How Many Watts Do You Need for Studio Lighting?

Gone are the days when commercial photographers relied upon natural sunlight to illuminate their subject. Today’s studios rely upon artificial lighting setups to create the desired effect. When choosing lights for your photographic studio, how many watts or watts per second is one component that affects the quality of your shot and the cost of your lighting units.

You need around 200-300 watts for studio lighting for a small commercial photographic shoot. For larger studios and more subjects, strobes around 400-500 watts will do the job. However, the number of watts you require varies according to what you shoot and the setting. 

This article looks at how watts shape your photography. You’ll also discover how to make the most of your lighting kit by getting your camera settings in line with your strobe. Read on to learn the fundamental principles of optimizing lighting for your shoot.

Should You Opt for Maximum Wattage?

Photographers and lighting manufacturers use watt-seconds to describe a light’s power output within one second. Joules is another way to refer to this measurement. The higher the number of watt-seconds, or watts, the more powerful and more power-hungry your bulb. Often, the greater the wattage, the more expensive the cost of the kit, too. 

So, should you opt for maximum wattage? In the same way that many photographers will not shoot in the intense midday sun, a light that’s too powerful will create high contrast images and burn out detail. Choosing the right wattage then aligning your aperture accordingly is key to an effective lighting setup. Also, ensure you can dial down your light to use less power in certain scenarios.

It also pays to remember not to depend upon the accuracy of the energy rating of your flash, as there are factors that impact how energy is converted into lighting power. Reflectors, diffusers, and filters alter the usable light. They diffuse, reduce, or intensify it, so wattage is only one component in your studio lighting. 

Factors to Consider When Selecting Your Bulb’s Wattage

Here are other significant factors to consider when selecting your bulb’s wattage. After, we’ll look at what this means for your camera settings:

The Subject You Are Shooting

If you are doing a newborn shoot in a warm compact studio with good natural light and your subject’s movement is limited, an 800-watts strobe will be too much. Even when you dial its power down to 400-watts, you’ll have too much lighting power flooding through your aperture, so you’ll have to dial down your aperture, affecting your depth of field.

Conversely, shooting in wide open, dark cavernous spaces with a bulb that’s lacking in power will leave you compensating for the lack of light. The number of watts you need also varies according to the number and size of subjects within your shot. 

As a hobbyist portrait photographer, you’ll do well with 300-watts for a two-person portrait shoot, but for group shots of 6 or more, crank up your watts. Watch out for our guide to watts later on.

The Bulbs That Are Lighting Your Shot

Lumens is a means for measuring the visible light output from a source. Lumens has replaced watts when talking about specific bulbs and their light output. Most lumens describe light from continuous light sources, which are frequently LED bulbs (such as the TORCHSTAR A21 LED Bulb), not Tungsten photographic globe bulbs (such as the SYLVANIA 11560 ECT Photography Lighting).

As a rough guide, tungsten lights produce between 12-18 lumens per watt. In contrast, LED lights push out a whopping 30-90 lumens per watt. This difference nullifies any conversation about wattage concerning light output but matters when you’re talking about not overloading your power source. 

CRI, Light Temperature, and White Balance

Photographers have a variety of lights to select from, including the types of bulbs. From Tungsten incandescent for ultimate brightness through strobe lights, monolights, or continuous LED panels, each type brings subtle challenges to capturing accurate color. There are other crucial aspects of lighting for cameras.

Color Rendering Index

It’s not only the wattage you need to consider but also the color accent that a bulb lends to its subject. Nobody wants a green-ish tinge distorting their portrait’s skin tones, so be sure to check the CRI or Color Rendering Index of your lighting choice. 

Your lights need to reveal the colors of whatever you’re shooting accurately, but not every light reveals the true color of what it shines upon. Add a camera lens and sensor to the equation, and colors get distorted. To overcome this matter, select a lighting kit that has bulbs with a high CRI rating. The higher the CRI number, the more accurately your camera will read the colors.

Color Temperature and White Balance

We need to address the technical aspect of managing color temperature. If you struggle to shoot colors accurately, it isn’t a matter of having the wrong lights; it’s a matter of needing to set your white balance to the artificial lights you’re using.

Check the white balance and temperature of your bulb and set your camera’s WB to fit. Once the white balance is attuned to the lights you’re shooting with, you’ll receive a neutral tone to your images, and colors will be accurate, rather than too hot or too cold.

For more information, check out my other articles:

• Make Your Studio Lights Look Natural

Rough Guide to Watts for Your Subject and Location

Here is a rough guide to selecting the wattage in relation to your subjects and their location. Later, we’ll explain how to tally your F-stop to your strobe setting. 

Watts	Subject or location
300	Great for home studio set-ups and hobbyists Pictures of kids and newborns Small product photography shoots Group portraits of only 2
400	Perfect for home studio Portraits Larger product  photography Portrait sessions with groups up to 6
600	Professional photographic studio For products such as vehicles Outdoor shoots Groups of up to 20 people
800	Professional lighting set-up Full-size photographic studio On location sets Upwards of 20 people Large subjects

If you’re debating what power strobe to invest in, a 400-watt strobe with dial-down ability is a great option that’ll cover most situations. The Godox AD400 Pro is a cost-effective monolight option that produces pure light, is portable, and includes a modeling light.

Getting Your Strobe Lights and F-Stops Right

When shooting in an artificial light situation, you must pair your camera to the light quality, which means adjusting your F-stop to be compatible with the strobe’s power output. 

A strobe’s power increments run from 1.0 to 6.0, which represents six stops. 1/1 is full power down to 1/32, at the lowest power or wattage output. These settings are not in sync with your camera’s F-stop range, so you will need to experiment with your lights and camera in situ to find the perfect F-stop. 

Also, for every diffuser or modifier that you add to your lighting setup, the power of the light will alter. This means you must compensate by adjusting your aperture setting. A light meter will help you gauge the light power and deduce the best F-stop. 

Final Thoughts

Watt seconds correspond to the power of the light that lands upon your subject, and you need to use the most powerful light available. Instead, consider what you’re shooting and the effect you want to create. 

Then, take the time to set your camera, so it’s attuned to the light your studio lights cast. Once familiar with your lighting kit and lighting for the camera, you will advance your photographic ambitions and range.

Sources

• Digital Photography School: An Introduction to Buying Studio Flash Lights 
• Google Books: The Concise Focal Encyclopedia of Photography
• Film Daft: How Many Watts Do I Need for Video Lighting?
• Food Photography Blog: Four Types of Artificial Light for Photography & What You Need To Know About Them 
• Wikipedia: Color Rendering Index