalentshutter speeds and read your exposure oppositethat speed on the time scale. Also note that somereflex viewing movie cameras use beam splittersto provide a light path to the viewing screen. Thesebeam splitters reduce the light intensity to the f ilmplane, so that a correction factor must be appliedto the indicated f/stop. Once determined, thecorrection can be programmed into the exposurecorrection dial.An EV (exposure value) scale (17) is provided forcameras with shutters calibrated in EV. TheLuna-Pro sbc EV scale is calibrated from -8 to+24. Numerical values are shown for full EVvalues with intermediate values indicated by shortlines at 1/3 EV intervals. Exposure values are usedelsewhere on several scales which will beexplained later. lt is important to remember that achange of 1 EV is equivalent to a change of 1

f /stop

An EF (exposure factor) scale is included formaking exposure corrections when using filters,bellows, extension tubes, etc. lt is calibrated forexposure factors up to 64.. Detailed information onthis scale is in section ll. c.

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Getting the MostOut of Your Luna-Pro

The preceeding condensed instructions gave youinformation on the basic operating procedures foryour Luna-Pro sbc. However, this meter isextremely versatile, and the following informationwill acquaint you with the many creativepossibilities available to you when using yourLuna-Pro sbc.

ll. a. Gontinuous or Stored ReadingsThe Luna-Pro sbc is capable of either continuouslyreading or storing light values. For simplicity ofoperation, the read and hold method is used. Forevaluation of different lighting levels such as whenusing zone systems, the continuous method isused. Both methods are activated by the samepower 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 positionindicator (b). Simply depress and release the10

power switch. The meter will automatically readand electronically hold the value of the light levelpresent at the moment when the button wasreleased. Because advanced electronic circuitryand a silicon blue cell are used in the Luna-Prosbc, the measurement is instantaneous with nomemory or lag. This reading will be stored andavailable for a. period of one minute after thebutton is released. After the one minute period,the meter automatically turns itself off , prolongingbattery life. Additional readings can.be taken at anytime by repeating the above sequence.

To operate the meter in the continuous mode,simply depress and hold the ON/OFF button in.The meter will now respond to all changes in lightvaf ues.'For long term measurements, the ON /OFFswitch has a lock position which is indicated by

the round switch position indicator (c). To activateand lock the meter on:1) Depress and hold the power switch in.

2) Rotate the switch button clockwise until theindex mark is aligned opposite the roundswitch position indicator.

The meter will now remain on for constantreadings until the switch button is rotatedcounterclockwise opposite the square positionindicator where the read and hold mode will gointo operation for one minute, after which themeter will again turn itself off .

NOTE: Be sure to return the switch button to theread and hold position (square mark) after using.Failure to do so will result in short battery life.

ll. b. The Null Method of MeasurementLaboratory instruments have long used the nullmethod of measurement for obtaining precisereadings. This method has been incorporated intoyour Luna-Pro sbc for maximum accuracy andease of reading.

The basic operating dif ference between theLuna-Pro sbc and a conventional meter is that,instead of using various points along a completescale length, only one position (the null point) isused for all readings and at all light levels. Thisresults in greater accuracy and ease of operation.There is no need to change scale ranges or to readdifferent scales. When the needle is set at the nullpoint, the computer instantly shows a completeread-out of the measurement.To expand the capabilities of the Luna-Pro sbcfurther, its meter face is also calibrated in 1/3 EVincrements f rom the null position to t 3 EV for usein scene brightness measurements and zonesystem applications. Additional information onthis extremely useful feature will be found insection ll. i.lf the meter needle is placed in the "over" or "under"range, the readings on the calculator dial willresult in over or underexposure by the valueindicated, gompared to a standard exposure.

Each numerically indicated major division on themeter face equals one EV (a change of one EVequals a change by one f/stop or one shutterspeed setting); the small intermediate dots areequal to 1/3 EV.

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ll. c. Exposure Correction DialOccasionally, the indicated exposure readingsobtained with any light meter must be modif ied forbest results. This is especially true when usingfilters or when taking close-up pictures where thelonger lens to f ilm distance results in reduced lightat the film plane. To correct for these effects,com mon ly called f ilter f actor and bellows(extension) factor, additional exposure must begiven to the f ilm. In addition, you lTlay, for variouscreative reasons, wish to depart from the standardexposure values. For these situations, theLuna-Pro sbc, with its exposure correction dial, isideal.Normally when making exposure corrections, thecorrection factor must be calculated and appliedeach time a reading is taken. However, with theLuna-Pro sbc, the exposure change can beprogrammed into the exposure correction dial.Any readings then will automatically be correctedas taken.The exposure correction dial is calibrated to workboth in EV (exposure value) and EF (exposurefactor). Two index marks are provided at the centeror norrnal positions for each correction method.in addition, the red exposure correction signal12

gives a visudl ind\ication any time the exposurecorrection dial is in use.

To use the exposure correction feature, deter-mine the correctign factor desired, ih eitherEV or EF, and rotatb the exposure correction dialwhile holding the computer ring stationary untilthe white index mark is opposite the correctionvalue. Any readings now taken will reflect thiscorrection.

For example, assume that a f ilter with a f ilter factorof 4x is being used which represents a chan ge of 2stops. By moving the index mark of the EF ring toa position opposite the number 4, the meterreadings will automatically be compensated forthe 2 stop difference.

Rotating the exposure correction dial corrects theindicated exposure by changing the shutter speed(and flash symbol), cine speed, and EV scales.Therefore, this feature can be used for stillphotography using available light and artificiallight including f lash, motion picture photography,and with cameras calibrated only in EV.

After completing "corrected" measurements, besure to return the correction dial to its "0" posi-tion (red signal will be covered by black tab).

ll. d. Footcandle ReadingsWith The Luna-Pro sbc

The Luna-Pro sbc is a precision instrumentdesigned to give highly accurate photometricreadings specified in readily usable photographicterms. However, footcandle readings can also beobtained with the Luna-Pro sbc, either byconverting the photographic reading or by use ofan accessory snap-on footcandle scale.

A conversion table of EV to footcandle readings isincluded on the underside of the meter. Todetermine the equivalent footcandle reading, setthe ASA f ilm speed scale to 50, slide the sphericaldiff user over the cell window for incident readings,

point the meter toward the light source and takean EV reading (nullthe meter). Turn the meter overand read the footcandle value opposite the EVreading just obtained. Similarly, lux values can alsobe determined. Note that for each change of oneEV, the footcandle level changes by a factor of 2.This is because the EV scale is equivalent to a fullstop scale in that each change of one EV or onef /stop results in either twice or half the amount oflight. A formula suitable for calculating inter-mediate values of footcandles is given in section lllalong with pre-calculated values at 1/3 EVincrements.

For direct reading of footcandles, an accessorysnap-on footcandle scale is supplied with theStudio Attachment. When attached, this scaleallows quick, direct read-out of the equivalentfootcandle readings withou.t having to change ASAvalues or using a conversion table. Detailedinstructions for its use are included with the scale.

The most precise footcandle readings are obtainedby means of a flat diffuser such as the onesupplied with the Studio Attachment. When usingthe spherical diffuser of the Luna-Pro sbc, all thelight falling on the diffuser from an angle ofapproximately 180" is integrated for a final

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reading. Since most photographic subjects arethree dimensional, this results in more accuratephotographic exposures, but can give improperfootcandle readings.When using the spherical diffuser, footcandlereadings are most accurate when reading directlight beams such as from spots, arc lights, etc.

li. e. Garrying CaseYour Luna-Pro sbc is supplied with anexceptionally strong and functional carrying case.It is constructed of the f inest heavy-duty materialsfor long life and extra protection for the meter.Extra thick material and heavy stitching make thiscase suitable for the abuse encountered inprofessional usage. The complete top section ofthe case is removable for ease of handling whentaking frequent exposure readings.14

To insert the meter, open the case by unstrappingthe fastener at the rear of the case and swingingthe top section forward. Insert the meter strap

through the openings at the rear of the case. Placethe meter into the bottom section of the case andsecure with the retaining strap. To remove the topsection of the case completely, unsnap the fastenerat the bottom of the case.

ll. f. Methods of MeasurementThere are two basic methods of obtainingmeasurements with the Luna-Pro sbc, incidentand reflected light readings. Both methods arepopular and when used properly, both are validand will give good results. However, to evaluate

properly the ways in which these two methodsfunction, it is necessary to discuss brief ly how themeter operates and how film responds to light. ltis beyond the scope of this manual to get into adetailed discussion of sensitometry, the study oftone reproduction. There are many excellent booksavailable on the subject, some of which are listedin the appendix. This manual will just relate insimple terms, how the Luna-Pro sbc works andunder which conditions you may wish to use eitherincident or ref lected light readings.Alt films have characteristic responses to lightwhich, although they may vary f rom f ilm to f ilmand with changes in storage and processing, arerelatively predictable. This consistency ofresponse is what allows the use of light metersand other photographic instruments to predict thefinal outcome of an exposure.

F.ilm responds to only a limited range ofillumination levels before its ability to recoid thatlight illumination level properly is lost. Anyinstrument designed to measure or expose filmmust take that into consideration. The response ofthe film to light is generally graphically illustratedby what is called a "characteristic curve" or H & Dcurve, named for Hurter and Driffield whooriginated its use. Although it is not necessary to

use such a curve to determine exposures, usingone as an illustration will help in evaluating properlight measuring techniques. A repres-entativesample H & D curve for a film is illustrated below.

1.50 1.80 2.1Q 2.4O

This curve shows, "ronn'uJff things, the change

of density of the film vs. the log of the exposure.With negative film, as the exposure increases, thenegattve density increases. lt is broken down intothree distinct regions, the toe, straight lineportion, and shoulder. In order to record detailproperly on film, the light values (log exposure)should fall within the range where they intersectthe straight line portion of the curve. lf theexposure falls into the area of the toe or shoulder,the film will lose shadow or highlight detailrespectively. This is because, once those areas are

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reached, little or no change in film density occurswith a change in exposure, and it is the change ofdensity that produces differentiation and detail.Therefore, your light meter must give you anexposure value that will adjust the measured lightso that when it reaches the film, it will fall withinthe straight line portion of the film's recordingab i lity.

The H & D curve shown above indicates relative logexposure. However, because different films havedifferent light sensitivity ranges which wouldaffect the density vs. log exposure in actual use,the meter must be programmed for thesedifferences. The ASA f ilm speed setting control onthe calculator dial of the meter accomplishes thisprogramming.

In order for this ASA value to be meaningful, allmeters and other light measuring devices thatrelate to photographic applications must take intoaccount not only the film speed, but also theref lectivity of the object being photographed. Thisis because the film does not know what thereflectivity of a particular object is. lt onlyresponds to light levels. Therefore, all otherconditions being equal, a light subject with a lowlevel of illumination may record on film the same16

\as a dark object with a high level of illumination.To standardize these varying conditions and toallow you to work with different meters and films,a ref lectance of 18% value and the understandingthat it represents a "typical average" is the basisfor readings taken with both ref lected and incidentmethods of measurement, although under thesame lighting conditions, different readings forthe same scene can be obtained when using bothmethods, depending on subject reflectivity. Thismay seem strange at first, but it is true, andsometimes causes confusion. To eliminate thisconfusion (something no meter or other devicecan do), you must consider your subject matterand how you want it to appear on the film. Forsimplicity, the discussion of this evaluationmethod will be broken down into a discussion ofincident and reflected light measurements.

ll. g. Incident MeasurementWhen reading incident light, the spherical diffuseris placed in front of the measuring cell windowand pointed toward the camera, i.e. opposite thesubject being photographed, so that the diffuserwill receive the same light intensity and

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distribution as that lalling on the subject. Thereading at this point indicates the strength of thelight, but does not indicate the light valuereflected from the subject into the camera lens andonto the f ilm. lt does indicate the light value thatwould be reflected into the lens from an 18ohaverage reflective subject. Therefore, whenworking with subjects that are primarily very lightor very dark, the incident exposure readingindicated should be adjusted to compensate forthe difference in reflectivity from the 18o/ostandard. When the subject is very light, decreasethe exposure by 1/2 to 1 f /stop. When the subjectis very dark, increase the exposure by 1/2 to 1

stop. The amount of change to the exposure willdepend on your judgement as to tllg degree ofvariation in subject reflectivityfrom an average scene.

\Situations may arise where you have extremes oflight and dark subjects, all of which are importantin the same scene. Under these conditions, themeter should be used in the ref lected light methodas described under scene brightness range andzone systems.Incident light readings are most valuable whendetermining exposures where the subject isinaccessible and receives the same illumination asthe meter. They also allow you to determine theindividual strengths of multiple light sourcesstriking one subject by reading each sourceindependently. In most cases with average subjectmatter, the incident method is a fast, simple andaccurate way to determine exposure.

ll. h. Reflected MeasurementWhen reading reflected light, the meter is pointedtoward the subject and light reflected from thesubject passes through a collecting lens onto themeasuring cell. This is the same type of path thelight takes when exposing film in your camera.The meter cannot "read" any single element in itsfield, such as a face or highlight; it integrates allthe light ref lected throughout the measuring f ield,and indicates an exposure which will record thetotaf picture on the basis of an overall 18o/o value.

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In most cases, you can simply use this reading toget a perfectly exposed picture. However, there area few situations where the readings should bemodified.

The Luna-Pro sbc has a measuring angle of 30'when taking a reflected reading. The light from allobjects within that 30' measuring range will beaveraged to give you the f inal reading. lf you haveone or more objects that are significantly lighter ordarker than the rest of the scene, the objects willbias the reading away from the average. In casessuch as this, the meter should be moved in closerto the main subjects of interest or one of theaccessory spot attachments used to eliminate theeffect of the light or dark areas. As an alternative,an incident reading can be taken.

When measuring a subject that departs signifi-cantly from an 18o/o reflective surface, you maywish to modify your readings. This is because thereading indicated will make the subject appear onthe film as if it were 18o/o reflective.

tn certain cases, you may not want the subjectbeing measured to fall into that category. Forexample, if the indicated reading is set in yourcamera when measuring a brilliant white bridalgown, the resulting image of the gown on the filmwill appear with the same density as if it were 18o/ogray instead of white. Here again, you may wish touse an incident reading or compensate theref lected reading by increasing exposure. The sameis true for very dark objects, i.e., a black tuxedo,except the exposure would be decreased.

Reflected readings are particularly useful whentrying to evaluate the relative range of reflectedlight from various subjects that may have differentref lectivity and may be receiving different amountsof light. Because the reflected reading measuresthe light reaching the lens, differences inref lectivity and level of illumination are accountedfor. Therefore, you can determine the extremes anddistribution of light from the scene just the way

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your f ilm will record it. This technique is covered insections Scene Brightness Range and ZoneSystems.

ll. i. Scene Brightness RangeIn order to assure proper exposures for highlightand shadow detail in scenes with a wide range oflight intensity and subject ref lectivity, the extent ofthe lighting range must be determined. TheLuna-Pro sbc is ideally suited for this type ofmeasurement because of its null meter design.

To utilize this function, you must first determine,by testing the limits of exposure change forhighlight and. shadow areas from average that areacceptabJe to you with your f ilm. Once this is done,the cal'ibrated reference scale on the meter willautomatically indicate if you are within acceptablelimits of the film.For example, if your testing with a particular type offilm shows that you could accept an exposurechange f rom average of UNDER (under exposure) 2to OVER (over exposure) 21/z EY, your total rangewould be 41/z EV. Using reflected measurement,you could then read the light from the most impor-tant area of the scene and then null for that reading.Then, without further adjustment of the calculatordial, you could take light readings from highlightand shadow areas and read the EV variance of theseareas. lf , in this case, the readings fall within theUNDER 2 to OVER 21/z EV range, your exposureswill be good. However, if for example, yourreadings resulted in UNDER 3 and OVER 1, you

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would lose shadow detail, even though the totalrange is still only 4 EV. A simple solution wouldthen be to reread the shadow intensity and rotatethe computer dial until the meter needle is opposite2 on the UNDER side which is within the f ilm limits.

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Then recheck the highlights which should now readOVER 2. You would then use the new exposuresetting indicated on the computer dial. Thescene brightness range has not changed, but themeter has adjusted to yourt exposure so that you areworking within the range of the film. To see thisgraphically in terms of f ilm response see the H & Dcurves to the right.

It is important to note that this exposureadjustment method works best when usingnegative films because different density levels canbe adjusted for in printing. With transparencyf ilms, this type of exposure adjustment should beused very carefully because you are viewing theoriginal without the benefit of printing correction.20

0.0 0.30 0.60 0.90 1.20 1.50 1.80 2.10

RELATTVE LOG E

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situations may arise where the meter shows arange of-.light intensity that is beyond the totalIange of f ilm acceptance. In these cases, the use off ill light to ligh-ten shadows or a "gobor' (a device toP!opl,. o.r modify tight such as a dirk card; to softenhighlights may be indicated. When t'he fropercorrective action is taken, the scene brightness

ll. j. Golor CrossoverThe preceeding discussion concentrated on the ef-fects that lighting can have on f ilm, either black andwhite or color. However, with color, three separateemulsions are on the f ilm each of whose individualresponse may be different. In normal exposuresituations all three layers will track reasonablywell, resulting in accurate rendition of color as weilas density. However, at the extremes of exposurelevels, deviations in the characteristic response ofindividual color layers of the film can re'sult in acondition called color crossover. This conditionresults in a color shift in an area of under or overexposure that cannot be corrected withoutaffecting the colors of the properly exposed areasof the scene. lt is therefore very important to avoidthis condition which shows itself as color shifts inthe shadows and hightights.

f l. k. Zone SystemsThere are times when the lighting ranEe cannot bebrought within the acceptabre ilmitior the firmbecause of an inability to f ill or use "gobos" such asryhen photographing landscapes. When thesesituations arise, the exposure levels can be

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range can again bechecked to be surethe lim its of thef ilm are not ex-ceeded . M od if y-ing the lightingcan also be usedinstead of shiftingthe exposure asmentioned aboveif so desired, as inthe case of trans-parency f ilm wherethe main subjectis close to 18% re-flectance such aswith some skintones.

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adjusted so that the most important parts of thescene receive proper exposure. This can be donewith either black and white or color f ilm. However,some detail, either in the highlight or shadowareas, will be lost.When using black and white film, sflothertechnique is available to extend the capabilities ofthe film to record extreme lighting ranges. lt iscalled the zone system. Instead of relying onstandard measurement and exposure techniques,the zone system combines special measurementtechniques, modified exposures, and altered filmprocessing to expand the range of light values thatthe film can accept. ln doing so, detail can berecorded which would otherwise be lost.

A complete discussion of this technique is tarbeyond this manual. References are given in theappendix which should help you become familiarwith this very useful photographic tool.The Luna-Pro sbc is well suited for use with mostzone systems because of its null meter principle ofoperation. Most systems are based on a centralzone, representing a certain lighting level, calledZone 5. From this level, the range of light fromhighlight to shadow is measured and referred tothis central zone. The level of variance from the22

central zone determines the amount of exposurecorrection and processing modif ication, if any, thatis needed. With most meters, the zone equivalentsmust be marked on the face or transferred toanother sheet to correlate with changes in lightlevel. However, with the Luna-Pro sbc, thecomputer dial can be used to adjust the meterneedle to null at any light level. Any subject can benulled for and light variations from that level readdirectly off the meter face in EV. This means thatyou can always set null for Zone 5. Or, you maywish to bias the reading in one direction.

Simply turning the computer dial of the Luna-Prosbc allows you to put the meter needle anywherefrom -3to +3 EV from a normal value. With a littlepractice, you will be amazed at the ease with whichspecialized information chn be gotten.

ll. l. Film Reciprocity FailureAll photographic exposure meters rely on aprinciple of film exposure called recipro-city, to function properly. Basically, the filmintegrates or adds up light ouring exposure toproduce the latent imaoe. Within certain limits,the same image density is acheived for shortexposures of high intensity as with long exposuresof low intensity, as long as the product of intensity

times time is constant. When the exposure timesget very long or very short, however, this reciprocityeffect is lost, and an accurate prediction ofexposure, and color balance with color films,cannot be determined solely by the meter reading.It is therefore important to check the instructionssupplied with the film in use to determine when -reciprocity failure can be expected, how severe itwill be, and how to correct for it. Here again theLuna-Pro sbc greatly assists in exposuredeterm ination because the corrective f ilterssuggested by film manufacturers to adjust colorshifts from reciprocity failure have an effect onexposure. These f ilter factors can be programmedinto the Luna-Pro sbc, and the new, correctedf/stop read directly.

ll. m. Intermediate f/stopsThe Luna-Pro sbc is calibrated in 1/3 f /stopincrements with numerical indications at f uilstops. A table is included below with the actualnumerical values of the 1/3 stop increlnents listedfor levels from t/0.7 lo f /128.Values not listed canbe calculated from the formula that follows.New f /stop = (old f /stop) ( \- (f /stop change);For exampte, if you ,wish to stop down 1/4 stopfrom f/4, take the \2-which equals 1.414 and

Next multiply 4 times 1.09

(0 Go)=4*Your new f/stop is approximately 4.4.

ll. n. lltermediale Footcandle Values andExposure Times

Galculation of intermediate values of footcandlesand exposure times is basically the same ascalculation of intermediate values of f /stopsexcept that the value \l- is reptaced by 2 in theformula.For example, you have a footcandle level 1/2 stopabove 1000 as represented on the chart on the backof the Luna-Pro sbc.

the power .25 wh ich is the deci'malof 1/4 stop.

.zSs (lW})f- t,oj,7(ry)raise it toequivalent

New footc'andle level ==

(old feveD Q $/stoP change);

(1000) (2 (.5)1

(1000( (1.414)1414

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Helpful Hintslll. a. Chqgsing pe_twegn {clion Stopping

Ability ahd Depth-of-FieldAfter taking a light reading with your Luna-Pro sbc,you will have a choice of readings to use which maylook like this:

toward or away from you can be stopped with alower shutter speed than those moving across yourfield. To create a more realistic feeling of motionwith objects moving across your f ield, use a slowershutter speed and pan across the field. Whenpanning, the relative speed between the subjectand the camera is decreased while the relativespeed between the background and camera isincreased. This results in the characteristic actionshot with the main subject sharp and thebackground blurred.

For shutter speeds of 1/60 second and longer, theuse of a good tripod or other camera support issuggested to avoid camera shake and blurredpictures.

When subject speed is not a major factor in yourpictures, you may wish to choose a longerexposure time and stop down for maximumdepth-of-f ield. This extra depth may be especiallyimportant when using long lenses because of theirrelatively shallow depth-of-field. However, withlong lenses, camera shake is accentuated so becareful to use a sturdy support.

Conversely, even when subject speed is not a majorfactor, you may still wish to choose a short shutterspeed and a larger lens opening to intentionally

Time:t/Time: 1/60U8

1/30 1/15 1/811 16 22

1/1000 1/500 1/250 1/1252 2.8 4 5.6

All of them will give good exposures, but, in termsof photographic results, they are all slightlydif f erent.

When shooting action, you generally need a fastershutter speed to get a sharp photograph. Speedsfrom 1/125 to 1/1000 are generally used, with thechoice depending upon the relative speed anddirection of travel of the object. Objects moving24

limit depth-of-field for selective focus. This isespecially useful for eliminating the distraction ofcluttered backgrounds. Portraits lend themselvesideally to this technique.

lll. b.Snow & SandWhen photographing with highly reflectivesurfaces such as snow and sand, extreme careshould,be used when using reflected readings. Inrnost cases, an incident reading will producesuperior results for normal subject in the scene,although the snow or sand may be overexposed. lfreflected readings are desired, the main subjectshould be metered up close or a spot attachmentused to minimize the effect of the reflected light,unless the snow or sand is itself the most importantpart of the scene. This is an ideal time to use scenebrightness range measurements.

lll. c. SunsetsSunsets can present a problem in lightmeasurement because of brightness range. Some-times, the sun itself is the most important part ofthe scene, and at other times, light ref lecting fromclouds or distant mountains may be moreim portant.

You should f irst determine what part of the scene ismost important. Using an incident reading underthese conditions will generally give you poorexposures with washed-out colors. Ref lectedreadings are more accurate, but some compensa-tion is still necessary for the sun or sky. When thesun is present and most important, read the sun

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directly and use that exposure. lf the sky andclouds are most important, read these areas, beingcareful not to read direct sunlight. In all cases, ifpractical, bracket exposures on both sides of thoseindicated. You may get some very striking resultsthat are not apparent to the unaided eye.

lll. d. Night LightingMeasurement of illumination levels at nightpresents several problems to good exposures.

Generally, in outdoor scenes, the lighting is not asuniform as with daylight. Bright artif icial lights cancreate multiple highlights and shadows, with atremendously large brightness range. in addition,26

direct use of the meter readings will result in apicture that appears more like a daylight photo thanone taken at night.

Generally, night exposures get into the area of f ilmreciprocity failure. lt is therefore important to knowthe characteristics of your film before shootingunder these conditions.

After taking film reciprocity effects into account,decrease your indicated exposures by 1/2to 1 stopto preserve the night appearance in your scenes.

lll. e,

BacklightingWhen the main subjectshould be exercised

of interest is backlit, carewhen taking reflected

readings. Light from behind the subject enteringdirectly into the measuring cell of the meter willproduce reading errors. To avoid this, take yourreadings up close to the subject or use one of thespot attachments for more accuracy. An incidentreading can also be used, with the meter pointedtoward the camera. For the most accurateexposures, measurements should be,. made asdescribed in the section, Scene Brightness Range.

lll. f. CopyingCopying places stringent demands on lighting tomake sure that the detail and tonal range of theoriginal is recorded on the copy. Lights are ususallyplaced to the sides of the copyboard to eliminateglare from the surface of the copy. Many peopleprefer to overlight the corners of the copy tocompensate for lens falloff . The exact amount ofoverlighting varies with the individualsituation, but15-200 is com mon.

For copy work, the Luna-Pro sbc can be used withthe copy attachment for determining exposure andchecking evenness of illuminatio1.

lll. g.

Excessive Skylight .,,'When taking reflected readings of scenes wherethere are large areas of skylight, care should beexercised that the main subject be given thegreatest attention either by tilting the meter downtaking up-close measurement or by using one ofthe spot attachments. As an alternative, an incidentreading may be used.

lll. h. Bellows [Extension] FactorWhen photographs are taken where the foctrs is at apoint other than infinity, an exposure correctionmust be made. At most working distances, thiscorrection factor is so small that it can be ignored.

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However, when working at very close distances, itbecomes significant and can result in seriousexposure errors if not corrected for. This exposurevariance is commonly called extension factor orbellows factor.There are several ways to correct for this effect.Two of the most commonly used take into accountthe lens focal length and the lens to film planedistance (bellows extension).The first method gives you an extension factorwhich can be programmed into the exposure factorring of the Luna-Pro sbc for direct readout ofcorrected exposure values. The second methodgives a corrected aperture only.

l, Extension Factor =(Lens to film plane distance)2

(Lens focal lengtn;2

For example, assume a 210mm lens (approximately8") is being used with a lens to film plane distanceof 14".

Extension Factor = Fq)2(8F

= 19964

= 3.06 or approximately 3

In this case, set the white index mark of theexposure factor ring opposite the number 3. Notethat the exposure factor portion of the ring(numbers in black) should be used, not the EVposition. All readings will now be corrected for thisextension factor.

ll. Effective Aperture =(Lens to film plane distance) (lndicated f/stop)

(Lens focal length)

For example, assume the same conditions as inExample I with an indicated f /stop of t/11

Ef fective Aperture = !-9_(11)8

= 19.3 or approximately 20

In this case, if the lens were set to f /8, the exposurelevel would be the same as if the lens were set tot/20, although, depth-of-field would remain thesame as for f/8. Using this method, each time adifferent f/stop is chosen, the same amount ofcorrection must be recalculated into the exposure.The f irst method in conjunction with the exposurefactor ring of the Luna-Pro sbc is much quicker andmore f lexible because once the exposure factor isprogrammed, all subsequent readings arecorrected for with additional calculations and interms of all values, not just f /stops.

Another way to determine extension factor is tomeasure the magnif ication of the object size at thefilm plane. This is especially useful when workingwi,th large format cameras where measurement ofthe image on the ground glass is relatively easy.

To calculate the extension factor, measure both the,actual object size and the size of the image on theground glass. These two measurements are used inthe formula below.

EF -/ lmage Size . . \2\o-5jffi-'l

For example, assume an object size of 2 inches andimage size of 4 inches.

= (2+1)2= Pl2=9

Setting 9 in the EF correction ring of the Luna-Prosbc will give correct exposures for this condition.Extension and f ilter factors can be eliminated f romexposure reading by using the accessory fiberoptics probe and reading on the cameragroundglass. Any changes due to these factors willautomatically be sensed and compensated for bythe meter.

= 154I

EF =(+ *') '

iitltI

!T29

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All of these excellent features are only thebeginning of the Luna-Pro sbc story. The widerange of instantly interchangeable accessories setthe Luna-Pro sbc distinctly above any other lightmeasuring instrument. And, to make them evenmore practical, several of them automaticallyreprogram the meter response for direct reading.With these accessories, you don't have to matchspecial marks or lines to get the right reading. Justattaching the accessory and proceeding with thereading in a normal manner is all that's necessary!

Luna-Sphere Studio AccessoryWhen working in the studio or with multiplesources of light, many professionals prefer tomeasure incident light for exposure determination.This can be done with the basic Luna-Pro sbc, butfor greater convenience, the Luna-sphere combinesits large integrating sphere wlth a 360' swivel head30

plus capability for a flat plane diffuser into oneconvenient accessory. For photometrically ac-curate measurements of footcandles or Lux,readings must be taken on a f lat diff used plane. Theflat diffuser supplied with the Luna-sphere makesthese measurementspossible, and withoutaffecting cal ibration ofthe instrument. Foot-candle measurementsare preferred by manycinematographers andlighting engineers.Others prefer to use theflat diffuser simplybecause it is moredirectional for incidentlight than diffusingsphere. The Luna-Sphere automaticallyadjusts the meter sensitivity when in use.

Spot Measuring AttachmentsBecause of its unique versatility, the Luna-Pro sbcSystem can readily cope with situations which

Accessories

make it desirable to use ref lected light measuringangles of less than the meter's standard 30'. Theseare two accessories which will decrease themeasuring angle for "spot" readings.

Multibeam Spot AttachmentFor even greater selectivity, the Multibeam @ SpotAttchment for the Luna-Pro sbc provide not only15" and 7.5" measuring angles but, in addition , a1"angle for ultra precise exposure measurement. Thesingle lens reflex design permits measuring andviewing through thesame lens, elimina-ting parallax Problemswhich can cause mea-suring errors with twin-lens 1" spot meters.

The Multibeam @ At-tachment focuses f rominf inity to 1.5 feet formaximum measuringaccuracy, and provi-sion is made for eye-piece correction. Withthis attachment, you

have the advantages of a separate 1 ' spot meter foryour Luna-Pro sbc, and it automatically adjusts themeter sensitivity when attached.

Variable Angle AttachmentThe modestly priced Vari-Angle Attachment locksinstantly onto the Luna-Pro sbc (or regularLuna-Pro) and provides convenient selection ofeither 15' or 7.5' measuring angles. For ref lectedlight readings, the normal measuring areacorresponds to a light acceptance angle of 30". Abuilt-in ref lex view-f inder showing the 15'and 7 .5" measu ringarea permits accuratemeasurements for ex-posures with telephotolenses and selectiveread ings of variousparts of the scene orsubject when' normallenses are used.

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Flash AttachmentElectronic flash has become an extremelyimportant source of controlled lighting in thestudio as well as on location. Previously, standardmeters designed to measure continuous light couldnot measure the short, extremely bright bursts oflight from such flash units. Now, however, thef lash attachment converts your Luna-Pro sbc into ahigh quality electronic flash meter! Employingmany of the engineering concepts of the precisionGossen Mark ll electronic f lash meter, thisaccessory can operate either as a cord-connectedor cordless meter to measure single or multiplef lashes.After the meter is turned on, any f lashes within atwo minute period can be measured and stored.Light emitting diodes indicate readiness andactivation. The two minute operating cycle can beterminated for individual single flash readings.When multiple flashes are required to achievecorrect exposure at a desired f/stop (e.g. forgreatest depth of field in interiors or other stillsubjects), the readings of successive flashes areautomatically accumulated within the two minutecycle to indicate to you how many flashes arenecessary for the desired result.32

Because, with this attachment, the Luna-Pro sbcintegrates and mea-sures the total f lash -not just the peak inten-sity it is accuratewith flash units havingvarying flash dura-tions. Measurementscan be made with dura-tions as short as1 / 100,000 sec. , mak-ing the meter suitablefor all commercial andamateur f lash units, in-cluding those withautomatic circu its. Theattachment automati-cally adjusts the meter sensitivity.

Microscope AttachmentThe Microscope Attachment utilizes the Luna-Prosbc measuring sensitivity for convenient and

reliable exposure measurement when taking photo-m icrog raphs. TheM icroscope attach-ment f its the oculartube of most micro-scopes for exact ex-posu re determ ina-tions, and is useful inmeasuring light inten-sity for fluorescentmicroscopy. Sensiti-vity adj ustment is auto-matic.

Repro [Copying Attachment]With the Repro Attachment on the Luna-Pro sbc, itis possible to obtain exposure values of flat copysuch as paintings, documents, and photographicprints.

The illumination on the copy board can bemeasured for evenness of various points on the

material to be copied.It can also be rever-sed for measurementsof light transmittedthrough slides or othertranslucent materialbeing copied.

Enlarging AttachmentThe Enlarging Attachment will help eliminateguesswork in darkroom printing. lt determinescontrast range andcorrect exposure timeby measuring the pro-jected image on yourenlarger easel. Aftercalibratiorfs for paperspeed, direct readingsof aperture and expo-sure times are pos-sible, resulting in sav-ings of time andmaterial.

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Fiber Optics Probe AttachmentWith the f lexible Fiber Optics Probe Attachment onthe Luna-Pro sbc, measurements can be made inmany areas which are usually inaccessible with anexposure meter. lt is especially suitable formacrophotography groundglass measurements,density measurements on negatives or trans-parencies, and for luminous density measure-ments. Sensitivity adjustment is automatic.

34

These accessories make the Luna-Pro Sbc the mostversatile and complete systems meter availabletoday. And, because it is a true system meter wherethe accessories interf ace with the meterelectronics, future advances in light measurementtechniques can be accommodated.

Appendix

lntermediateASA & DIN Values

lntermediateFootcandle Values

lntermediateF/Stop Values

ASA0.81

1.21.622.53

456I

101216

20253240

DIN01

234567

I9

1011

121314151617

ASA506480

100125160200250320400500650800

1,0001,2501,6002,0002,500

DIN18192021

22232425262728293031

323334,35

ASA DIN3,200 364,OOO 375,000 386,400 398,000 40

10,000 41

12,500 4216,000 4320,000 4425,000 4532,000 4640,000 4750,000 4864,000 4980,000 50

100,000 51

.016 .26

.o2 .33

.o25 .4

.o32 .5

.o4 .63

.05 .79

.065 1

.08 1.26

.1 1.6

.13 2

.16 2.5

.21 3.2

4 65 1,0005 82 1,2606.3 103 1,5908 130 2,OOO

10 164 2,50012.7 206 3,18016 260 4,00020 328 5,04025 413 6,35032 500 8,00040 630 10,08051 794 12,700

16,00020,16025,40032,000

.7 4551

57647281

90101

113128

2.83.2 13

3.5 144 164.5 185205.6 226.3 25729832936

10 40

*'

$

tt

.8

.91

1.1

1.31.41.61.822.22.5

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Your Gossen Luna-Pro sbcis your valuable precislon instrument, made with Oteat care and accurately calibrated. lt deserves your goodcare!

The battery and zero position tests described on page 5 enable you to check the proper functioning of yourLuna-Pro abc. lf meter is to be stored for extended periods of time, remove the battery from lhe meter.

Measuring comparisons of your Luna-Pro sbc with similar or other types of exposuro meters cannot be madeproperly without special laboratory equipment (optical bench).

Do not attempt to open or repair your Luna-Pro sbc. Service information appears on the following page.

36

SeruiceShould your Luna-Pro sbc require service, send the meter (directly or through an authorized dealer), in theoriginal packing if possible, prepaid and insured, to:

Gossen Service CentelBerkey Marketing Companies25-20 Brooklyn-Queens Expressway WestWoodside, New York 11377

Gossen Service CenterBerkey Marketing Companies1011 Ghestnut StreetBurbank, California 91506

A brief description of the reason for sending the meter should accompany the package.

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SpecificationsEVRange ........ ...... ASA25-O +15ResoonseTime. .... 'l / 1000 Sec.Photocell ..... SiliconBluecellAngleofcoverage ...... ....... 30'Reflected 180'IncidentSensitivity ...016to32,000footcandlesinonerangePower Source .9voltEvereadyBattery-orgvoltMalloryDuracell@AlkalineBatteryorequivalent.

Battery Type #M N1604Dimensions .. .,... 4t/tx13/qx23/tWeight . . . . . 8% oz. with battery

Scal€ Ranges:Cine Range ...... 4.5to 144tPs.Exposure Value Range... ...... -8to +24ShuttersDeeds .'. | /4,000 Sec. to I hoursLens Aoerture. .... t / 0.7 to 1 1128ExposureFactorScale...Plus/MinusexposureindicatedinEV; Plus exposure indicated in Exposure FactorASARange. ......0.810100,000

Additional Reference MaterialEastman Kodak Go.Kodak PublicationsRochester, New York 14650

KODAK Professional Photo Guide R-28KODAK Professional Black and White Films, 2ndEd. F-5KODAK Color Films, 6th Ed. E-77Sensitometric and lmage Structure Data forKODAK Color Films E-78Basic Photograph ic Sensitometry Workbook2-22-FDLens Extension Tables P-300KODAK Plates and Films for Scientific Photog-raphy P-315KODAK Filters for Scientif ic and Technical Uses,1st Ed. B-3

Stroebel, Leslie; View Camera Technique;Hastings House Publishers, Inc.; New York, NewYork 10016

Zakia, Richard and Todd, Hollis; PhotographicSensitometry; Morgan and Morgan, Inc.; DobbsFerry, New York 10522

Sturge, John; Handbook of Photography andReprography Materials, Processes and Systems;Seventh Edition; Van Nostrand Reinhold Co.; NewYork, New York 10001

Stimson, A.; Photometry and Radiometry forEngineers; John Wiley & Sons, Inc.; New York,New York 10016

Dowdell, J. lll and Zakia, R.; Zone Systemizer;Morgan and Morgan, Inc.; Dobbs Ferry, New York10522

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sOSS

4

EN'

Prices and Specifications subject to change without notice.

Gossen DivisionBERKEY MARKETI NG COMPANI ES25-20 Brooklyn-Queens Expwy. West,Woodside, NY 11377 t (212)932'4040

10'11 Chestnut Street. Burbank. Calilornia 91506 ! (213) 843-1883681GO 1077 Printed in U.S.A.