Twin Lens Reflex Guide booklet Product booklet

IOLOR





  Ansco Reflex . Argoflex   Bolsey C                          "
                                    Kenflex  Conloflex " Flexeret o lkoflex "
      Kodok Reflex " Penlq Reflex " Reflecto o Ricohflex
       Rolleicord " Rolleiflex oUniflex

7.  Twin-lens Reflex Charaeteristics

    Advantages of the Trvin-lens Reflex
        The efficient combination of adequate film size, portability, and
      maneuverability have made the 2L/a-inch size twin-lens reflex the most
     popular camera for black-and-white film, while the smaller Bolsey C
      reflex has become a favorite {or color. It is simple to prove by ele-
     mentary arithmetic that an BxI0 enlargement (a standard compari-
     son) requires only a four-time enlargement from a 27/a-inch negative,
      while an eight-time enlargement is the minimum enlargement required
     by the 35mm (lxlt/2 inch) size. Since 35mm color is usually pro-
      jected, conparison of enlargement sizes is not so critical because we
     view our projected images from far distances. In addition to its
      greater suitability for use with enlargements, ,5.2t/a-inch-square  size
    may be printed as contact size for use as a wallet or handbag picture.
     The color transparency from the 35mm size may be made into color
     enlargements (Printon, etc.) for similar use. However, these are only
      incidental advantages. Other features that have made the twin-lens
       reflex camera the favorite of exhibitors, magazine photographers, and
    many amateurs are:
                l.  Standard l2-exposure roll for black and whiteo or color
     (Ansco color has nine exposures), to let you see your photographs
      quickly; a 20- or 36-exposure color magazine of 35mm film requires
     a longer rvaiting period because you may not expose the entire film
      at one tinre.
I         2.  Direct focusing combined with instant viewfinding by means
      of a ground glass (an ideal focusing method).
         3. The camera is small, easy to carry, and always ready for
      instant picture taking.
         4. Uses a standard roll film (No. 120 or 620) available any-
     where in the world.
         5.  Adaptable for 35mm film, Bantam size, or cut film.
         6. The moderate enlargement required (4X ) for an Bx10 pic-
      ture minimizes the need of fine-grain development. A medium-grain
      developer is adequate, and also has the added advantage of producing
      the fullest emulsion speed.



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7.  114.5, or faster, lenses are available. The viewing lens is
faster than the taking lens, to permit easier focusing.
    B. The square format permits composition in any one of three
pleasing patterns: square, vertical, or horizontal. This allows better
picture composition.
     9. The 3-inch lens of short focal length has a great depth of
field and hyperfocal distance. The sharp image that is so produced,
for most part or middle distances, lessens the need for continued
critical focusing.
    10. The 3-inch lens, used with 35mm or Bantam film, produces
a semitelephoto efiect. The perspective so produced is iileal for por-
traiture because the image has pleasing naturalness.





          Unit-focusing Comero                  Twin-lens Reflex Cufqwoy View

rt.  wide-open focusing is possible at all times. The top-viewing
 lens is always at its brightest, clearest, and widest opening. Thi, i, i.,
 direct contrast to the single-lens reflex, which must be stopped down
 just before an exposure is made. The continuous wide-open efiect also
 saves the momentary loss of time that occurs with a sirrgle-lerrs reflex,
 in which the mirror must be swung completely out of the way of the
 lens-to-film line. Because the momentary swing of the mirror blocks
 out the field of view, there is always un ,rrr."riainty as to the results
 of the shot.
    L2. The between-the-lens shutter used on all models is trouble-
 free, easily synchronized-for any flashlamp or flashtube, and may be
 used with a solenoid (which releases the shutter electromagnetically                                                           ""*oo.o," *                tilfr   '%.ut:iru;                 i*,"ffi);ameras have auromatic
 stops to eliminate the need for constant reference to the red counting
 window.
    14. This type of camera is easily adaptable for studio, portrai-
 ture, copying, medical, and scientific photography.

The Safe-Set Method
    The Safe-set Method has been developed by the author from ex-
perience in lecturing, writing, and teaching begin.re.s to learn to use
a camera expertly. It is founded on the two cornerstones of stantJ-
ardization and pre settitt g :
       I.  Standardization is essential for the confidence that one feels
*hg  using one film, one developer, one flashl&*p, etc., of known
performance.
    2.  Presetting_ is the crux of the Safe-Set Method. Just as equip-
ment must be standardized, so must the procedure of taking u pi"ir*.
Such variables as shutter speed, apertrire, focuso and efi-ect can be
preset and controlled with this method. you simpry select your subject
size, choose and set its co-ordinated distance, iri-s, and shuiter settings,
and at the peak of effect, snap the perfect picture.
    since outdoo.r lightin-g is usually ,.rrifor* throughout a large
area, the iris opening and shutter rp""d (siandard ized, ait 1so ,""orrf;
are n€ver changed, once t!"I have been set for the basic exposure
permitted by the light available. The Safe-ser chart is used to show
what distances will be needed for the difierent bodv sizes.
    However, this applies under the conditions mentioned and not
when the iris opening and shutter speed are synchronized to flash.

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How the Sale-Set Method Helps You
     The use of the Safe-Set Method for taking pictures with all twin-
 lens reflex cameras is recommended because:
       I.  All troublesome camera variables are eliminated. Every pic-
 ture-taking factor is preset. There are no last split-second fumbling
 delays to correct controls as the camera-to-subject distance changes.
     2. Each frame is completely filled with the entire subject. All
 black-and-white negatives from a roll can be enlarged to a uni{orm
 size without any need for raising or lowering the enlarger after the
 initial enlargement ratio has been chosen and column height has been
 set.
     3.  All color exposures are so uniform that they project with
 equal quality and do not require different enlargement exposure times
 for Diaversal prints made to a uniform size.
    4.  Flash shots can be taken only with the safe-set Method be-
 cause your exposure is directly related to the camera-to-subject dis-
 tance. To get a perfect picture it is necessary to safe-set all controls
 and to keep your camera-to-subject distance constant by moving with
 the subject.


The Sale-Set Chart
    The Safe-Set chart is the heart of the method because it gives
you at a glance any information you may need. It eliminates com-
pletely the necessity for calculating the aperture opening for flash
pictures. For example, let us work out a chart for the use of SM or
SF flashlamps with black-and-white film A.S.A. 50. (Data charts for
other lamps and films will be found at the end of the book, page 125.)
The chart should be written on adhesive tape or some similar material
and pasted on the back of your reflector. For the purpose of this
example, first check the following:

                                     Shutter
        Lens        Film, B&W' Speed    Flashlamp
    3-inch focal      A.S.A. 50   Ll25    SM, No. 5
       length                               or SF No. 25
  Then, add four lines for the four most frequently used subject
sizes. Each line is divided into focusins distance for that size and
4

for the lens iris opening required with the flashlamp for that particu-
lar distance.
    The completed chart will look like this:

                                                        opening Subject size           Distance     I  Iris (tl)
 Full body
 Three-quarter body
 Head and shoulders
 Head
   When the chart has been pasted on your flash reflector, this is
how it should be used for flash:
      If a full-length picture of a number of people is desired,
then we scan our chart for the full-body line. It tells us that {or black-
and-white film, with a shutter speed set for Ll25 (this speed synchro'
 nizes with all flashlamps and flashtubes), a full-body picture can be
taken at l0 feet. So, we set our focusing scale at I0 feet. Never alter
 the focus setting; one turn of the knob changes the focus considerably.
With the SM or SF lamps, lens opening for 10 feet is between fl9
 and f/Il;  rotate your lens setting until it is opposite the index mark.
Now, everything is safe-set. After you have checked the shutter to see
that it is set, you merely walk toward the subject while looking
 into the ground glass. When your image is sharp, compose your pic-
 ture. and release the shutter.




                               The Sofe-Set Chort Printed on Adhesive Tope
          *&#.                 #};                 ond Altoched to Bock of Flosh Refleclor                -  {*.W    el.# .fti
   ffi,,...,..,,,.
Using Safe'Set Outdoors
     Presuming our light to be constant, let us start to set up for out-
door picture-taking. First, it is recommended that you use a daylight-
                                                                         thattype lolor film (ih" manufacturer processes it Jor you), so
i*       defer darkroom work until you have had some picture'    "u"
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Distarrce, Action, and Landscape Scenes
     Proceed as follows:
       l.  Load the camera with film following the instruction booklet
that came with the camera or by having the camera store salesman
 assist you.
    2.  Set your distance scale at 30 feet for distance areas, or 12
 feet for medium close-ups if you want to take action shots.
    3. For color film, set your aperture indicator to the space be-
tween B and 5.6  (f 16.3). For an A.S.A.50 biack-and-white  film, set
the indicator between 11 and 16. Set your shutter speed at 50. Cameras
that have double-action shutters must first be cocked before they can
be released. Single-action shutters, such as those in the Argoflex and
the Bolsey C, do not require cocking because the releasing motion
simultaneously cocks the shutter for the release.
    4.  If the blue-lamp flash is to be used for an outdoor fili-in
light, then use a basic setting oI Il25 at Il9.
    5.  Hold the camera correctly and firmly at waist level.
    6. Keep your eyes focused on the ground glass and look at it.
not througft it. You will see your subject on it (but much smaller than
it actually is), and as much as vou see of it, to that extent will you
get it in your final picture. If your nearest subject is kept 15 feet
away for the 30-foot setting, and between 9 and 15 feet for the l2-foot
distance, the picture will be sharp. Note: The top viewing lens is wide
open so that it does not always show the full area of sharpness. Be-
cause of this, the ground glass should be used only for composing
when large area settings are used.
    7. When using color film, it is best to wait for that kind of day
when colors will be most brilliant. Colors will photograph best on a
clear, sunny day. If the sky is dull and overcast, your final pictures
will also be dull and overcast. You will find that the camera controls
described here are correct for a bright day. For other lighting con-
ditions, which can produce interesting effects but require greater care
in making the exposure, consult an exposure chart or use an exposure
meter.                                                                                --_r.-j..
Outdoor Subjects ol Definite Size
    The setting for pictures of subjects having a definite area, such
as a full body, head and shoulders, or groups, is difiefent than the
usual 30- or l2-foot setting used for landscapes. The chart on page 109
shows the various field sizes for these distances.
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Using Safe-Set Indoors
             If the weather is so poor that there is little light availabie, or if
      your picture is to be taken indoors, you can become totally independ-
     ent of outdoor light through the use of indoor color fiim and an
      accessory flash unit. With flash, you must remember that the syn-
      chronization of the flash and shutter takes place only at certain speeds
      because the duration of the light flash is so brief. The Ll2l-second
      shutter speed is a standardized safe choice for all cameras because it
       will synchronize with all lamps. Even though the shutter speed is 1125,f,      the brief duration of the flash (L1200 second with SM or SF lamps)
f'     will stop the action because the picture is taken only as long as the
       light is on.

     Procedure lor Flash Pictures
il,      To use your camera for flash, follow this simple procedure:
        1. Refer to the Safe-Set Chart and check your film and equip-
     ment adjustments.
        2. From the chart preselect the subject size and subject distance.
        3.  Set your distance scale.
        4.  Choose the aperture for this distance from the chart, and set
     your carnera lens iris to it.
        5. Now approach your subject to the approximate distance that
     has been set and then look at it on your ground glass. If the image
        is not sharp, move back and forth until it is. Do not touch the focusing
      lever. If you do, ycu will find that you have turned your scale a
      considerable distance, even with a half- or quarter-turn of the control.
       It is far more accurate and easier to move the safe-set camera to the
     point of accurate focus than to trv to get the image in focus by
     turning the focusing controls.
         Note: Even if you are a few inches in front of, or behind, your
      actual distance setting, the image will still be sharp because the depth
     of field adequately compensates for a slight variation in distance.
     (See Chapter 4.)
       When you are satisfied that the'image is in sharp focus, compose
    your picture, wait for the peak of action or expression, and then
     squeeze the release. A click of the shutter and the flash of a lamp
       tells you that the flash picture has been taken.
          After taking your picture, wind the film immediately to the next
     frame only it you are going to take another picture. Otherwise, the

film may lose its rigidity and buckle. Buckled film produces an out-
of-focus image in spots because it is not flat on the focal plane of
sharp focus.
    The less expensive cameras have a red window for use as an ex-
posure indicator; the more advanced have automatic exposure count-
ers; while the most advanced (Automatic Rolleiflex) winds the film
and sets the shutter at the same time. When the entire roll has been
taken, continue winding your film until you hear the paper backing
flap in the take-up spool chamber. Note:35mm film must be rewound
into its original cartridge. (The Richoflex is an exception.)
    6.  After opening the back, remove the film by pulling out the
knob that holds the take-up spool. Keep a firm grip on the paper
backing and bend the paper end under so that the adhesive label may
be wrapped around the roll to seal the spool.
    7. Mail your film to a processing center after carefully ad-
dressing the shipping tag and checking the amount of your postage.
The returned, processed color transparencies or prints may be viewed,
enlarged, or projected.

The Key to SAFE Pietures
    The instructions given for using the Safe-Set Method are simple,
and they will produce a picture each time. The time to remember all
the picture-taking factors is belore the exposure is made. As an aid
to memorizing these important points so that you can check them,
recall the word SAFE before you take a picture: S-shutter; A-aper-
ture I F-focus; E-exposure.
    Your camera is a flexible instrument, capable of many changes
for use under varying light, shutter speed, and distance conditions.
For outdoor shots, the only judgment required is the choice of a
bright, sunny day, preselection of your distance and/or your subject
size, and retention of the subject within the permissible distances from
your camera. Learn to safe-set your camera controls for either in-
doors or outdoors, and you can be sure of fine results.
    Note: Shutter speed is I/50 for a No.5 or No.25 lamp.
   When taking indoor pictures, the Safe-Set Method practically
takes the picture for you.
    Chapter 2 (S, A, F, E) will show you how to change the simple
settings of the Safe-Set Method to meet all possible conditions or
requirements.
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2. The Safe.Set Method Applied

                  S: THE SHUTTER
How the Camera Shutter Works
    The flow of light through the lens of your camera is controlled
by the shutter and the iris diaphragm, just as the regulating knob on
the water faucet controls the size and duration of the flow of water
through the faucet. The iris diaphragm controls the "size" o{ the
stream of light, while the shutter controls the length of time the light
is permitted to strike the film. Exposure is a product of the two-iris
diaphragm and shutter control.
   When the shutter is opened, light that is entering through the lens
will reach the film. If the shutter remains open a long timee more
light will enter through the lens than if the shutter had remained open
for only a short time.
    The volume of light available determines whether  it is necessary
to leave the shutter open for a long or for a short time. When the
volume of light is very low, you may be required to leave the shutter
open for as long as an hour or more (time exposure). If a large
amount of light is available, on the other hand, a sports or action shot
may be taken in as little as 1/500 second to stop the fast motion of
your subject.
Shutter Speed jvtK-'g
   From the motion chart, you can choose the correct shutter speed.
You will find later that, if a choice of speeds is permissible, the slower
speeds will allow the use of a narrow iris opening, which realizes a
guin itr over-all sharpness, while a faster speed requirys a wider
opening, which will produce a shallow depth of field. The correct
choice of iris opening, which depends on your shutter-speed selection,
may often be an important point in making or breaking the efiect of
a picture. As an example, landscapes usually require a narrow open'
ing to produce an over-all sharpness; therefore a slow shutter- speed
is used. A portrait, on the other hand, may require an out'of-focus
background; therefore the wide opening needed requires a rapid speed
                                                                   11

setting. Action pictures naturally require the fastest speed of your
 twin-lens reflex to stop the motion-I/S0O  second.

         SHUTTER SPEEDS FOR MOVING SUBJECTS
                       LINE OF N{OTION
 SUBJECT AT 25 FEET                                  lJ                   \           3;
Valking at I miles per hour      r/r0         r/100           L/ L'O
Children playing                    L/ r00        r/2oo        r/300
Street accivity                        L/ rco        t/200        L/300
Swimrners, skacers                    r/ rcO        L/200        r/300     *
Vehicles ac 2A m.p.h.           L/200        r/400          * t/500
Football, running               L/200        t/4oo           * L/500
Vehicles at 40 m.p.h.           r/400        t/500          * t/500
Tennis                      *t/500        r/500                                                                                    * L/500
                                                                                          * t/500Horse race                    *7/500          * Uroo
,{irplanes                                  * 1 /500          * 7/t00           * t/100
N.ts. When your subiect is at ,0 ft., multiply att speeds by                     dl
      2(L/ r00x2= l/50).
     For 100 ft. subiect distances, multiply all speeds by             * ,   4(1/r00x4=l/2r.                                                                                                                                                  f'    *PAN             to stop motion.
                                                                                                    #t Shutter-speed Rule for Beginners
      Still (inanimate) subjects may be taken with the slowest speed
 available, Yz or 1 second, or even B or T, to secure the greatest amount
 of subject sharpness by stopping down the lens (i.e., using a narrower
 iris diaphragm opening).
     Living (animate) subjects require a fast shutter speed of at least
 1/50 second. To be on the safe side, sports or action pictures should
 be taken at the fastest speed that your shutter has to be certain that
 the action is stopped. Standardize all {ast shots at 11200 Alphax,
 1/300(SV), Il40O Rapax, or I/500 (Comiiur).
       If an exact shutter speed must be determined for a subject in
motion in order to use the smallest opening possible, you can re-
member what speed to use by knowing the meaning of the series of
 numbers, 25,5,25. This basic number group means that, for a subject
25 fieet awal, moving at 5 miles per hour, with a line of motion
 directly toward or directly away {rom the camera, the shutter speed
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need be only Tl25 second io stop its motion without a blur. A 45-
degree line of motion requires a double shutter speed of 1/50 second,
while a 90-degree line of motion requires a triple speed, or Ll75
second. If a subject's speed is increased to l0 miles per hour, then all
numbers are doubled in proportion: I/50, I/100, I/150, etc. If, on
the other hand, the subject distance is increased to 50 feet, all speed
numbers may be halved. With a 100-foot distance the numbers are
divided by 4, so that a subject moving at20 miles per hour, 100 feet
away, with a line of motion toward a camera still requires a Ll25-
second shutter speed. The decrease in exposure time is due to the
faster speed of your subject.
    Write the computed numbers on a piece of adhesive tape or
similar material and paste it on your camera case for ready reference.

Supplernentary Techniques

Panning
      If your highest shutter speed is still too slow to stop the motion
of a rapidly moving object from a set position, then you will have to





      Setting the Shufter Speed                     Cocking the Shutler
                                                            t3

I

.'pur"      your camera to stop the subject's motion. Panning-means that
yl.r r*ing or move the camera in the line and direction of movement.
                                                                      theThis is glnerally done by swinging your camera in an arc as
subject -ou", past you in space. When you snap your shutter underthese conditions, the subject will be in sharp focus, but the back'
ground will be blurred. While this is not always the best photographic
iechnique for over-all sharpness, the resulting sharp subject, which is
the essential purpose of the picture, fully justifies the compromise.

Hand-held Exposures
    The li$Q-second setting, or faster, is the slowest speed recom'
mended for a hand-held exposure. All slower speeds should be taken
with the camera on a triPod.                                                                                                                                                                              'l
                                                                     a   we magnify our pictures by enlargement, projection, or in
special viewer in order to see them clearly because the film size is
smatl. Unless the camera is held firmly, body vibration or tremor will
be transmitted to it, and when magnified, will show on the picture as
an over-all blur. At speeds slower than I/50 second the camera may
be hand-held only after special training; but after such training, even
 1/I0-second speed can be used.
    To limit ihe possibility of blurring the picture with a hand-held
camera, brace yourself in this fashion:
     Place yorri feet so that your toes are approximately 4 in_ches apart,
your heels about 6 inches apart.- Hold your,camera firmly. Take a
 h""p br"uth and exhale. Shortly after the exhalation? you- will find- that
 you are at your steadiest. Ai this point release the shutter with a
 smooth, uniform motion.
      wirit" this method will yield good pictures even at I/l0-second
 speed, it is {ar safer to use a tripod so that camera movement will be
            at speeds slower than 1/50. If no- tripod is available, you -ini-ir"d can steady the iu^"ru on a tree, an automobile, a wall, a fence, etc'

 Camera-steadY Control
      Practice releasing, or cocking and releasing, the shutter a num'
 ber of times. Some ,"i"ur" levers d"pt"tt more than others before the
 shutter is activated. Practice to get the experience with your particu-
 lar twin-lens reflex camera so that you will get the pressure for the
 depth of release just right. Correct rlleasing pressure is important for
 ."iion pictures and baby portraits that require.split'second timing to
 capture the once'in-a'lifetime expression or action'
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best placg to practice releasing the shut-                       .The                      ter is in front of a lar_ge mirror. Stind fairly
                      close and look through the viewfinder as yo, ."-
                       lease the shutter. Any slight movement that you
                     notice would have occurred had you actually
                     taken a picture. Jerking the camera rel"us" *orrli
                    have produced an unsharp picture had there been
                       film in the camera. Practicl, therefore, ,rrrtil you
                    see that the camera remains rock-steady durirrg
                     the exposure.
   Releosing the Shutter
  Eliminating Vibration
     cable Release,. Another important aid for minimizing camera
 movement is a cable release. It is useful if your camera i, orr"a tripoJ.
 should your finger p_ress against the releas" too strongly, th" vib.uiio'
 would be transmitted to the camera through your hand. with a cable
  release, however, your hand is free und      of the camera, and the                                            "I"u. pressure and the vibration cannot reach                                                           it. we recommend a long
 cloth-covered cable release for best results. It should be looself l;";;:
  If it is stretched taut, the releasing action may still be transmitted to the camera.
      Delayecl-action Selt'-timer. If a cable release is not available and
 you are fearful of vibration in releasing the shutter, then yo,,       ,rr"
 a self-timer to release the shutter. Rofl"i, and similu,      "u"hur"
 integral (built-in standardized,), delayed-action self-timer*,"u-"ru,*rrir" irr"
 less expensive model._Tuy have a removable type that can be added
 whenever necessary. The removable type must'be designed pr;iJy
 and adjusted carefully, otherwise youi ,hutt", can be broken.
    The cable release or delayed-action self-timer is mandatory when
 takin_g macro- or micro-close-ups.
     In use, you will find that on"" the delayed-action mechanism is
 set and released, there is about a lS-second delay before the camera
shutter is released. within this time tripod vibration will usually
cease so_that your pictures will be sharp.
    Delayed action t'or Flash. This lS-second delay also provides
sufficient time for getting yourself                               a picture. you safe-r", y"",                                    _intocamera, release the self-timer, and get inio the picture before the
flash goes ofi.
      If you will look into your picture album you will be surprised to
                                                             t5

find so few pictures of yourself because you have usually taken pic-
tures of others. With a self-timer, your family groups or friendship                     I
circles will be complete since you will be included.
Speeial Types of Shutters

Between-the-lens  Shutter
    The shutter speeds of a typical synchroshutter are T, B, L,2,5,
L0, 25,50, 100, 250, and 500. These numbers refer to fractions of a
second. The 50 means Il50; the2 means Il2;  etc.7 (time) requires
two clicks of your release. The first opens the shutter and keeps it
open, while the second closes the shutter. The B (bulb) setting will
keep the shutter open only as long as there is pressure on the release.
Use the B setting f.or 2- to S-second exposures. 7 is used for longer
periods of time.
      If your shutter has only a B setting, you can get a I  effect with
a special locking cable release. This type is built with a set screw or
automatic clamping disk to hold the plunger in place so that the
shutter leaves will remain open even at the B setting.
       It is best to set your shutter speed directly opposite the engraved
numbers.
    In double-action shutters, the shutter is cocked as the first action
by moving the cocking lever until it clicks. Now, you are readv for
the exposure. The second action releases the shutter.
    Caution: The I/500-second speed setting must be made belore
your shutter is cocked. Do not attempt to move your speed dial to
l/500 second after the shutter is cocked. To do so is to invite trouble.
It is better to lose a frame by releasing the shutter, winding to a new
frame, and then resetting the shutter for l/S00-second speed.
    Speeds other than 1/500 may be changed, but it is best to plan
your shot beforehand and leave the speed setting alone after the
shutter has been cocked. Remember, one exposure costs approximately
four cents while a broken gear may cost many dollars to repair.
    In single-action shutters (Alphax, etc.) one-lever motion cocks
and releases the shutter simultaneously. The speed range is usually
I/10 to Il20O second.

F lash-synchr onized, Shutters
    Typical flash-synchronized shutters are the Rapax, Synchro'
Alphax, Prontor SV, Compur X, or M-X. While they vary in top
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shutter speeds, all flash-synchronized shutters perform equaily well.
            Sale-Set Constant Shutter Speed. Although the shutter speed,l       remains constant, the iris opening varies, according to the light con-
        ditions, as follows:
                        I/I00  sunny day    IlLl
                   r/I00 bright day  IIB
                    Iif00 cloudy day  f15.6
                   r/r00 dull day    fl4
       A large range of shutter speeds, while irnportant for highly spe-
        cialized work, is not needed by the beginner. This was proved when
       a survey o{ salon prize winners showed that the average speed setting
      had been l/100 second. With this fact in mind, the beginner can see
        that speeds up to fi 100 second will suffice for most of his pictures.

                   A: THE APERTURE (IRIS)
    What the Aperture Does
        When a faucet is opened, water flows through it for any desired
       time. A narrow faucet opening lets a small amount of water come
       through, while a large opening permits a greater volume to flow. The
       relationship of the diameter of the faucet is similar photographically
       to the size of the lens opening.
           In order to know the relationship of the opening for the purpose
        of calculating an exposure, a number is assigned to various diameters.
       This number is derived by dividing the diameter of the opening into
       the distance required to form an infinity image. If the lens forms an
       infinity image when it is 2 inches distant from the film, and the
      opening is t/2-inch wide, the lens will be marked f.lA for that diameter.
         If the opening is l-inch wide, then 2lI-112. A small number indi-
       cates a wide opening, whereas a high,number indicates a narrow
       opening. The wider the opening, the greater amount of light that is
       admitted at a given interval o{ time.
           Conversely, the narrower the opening, the smaller the volume of
        light that can reach the film within the time that the shutter remains
      open. For completely equal exposures, ]ou can have either a large
      opening and a fast shutter speed or a narrow opening with a slow
       shutter speed. Each combination has different advantages. A wide
      opening permits short exposures, such as is necessary for action pic-
                                                                     L7

Rnr,errvs LIGHT rNcREAsE, IF oNLY THE
Fur,r--srop MARKING                      IRIS IS WIDENED                                                                                       I
                                                                               a       f/r                       I       These are full stop openings with                                                                      transmission                f /L.4                   2      rc\% difierence in light
       f/2                   4       between two adjoining stoPs.
                f /2.3                   B           If the indicator is moved approximately
         f./4                    t6         half way between the two markings, the
                f /s.6                  32           iris is opened r/2 stop and the difierence       f/B                   64        in lighf transmission is increased 50/o.
                f /LT                t2B       Half way between f/5.6 and f/B Pr9'                                                                                                                                                                                     f /9.       r/L6                256        duces f/6.3, between f,/B and f/11 is

Her-r-srop oPENINGS
                f /3.s                        I       These specific-in    numbers produce -",4t1--       t/4                            l\/t       ference     light lransmission of 50/o
         f./4.s                    2        from one mark to another.
        I/s.6                   3
                  f /6.3                         AL/z
         r./8                    6
       f/e                   9
         T./LI                   t2
         f./12.s                 IB
                  f /L6                 24
       T/IB                   36
                  f /22                  48
                                      shutter speed is changed lrorn I/I0o tox_g. Euerything being equal,                                                                                   if. .the       11200, the iris must be widened,one s-top'^             .I                                                       i'-        lrom r/i00 to r/50, the iris is narrowed       if;;   ;i;,;;;      one stoq.        ':;";;;   "ilni"i
         If the'shutter speed, is changed trom I/f00 to l/75, the shutter is nar-
       r'owed by a/z stoq.
          Il the shutter ii narrowed lrorn I/B .to I/L6, the shutter sPeed, is length-        ined, four times so that L/100 wiII be re-set to I/25.
 tures or where a slow-emulsion film speed requires large amounts of
 light {or an exposure. With a wide opening, the subject will usually
 bJ ,harp within a Iimited {ront-to-back distance. A narrow opening,
 on the nth"t hand, will produce subject sharpness in far deeper areas
 of the picture.
    $h"n a sharp image is desirable, but not always possible, _com'
 promise by getting what you can, with at least your main subject
 absolutely sharP.
     The iris diaphragm of a lens regulates the size of the opening for
                                                                                   to_ the admitting light to thi film. The iris is similar in many- ways
 iris of the human eye. If you look into a mirror and bring a liglt
 close to your eyes, you wili see that the iris opening narrows. As the
 light is moved-away, the iris widens. You duplicate this narrowing
 uid *id"ning with the diaphragm of your lens by moving the iris'
 IB

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openrng indicator from the higher to the lower number. I{ you will
        look through the back of your camera and then through the lens, you
         will see the similarity as you narrow and widen your lens opening.
          The numerals fl2.B, Il4, f.|5.6, ff B, etc., represent a L00/s dit-
        ference in light admittanc e;  t l4 to f.15.6 represents a L00/o reduction;
         115.6 widened to fl4 represents a L00/o increase.
           Rem,ember; The narrower the opening of your lens, the greater
          will be the depth of field. Narrow stops give great depth of field. Wide
        stops yield very shallow areas of sharpness.

     The Safe-Set Constant fris Opening
                It is possible to safe-set your iris opening and keep it at a
        constant size for all lighting by varying the shutter speed to compen-
       sate for the difierence in exposure that would be needed when
       changing from dim to bright light. A constant iris setting is necessary
           if your depth of field must be uniform. Otherwise, widening or nar-
        rowing the opening changes the depth of field. To use the iris Safe-Set
       Method, e.g., for an average subject (Class 2 olthe exposure chart on
        page 30), the opening is set for:
4                                fllL  sunny duy 1/100                                          1'                                              f ILI  bright      Ll50                                             c'                                           tlll   cloudy     Il25
                                   tlll  duil  "   1i10





                                             Setting fhe lris

       Using Lens ot' Short Focal Length
        An inherent quality of a 3-inch lens of short focal length is its
       remarkably large depth-of-field area of sharpness for the negative
         size, even when the iris is wide open. This short lens at flL has the
                                                                      19

same depth of field as a 6-inch lens at f.l9, or a l2'inch lens at f.lL6.
When your light is constant, this knowledge is very valuable. With a
3-inch lens set at f.14, you will be able to get a picture that has ade'
quate depth under certain set minimum lighting conditions. Since a
lens of longer focal length would require an opening of. f.lL6 for the
same depth, your picture would be either hopelessly underexposed or
you couldn't take a picture at all because the exposure would have to
be 16 times that at  f l4.The depth of field possible with a lens of short
focal length at a wide opening is often the critical all-important
difierence between a bad and a good picture.
   Now you have learned two of the four SAFE rules-to set your
shutter and to control the variable opening (iris) on your lens. F and
E are next.
                  F: FOCUS
Sharpness Depends on Good Focusing
    Focusing is the process of ensuring the maximum amount of
image sharpness. The correct subject-to-camera distance may be esti-





  (Top) Prismolic Focuser. (Bottom) Focus-
    ing Scole ond Depth-of-Field Scole
                                                        Focuser on lkonflex
20


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mated in a number of      such as using your ground grass (when                               -*lyr,       precise focus is needed for portraiture oi fo, nin.y, .rri.g u Fo"r,)      spot photo-optical device (Kalart) fo_r press work, or by silnply esti-
      Tlt]"s the distance for use with the hyperfocal distance o. depth-of-
        field effect. To make an accurate estimate, take advantage of'either
      the depth-of-field or hyperfocal-scale settings. These latter terms will
     be described later in greater detail. Read lhi,  fo"rrsing information
       carefully. A sharp focus is a necessary basis for a gooi picture.
                                            B- or Byslin"hio"ul iength        ,    Because_ your camera lens of eitirer
      has a gr:1! depth of field, your images will be sha"rp from irrfini-ty-to
      most middle distances without requiiing any further critical fo"r.irrg.
      Because your top viewing lens has a w-ide aperture,  it will show less
      of your subject in focus than if the iris rvere stopped smaller. you
     must remember this when the hyperfocal o. d"pih-of-field scale is
      used, bec-ause your taking lens is siopped down, wen though the top
     viewing lens is opel. The aperture difierence between thl top ani
     bottom lenses rnust be remembered for another reason: background
      objects viewed thro 'gh the viewing rens may appe ar fuzzy, b"ut will
     photograph sharply due to the nanower stop r."i.

     Tn'in-lens Reflex Svstems
        The focusing systems of twin-lens reflex cameras can be divided
      into two classes.
              l.   unit Focusi.rtg.- Both top-viewing and bottom-taking lenses
     are mounted on a single moving lensboaid. The complete uiit that
     holds both lenses moves backward and forward as the image is
      focused.
        2.  Front-cell co-ordinated Helicle Focusing. Both top and
     bottom lenses are mounted in a nonmoving lensbiard and trriy
     focused together by turning one of the g"ui"d lensfronts. The rrlti"l"".L
    mounts are so co-ordinated that when one is turned the other rotates
     as well. The optical method is such that only the front elements of
      the top and bottom lenses turn on each ot}er.
                 45 has a rotating taking lens, which focuses by         -The _Argoflex
     turning the front element; but the top lens does- not focus,
     only for its viewfinder efiect                                            ""r,rirrg
       The lea,.t expensive twin-lens reflex types are essentially fixed-
    focus box cameras. No adjustments are urruilabl" for distance. For
     best results, the fixed-focus box camera types (Argoflex z5) must be
                                                                   2L