Posts Tagged ‘food’

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Tungsten vs. Fluorescent vs. LED lights: Efficiency & Heat Generation (Post #2 of 4)

Wednesday, February 27th, 2013

This post is the second in what is going to be a short series comparing different types of continuous lights for photo and video use. In the previous post I talked about how in deciding which type of lights to buy in my next round of equipment purchases, there were a lot of considerations. In this post I’ll talk about two of them specifically: efficiency and heat generation (this post will make more sense if you read the first one). Links to the other posts in the series are at the bottom of this post.

Efficiency (i.e., power usage)

Tungsten lights use a ton of power. A huge advantage of HMI, fluorescent and LED lights is that they use a small fraction of the amount of power that tungsten lights need to create the same amount of light. For example, two of these common 45-watt fluorescent bulbs (for a total of 90 watts) are brighter (5600 lumens) than a standard 300-watt tungsten fixture such as this Arri 300 fresnel (5200 lumens). That’s almost four times the amount of light created per watt of power used! For many people, especially studio shooters, this may not be important. For me though, it is. Nearly all of my work is done on location, and sometimes even outdoors, so wall power outlets are sometimes hard to come by. HMI, fluorescent and LED lights use so little power that it is actually feasible to power them by battery (for example, the 1×1 LED panel I just bought has a V-mount battery plate on the back), which is great if access to wall power is difficult, and is pretty much out of the question for tungsten lights. Advantage, HMI, fluorescent and LED.

Being able to power an LED panel off of this is really handy.

Being able to power an LED panel off of this is really handy.

Perhaps even more importantly though, the lights’ efficiency is what dictates their…

Heat Generation (aka, “Will these lights make my subjects sweat and burn me if I touch them?”)

As anyone who’s ever made the mistake of touching a tungsten or HMI light after it’s been on for a while can say, these lights generate heat. A lot of heat. Instant-blistering-burn heat. Additionally, not only do the heads themselves get hot, they also radiate heat toward the subject. So this is a doubly-important issue: not only are “hot lights” inconvenient to work with because you can’t touch them with bare hands (instead you need to use gloves, pliers or another tool when changing scrims, for example), but they also deliver a lot of heat to your subject, which is bad for a whole slew of reasons for a whole variety of subjects: if you’re shooting a fragile object like food or flowers, the heat can wilt, melt or otherwise harm the object. If your subject is a person, the heat can make the person uncomfortable which can lead to a less-than-ideal interview, or cause them to start sweating.

Try this with a tungsten or HMI bulb and you'll end up in the emergency room!

Try this with a tungsten or HMI bulb and you'll end up in the emergency room!

Tungsten and HMI lights get very hot, but fluorescent and LED lights don’t. Both fluorescent and LED lights will get warm to the touch, but will never get so hot that they’ll burn you if you touch them (or, at least, they shouldn’t… if they do, something’s wrong) and they don’t radiate almost any heat to the subject. I don’t shoot a lot of food or flowers, but I do shoot people, and I want my subjects to be as comfortable as possible, so this is a big deal to me. Once again, advantage, fluorescent & LED.

Tomorrow I’ll talk about the portability and speed of setup and ease of use of each of these lights.

(Update: links to the subsequent posts in this series are here:
Post #3: Portability and Speed of Setup & Ease of Use

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