Selecting the Right Size of Main Light Source

All too often speakers, educators and lighting companies talk about the size of main light modifiers as though one size (which is typically the largest and most expensive they offer) will work for every application/style of portrait.  Each light modifier produces light with a certain characteristic.  While each light modifier has a slightly different characteristic, it really is only slight and not always worth investing in for the small differences you will see in the final portrait (when comparing one brand or shape of light box to another).

What does affect lighting the most is the size of the light box you are using in relationship to the distance from the subject you are photographing.  While everyone talks about using a six-foot light box (I use one on occasion myself) a six-foot light box is often too large for most portraiture that is taken from the waist up.  A six-foot light box is great for shooting full lengths or groups of people in the studio, because the relative size is smaller since the main light has to be positioned farther from the subject.

The problem with a larger light source for a single subject is it gives you little control over where the light is striking the subject and in today’s over-weight world, you find that shadow helps sell more portraits than light, because people have fewer areas of their body that are comfortable showing in the final portrait.  For younger photographers, it is important to understand the relationship between the size of the light box and the distance the light box will be placed from the subject/subjects.  While a six-foot light box is ideal for full length portraits or groups a much small light box should be used to achieve a consistent light characteristic.  That sounds complex, but really it is simple, for the same look in all of our portraits (from head shots to full length) I use different sizes of modifiers based on how far from the subject they will be placed.  I will use a small box for tight head shots (or corrective lighting) a medium box for waist up to 3/4ers and a very large box for lighting full lengths using a set or larger scene.  This way our lighting has a very consistent look as they view similar styles of portraits that very in composition from head shots to full lengths.

As always, I will explain further for the few photographers that like to argue and point out the obvious.  Here we go for Captain Obvious, yes there are times that you select the same modifier for different looks to your lighting.  In any given session, I will use everything from a soft box, to a spot light, a parabolic with barns doors to Butterfly lighting and even a fashion ring light, but the first step is to be able to understand the basic portrait lighting and master it, before working with other styles of lighting.  To master portrait lighting, you should be able to produce the same “light quality/characteristics” on every portrait from a head shot to full length.  This is accomplished by selecting the correct size of light box for the job at hand.


~ by jeffsmithbooks on June 28, 2011.

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