Shoot a Smile With Your Umbrella
Before photography was invented, painters had their studios fitted with
big north light windows because they wanted their subjects lit by a large
light source. Why? Today, every photographic catalog has a lighting section
filled with big umbrellas and bank lights, both of which represent large
light sources.
In fact, big light sources are so common today that almost
everyone’s mental image of a fashion photographer includes lights
flashing into big umbrellas; just look at any TV show or movie that features
a fashion photographer taking pictures to prove my point.
The stereotype
is so ingrained in our society’s concept of photographic lighting
that even Felix Unger used them! Why? Because big light sources, often
called “broad light sources” (be they a north light window,
an umbrella light, a bank light, or even a flash bounced off the ceiling
or a wall), create beautiful light and flatter the subjects they illuminate.
You too can use a broad light source to both impress your photographic
friends and get rave reviews from your subjects! Understanding why this
is true and putting that knowledge to work can make your pictures better.
Gift Wrap? Soft Light?
Experienced photographers will tell you that big light sources “wrap
around” the subject they are aimed at, or that they put out “soft
light”. But, can you really use a big light to cover and decorate
a holiday gift? Is the light from a broad source really soft like a cotton
ball or a marshmallow? Of course not!
Because light rays only travel in
straight lines they can’t really wrap around anything, and soft
lights are neither cotton balls nor marshmallows--but there is some truth
in these claims.
What these photographers are trying to put into words is how a big (or
broad) light source differs from a little (or point) light source. That difference is best exemplified in the shadows they create. Now look
at sketches #1 and #2. They trace light rays coming from the far edges
of both a broad source (a 55-inch umbrella is depicted in sketch #1) and a point source
(a typical 2x3-inch flash is shown in sketch #2) with both illuminating a 12-inch
human head from the side. Importantly, both light sources are five feet from
the subject (but in the umbrella sketch, #1, the distance is measured
from the center of the umbrella’s surface and not from the light
source) and the two sketches are drawn to the same scale.
In both instances
I used a red pencil to fill in the shadows created by the subject from
each light source. Notice that the size of the broad source lets its edge
rays (which are always straight) reach further around the subject so,
in a way, the broad source does “wrap around” the subject
but it’s not because the light rays bend or curve.
Umbra and Penumbra
Not only does a broad light source make smaller shadows than a point source
light, but also the edge of the shadow’s pattern is more graduated
than the edge of the shadows from the point source. This edge of the broad
source’s shadow pattern is often termed “softer” (than
that of a point source) and that is why broad light sources are sometimes
called “soft lights”.
A shadow is made up of two parts called
the umbra and the penumbra. While the umbra part of a shadow is the total
absence of light, the penumbra is a lighter part of a shadow that is partially
illuminated. Point source lights have a very small penumbra (basically
irrelevant in real world situations) but broad light sources have a much
larger penumbra.
It is this larger penumbra that makes the shadow’s
edge more gradual (softer) and this is what helps minimize the subject’s
flaws. Look at sketch #3 to see where the penumbra is. Sketch #3 is the
same as sketch #1, but this time I have defined the penumbra and shaded
it in turquoise while leaving the umbra shaded in red.
So What?
To illustrate just what this means in a real world situation I cut the
eraser off a pencil and glued it to a white card. I then took a picture
of the eraser with the 55-inch umbrella light and the 2x3-inch point source
light using the same dimensions (only full sized) that I used in the sketches.
Bearing with me for a moment, lets make believe the eraser is a huge pimple
on your subject’s forehead!
Accepting the fact that this would be
a very big pimple in real life, notice how the broad source light minimizes
it and the point source light accentuates it. Interestingly though, note
that it’s the shadow each light source creates that calls more or
less attention to the pimple… I mean …eraser. Now, scroll up and take a
look at sketches 1 and 2 to better understand this effect.
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A broad source shadow…
note the penumbra! |
A point source shadow. |
Natural Broad Sources
Even if you don’t work with photographic lights or flash units and
prefer available light, understanding these concepts can improve your
photos. Remember that the sun (definitely an available light!) is a point
source while the sky is a broad source. That’s one reason why so
many pros (including myself) look for open shade when shooting outdoor
portraits.
The sun offers better, more natural, color than the bluish
sky, but by adding a warming filter over your lens (such as an 81A or
81B or adjusting the white balance on your digital camera) you can take
care of those open sky blues. By placing your subject in the shade you’ll
end up with photographs that both you and your subject will enjoy more.
Another example of a naturally occurring broad source is the sky on a
cloudy day when the sun casts no distinct shadows. Like open shade, cloudy
days are also bluish in color but the warming filter(s) mentioned above
can take care of this in a jiffy. In fact, if you use a warming filter
and are careful not to include the sky in your background this type of
light is amongst the most flattering for people pictures.
Indoors there is window light, and when the sun isn’t shining directly
through the window, it is a pleasing broad source that can be found almost
everywhere! As a hint here, remember that windows with a northerly exposure
never have sun shining directly into them and sometimes, subjects lit
by a north light window can benefit from an 81A or 81B filter also.
Once
you know that there is no direct sunlight (a point source) shining into
north light windows you’ve discovered the reason why painters almost
always had north light windows built into their studios! Some of you will
remember that this thought was mentioned at the very beginning of this
column so we have now come full circle and it’s time for you to
buy, create, or find a broad source of your own and start making beautiful
people pictures!
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