Pedrosa: Artificial Light Part II

Albert Pedrosa
Photo mania

IN MY previous column, I mentioned both continuous and strobe lights as types of artificial lights. One of the major differences between the two types of light is that continuous light can be controlled by your shutter speed while strobes are limited to the camera’s flash sync speed. It means that you cannot shoot at high shutter speeds when using strobes, unless you’re shooting in high speed sync mode. This is only possible when using a proprietary portable flash.

The flash sync speed is the maximum shutter speed that the camera can expose an entire focal plane or sensor with the shutter curtain fully open. The characteristic of shutter curtains at higher speeds is to start closing even if they haven’t fully opened yet. A typical DSLR has a flash sync of 1/200 while a Hasselblad is at 1/800.

Therefore, when shooting in the studio using strobes, you can only control the exposure through your aperture and ISO (film speed). The rest of the controls will come from the variable power of your strobe. Losing one control such as the shutter speed is not much of a problem when shooting strobes, since the lighting is controlled.

Another interesting part of artificial lighting is modifiers. These are studio light accessories to control the quality, color, direction and mood of the light. A softbox is one of the most popular modifiers to soften the light. It bounces the light inside the box to mimic a bigger light source and filters the light through its diffuser. An umbrella light modifier is another light source normally used to soften the light. The rule of thumb is the bigger the light source the softer the light.

The signature of a softlight is a soft shadow edge. Skin pores normally create a small shadow within the pores. If softlight is used, these shadows would not stand out and exaggerate the pores, thereby getting a softer skin. A hard light on the other hand creates a strong hard shadow edge and strong highlights. A hardlight can be created using a standard light reflector and are normally used for backlight or rim light.

The direction of the light can also be controlled by a number of light modifiers. A honeycomb modifier narrows the light while a barn door controls the angle of light from four different sides. The purpose of directing the light is to limit light spilling to other parts of the scene. Light spills can cause over exposure when you add them up, coming from different strobes in the set.

I’ll tackle more about artificial light in my third and last installment in the next article. Meanwhile, photographers here in Cebu were graced with good weather during the Fifth Scott Kelby Worldwide Photowalk last Saturday, Oct. 13, 2012. There were about 32,000 walkers from all over the world, and it was indeed a very successful event. For those who want to join the photo contest, the deadline for submission of entries is Monday, Oct. 22. Keep on shooting, everyone!
photography@grp.ph / www.grp.ph