Why umbrella? — photographic lighting Reference guide

WHY UMBRELLA?


           by Bill Norman





           ovER 250,000 coPtES
                     IN PRINT



@ Copyright 1970 - Norman Enterprises, Inc.

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       WHY UMBRELLA?
     In recent years, umbrella bounce lighting has become increasingly
 popular in almost every phase of electronic flash photography. Although
 no particular lighting technique will solve all your lighting problems,
 umbrella bounce light has true merits which you may find very useful.
    The purpose of this report is to familiarize you with answers to the
 questions most often asked us concerning umbrella bounce lighting.
We hope you will find this information valuable for your particular type
 of electronic flash photography,
    Your questions and suggestions are always appreciated at Norman
 Enterprises, for they enable us to improve our products and to meet
 your continually changing needs.

    WHAT ARE SOME OF THE ADVANTAGES OF UMBRELIA
         BOUNCE IIGHTING OVER DIRECT TIGHTING
    Umbrella bounce light is a softer light than most direct light. This
soft effect can be created in ways other than umbrella bounce, but in
most cases the other methods are not as portable or as practical as
umbrellas. For example, many soft light lampheads or bounce flats are
too large to use on location; also, wall and ceiling color encountered on
 location are not always correct for bouncing light.
    This soft light is generally desirable for high key photography where
shadow areas are kept to a minimum. Much of today's low key portrait
photography is done with umbrella bounce light because light placement
is uncomplicated and skin tones are quite flattering.
    Umbrella bounce light produces a larger, more even angle of cover-
age than most direct light units. This can mean that light placement  is
less critical, especially in situations such as fashion and some commer-
cial photography where your subject is moving over a given area.
    Umbrella bounce light tends to wrap around the subject and in
many instances, this reduces the number of lights required to create a
particular effect. Also, umbrellas can be utilized to simulate the "north-

---/--=/-'
              l-      ---\---\\.-_                                                                                      I                                                  \//
                UMBREI.LA  B()UTICE LIGHT TINI)S T() WRAP AROUI{D THT SUEJTCT.
                                                       Fig. 1
 light" effect and thereby minimize retouching.
     In small shooting areas where you are not able to move direct light
equipment back far enough to obtain adequate depth of light, umbrella
bounce light is especially handy. Maximum depth of light penetration
 is possible because the light fall-off (inverse square law) is measured
from the light to the umbrella, then back to the subject.





                      tlg.2                                                     Fig. 3
             I|l, FR(,M TIGHT T(l SUBJECT                    10' FR()M TIGHT T(l SUBJTCT rf,Y()U }IEED AI{ 8,SPACE.                  YOU NTEI) A I(1, SPACE.

   WHAT ARE SOME OF THE DISADVANTAGES OF UMBRELIA
         BOUNCE TIGHTING OVER DIRECT TIGHTING?
    In situations where depth of field is to be maintained, umbrella
bounce lighting generally requires more light output from your elec-
tronic flash unit than you need when using direct light. This is due
to the light losses in the umbrella fabric as well to the increased angle
of coverage obtained from bouncing the light. ln many cases this means
that the electronic flash equipment you need will cost more because
of the additional power required to work at a given f stop. However,
since you may not require as many lampheads to create a particular
effect, your overall investment in equipment may be similar for a direct
or umbrella bounce system.
    Umbrella light is not practical for many situations where a high de-
gree of contrast and control is needed. This would be the case when
using barn doors, snoots, spot lights, etc. However, in many of these
instances, umbrella lighting may still be utilized as a fiil light source.
                         -2-

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    Umbrella lighting does not lend itself to situations such as outdoor
shooting on windy days, or to candid work where you have neither time
nor space to set up a light stand and umbrella assembly.
    In some cases modeling lights are not bright enough for use in
umbrellas and it is difficult to compose lighting and focus the camera.
This problem has been solved in many instances by the use of high
powered quartz modeling lamps.

           CHOOSING THE PROPER UMBREILA
    There are round umbrellas, square umbrellas, white umbrellas, silver
umbrellas, large umbrellas, small umbrellas, umbrellas designed to
change color balance, and every combination imaginable. We have no
stock answer designed to recommend which one you need, but rather
feel an intelligent decision should take into consideration the equipment
you will be using and the effect you desire in your photography.

          WHAT ABOUT ROUND UMBRETTAS?
   Round umbrellas produce' round catch lights. In most cases the
catch light looks completely normal. lt is sometimes possible to see
the actual shape of the umbrella perimeter in the catch light. This
could be desirable or undesirable. lt's all a matter of personal prefer-
ence.
    Round umbrellas generally have curved ribs. The angle of reflection
is less near the edges of the curved ribs than it would be near the edges
of flat ribs, thus you get a greater wrap around effect than with flat
ribbed umbrellas. This added wrap around effect is very desirable for
color portraiture. The resulting soft light requires little or no fill light,
depending on the desired effect. The curved ribs also enable you to
feather the light with more control than with flat ribbed umbrellas,
because the angle of coverage has a more defined cut off point.
                               -"/
                                 ,/"
                                                        ),)                                \--
                                --\
                                                          tll. 4
                                CURVEO RIBS
                             WRAP THE IICHT
                                  AR()UND IHE SUBJECI
    In some round umbrellas. the curved ribs can cause the reflected
light to produce a focal point. This focal point could be undesirable

when using the umbrella at a distance from the subject equal to the
 focal length of the umbrella-light combination. Testing your umbrella
 to make sure this is not a probrem will enable you to utillze the umbrella
 to your best advantage. The umbreila focal point is more noticeable  in
 silver umbrellas with non-textured fabrics because this type fabric pro-
 duces a harsher light. Harshness depends both on the fabric texiure
 and the reflection quality of the material. lt varies with each umbrella
 type.


                                                                                                                                                                                   Digitally signed by Mike Butkus
                                                                                                                                      DN: cn=Mike Butkus, o=Butkus camera manuals,
                                                                                                                                                      ou=butkus.org, email=mike@butkus.org, c=US                      Mike Butkus Date: 2024.05.06 22:03:51 -04'00'





                                                      Ftg. 5
                           CURYE|) R]BS CA}I CAUSE A r|lCAT POIITT

         HOW ABOUT SQUARE UMBREIIAS?
    square umbrellas produce square catch rights. some photographers
 like square catch lights because it looks like the reflection from window
 light. on the other hand, some photographers object to square catch
 lights. lt's strictly up to your personal preference.
    Square umbrellas generally have flat ribs. since the angle of re-
 flection is equal to the angle o( incidence, the light pattern produced
by a fully opened flat ribbed umbrelra has no appJrent focal point, and
thus produces a more even angle of coverage than curved ribbed
umbre llas.



                         Fig'-' o                                              Fis.7
          tuu.Y 0PEirEo uMERtttA                       CT(ISED l)()WN UMBRELI.A
        WIDER ATIGLE ()F COYERAGE                              I.ESS COVERAGE
          SOFTER tlGIIT OUTPUT                        M()RE I.IGHI OUTPUT
   Many square umbrellas can be opened to various degrees, permit-
ting the reflected angle of coverage and the  light output to be controlled
                            -4-

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at a given distance. 'tF=6iiing the'urirbr6fla Widens the angle of coverage
and lowers the light output. Closing down the umbrella narrows the
angle of coverage, increases the light output, and produces a more harsh
effect.

          WHAT ABOUT WHITE UMBRETTAS?
    White umbrellas produce a softer light than do silver umbrellas of
comparable  size.
   We have found the light loss with most white umbrellas to be ap-
proximately 2f stops less than direct light. These figures are based on
white umbrellas powered by an average studio lamphead containing an
average reflector. Our definition of an average reflector is one producing
a 10 to 1 light output ratio and having an included angle of 60o coverage.
This 10 to 1 ratio simply means that the reflector produces 3f stops more
light than the same lamphead would on bare bulb operation.
   Many white umbrellas utilize translucent fabrics. Thus some of
the light will filter through the umbrella as well as reflect from it. This
can be an advantage  if the umbrella is placed directly in front of a
bounce flat, wall or corner: the additional light reflected from the bounce
flat, wall or corner may produce an even softer lighting quality. The
translucent fabric can also be a disadvantage in situations where the
camera is located behind the umbrella: filtered light could strike the
camera lens and cause flare. With umbrella lighting it is desirable to
use a lens shade to prevent flare.


                                        -il-
                                                                                   Fig. I
                              TRANSTUCENT FABRIC
          AI,DITI(INAL LIGHT RIFTECITI)                    TII.TEREI) LIGHT MAY CAUSE FLARE.
         FROM WAI.L AIDS S()FT
             LIGHIING OUALIIY.
         HOW ABOUT SITVER UMBRETTAS?
    Silver umbrellas produce a harsher light than do white umbrellas
of comparable size. This harsh light is still much softer than the light
produced in most direct light systems. Silver umbrellas reflect more
light than white umbrellas, making them desirable where maximum
depth of field is required from a bounce light system. Our tests show

that silver umtiieltas tose from r/z to Lr/zf stops over direct light, depend-
       ing on the reflection index of the particular silver nraterial and the
       shape of the umbrella. Again, these figures are based on an average
       studio lamphead containing an average reflector.
                                                                                       a-        Some square silver umbrellas have a reversible fabric which has
t      figh contrasi design on one side and a lower contrast design on the
I      other side. This enables you to vary contrast by reversing the fabric.
I            In all the silver umbrellas tested, we found that very little light'       transmitted through the umbrella. This minimized the problem of flarewas
      due to light filtering through the umbrella. However, one must be
       aware that light traveling around the edge of the umbrella could cause
       a problem to your camera lens.

               WHICH TO USE, LARGE OR SMAtt?

          Earge umbiellab produce a softer, broader light than do smaller
       umbrellas. The larger size will illuminate the subject from greater
       angles.  lf you were to create this effect with direct light you could use
        several lampheads (fig. 10). One disadvantage of using multiple lamp-
      heads is that cross shadows will be produced. To eliminate cross
       shadows, a diffusion sheet of sufficient density would have to be placed
        in front of the lampheads (fig. 11), making them appear as one single
          light source.

         (
         (
         (

                               Fig.10                                                   Fig. 11
                  MUITIPI.E TAMPHEAI)S PRODUCE                 DITFUSION SHEEI ETIMITIAIES
                     cR0ss SHADows.                               CR()SS SHAD()WS

           Figures 12, L3, and 14 further illustrate how the size of the light
       source effects softness. In figure 12 the lamphead is pointed directly
        at the subject. The angles of reflection are great at the sides of our
        subject, thus the illuminating power of the light source is weak at the
        sides of the subject. The illuminating power of the lamphead is great
        only at the front surface of our subject where the subject plane is per-
        pendicular to the light beam.

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                                                              Front Surfrcr-




                                            lig.12
                             POWER IS WEAK AT IHE SIOES ()F T}IE SUBJECT.       OIRTCT TIGHT               -  ILLUMIIIATII{G
    Figure 13 shows the lamphead pointed into a small umbrella. The
angle of reflection is less at the sides of the trapezoidal subject than
with the direct light: thus greater illumination on the sides of our
subject is obtained than with direct light.

                                                                      Smf lr: Angfc ol Fcf letio>





                                                      Fig. 13

   SMAIL UMBRETLA: ITLUMINATES THE SIOES OF THE SUBJECT BETTER THAI{ DIRECT LIGHT.
    Figure 14 shows a lamphead pointed into a large umbrella. The
angle of reflection is even less than that obtained with the small um-
brella, thus a softer, more even light is produced.


                                                                             -     \                          ili^*di.tbri6                    //                                 \\


                                                                                    tobFr                                I





                                                      Flg. 14

     LARGE UMBRETLA: ILLUMINATES SIDES 0F SUBJECT BETTER THAN SMAtt UMBRELLA.
                             -7-

In cases where depth of field must be maintained, it takes more
light output from your electronic flash to illuminate a large umbrella
than to illuminate a small urnbrella. This is because the lamphead
must be further away from the umbrella in order to illuminate the en-
tire fabric.





           '-.._                       tig.'15                                                 tig. 18
       TIIIPHIAD BACI( FR()M UMERELIA             LAMPHTAD CI.(IS[R T() UMERTTTA
        S()FIER TIGHI, M()RE COYERAGE            IIORE LISIII INTENSITY, IESS C()VERAGT
         HOW ABOUT SMAtt UMBRETLAS?
    Small umbrellas produce a harsh light compared to large umbrellas.
      lf an umbrella is too small in relationship to the diameter of the
lamphead reflector, a good portion of the light will bounie back into
the lamphead reflector and produce a void in the beam path: you will
notice both a light output loss and a black shadow in the center of the
catch light.




                               .       Fig. 17
   UMBREILA TOO SIIATT 11{ RETATIOII T(l LAMPHEAO PRllllUCTS A VOID III TIIE ETAM PATN.
           WHERE DO YOU GO FROM HERE?
    Using these basic principles as a guide, you can more intelligently
select the best umbrellas for your particular type of photography.
   May we suggest that too much of a good thing can be bad! For
example   when using two or more umbrellas,  it is possible to makethe light -too soft or too flat. lf this happens, your photograph will lack
depth and the colors can be too bland. Don't forget that you are gen-
erally trying to make a two dimensional piece of photographic paper
look three dimensional.
                          -E-