So, what are the options in continuous lighting? Our popular choices today come down to hot lights (photoflood and halogen) and cool lights (fluorescent and LED). High-intensity discharge lighting, popularly known as HMI, is a bit specialized for the purposes of this article, so we’ve left them out this time, but as that technology becomes more accessible for DP readers, we’ll be adding them into this mix as well.
The uppermost concerns with any lighting solution are light quality (hardness or softness); beam spread (narrow or wide or somewhere in between) and color (to avoid introducing intrusive color casts). Depending on your needs, the quantity of light may also be a factor, regardless of ISO. Equally important are cost (to buy and run the lights) and environmental concerns (at least for some of us).
Photofloods and halogen lamps (3400K and 3200K, respectively) comprise this group. Hot lights are so called for a reason. In wattages normally used in a continuous-lighting studio, 250W and more per fixture, these incandescent light fixtures not only are hot to the touch but also generate an uncomfortable amount of heat forward toward the subject. More lights and/or higher wattages add to the level of discomfort.
The fixtures for these lamps accept a wide range of optional accessories for shaping and modifying the light. However, be selective with softboxes for bulbs brighter than 250W, as they must be heat-resistant and vented to circulate air and tolerate the heat buildup so as to prevent potentially hazardous conditions. The more expensive halogen fixtures may be focusable for broader or tighter coverage. Halogen has long been popular for run-and-gun (on-camera) video recording.
Photofloods. These are economical, in terms of initial cost and bulb replacement, however, they have a relatively short life and aren’t particularly energy efficient. Photofloods are a good choice for entry-level studios. If you’re photographing adults and older children, they can work well, but don’t use photofloods for babies or toddlers. They’re also good for still lifes.
Halogens. This is the industry-standard form of continuous lighting. They’re much more efficient, but also more costly than photofloods. They’re reliable and last several hundred hours, give you good "light throw" and are available in high wattages of 500W and more. On the downside, halogens aren’t as energy efficient as fluorescent or LED, and their glass envelopes may weaken and shatter over time if handled with bare hands—never handle a halogen bulb with a bare hand. Halogens are good in the studio and on location. You can photograph adults and children with them, but it’s best not to use halogen lights when photographing babies. They’re excellent for still life, food photography and architectural interiors, where they’ll also mix well with existing incandescent lighting.