One Light: Group Shot

by Stanley LearyGroup photos / studio strobes
Reading Time: 4 minutes
Students helped me demonstrate the issues of a problem with one light close to the group. The person closest is brighter than the others.
Here, all I have done is repositioned everyone, but the lady on the far left is still darker than the other two in the photo.
This is the lighting setup for the two photos above.

After seeing the photos above, one of the first things people think they need to do is add another light. No question this would help solve our lighting problem.

Now let’s be realistic here. Most photographers starting will have just one light and cannot justify another until they begin earning income. How do you solve the problem in just one morning?

Inverse-Square Law

We need to first start with understanding the Inverse-Square Law of Light.

In physics, an inverse-square law is any physical law stating that a specified physical quantity or strength is inversely proportional to the square of the distance from the source of that physical quantity. (Wikipedia)

In photography, an object twice the distance from a point source of light will receive a quarter of the illumination.

How this is most often used in photography is to determine your exposure. If you want to keep the same f/stop when you move a light twice the distance from the subject, you must increase the power four times. Inversely, if you move the lamp twice as close, you will need to power down the light to 1/4 the power to keep the same f/stop.

Using the Inverse-Square Law of light for a group photo

The further you move the light from a group, the less the light falling on the subjects’ faces will differ. The reason is that the distance of each subject to the light source, as compared to others in the group, will be so small a difference that they will appear to be more evenly lighted.



The only thing that changes from the first diagram to this one is that the light source is moved farther from the group and to the left.

As shown in the lighting diagram, I have moved the light source further from the group. I suggest moving the light as far away from the group as possible to get the most even light.

You can now see that the light is more even on everyone in the photo. One person said it is light, creating a depth-of-field effect with the flash.
While this would have solved the lighting problem by keeping the lighting the same as in the first photo, it would limit your creativity when posing with a single light. This is why moving the light back gives you more posing options and more light in a group photo.

Technical Changes

  • ISO: You may need to use a higher ISO to keep your flash effective. You may change from ISO 100 to ISO 3200. Remember that, since you are using a flash, the noise is different and can actually seem to disappear. (link to earlier blog on this)
    • Aperture: For group photos, use f/8 or higher to ensure everyone is in focus. If you use f/2, for example, your group photo above would look more like a solo act with backup singers than a musical group.
    • Studio Strobe vs Hot Shoe Flash: This is when it makes more sense to own a studio flash than a hot shoe flash. You can get more power, and the recycling time is much quicker. (Earlier Blog Post comparing hot shoe flash and studio light)

You can buy hot shoe flashes for under $90. These hot shoe flashes are not TTL, but you can use them in manual mode just as you would a studio strobe. They are just less powerful and take a while to recycle.

This is the Vivitar 285, which you get at B&H Photo for $87

Practice making a group photo and evenly lighting everyone with just one flash. Understanding and mastering this skill will help you when you have limited equipment and still need a professional group photo.