Portraiture doesn't require complicated, multi-light setups to pull off beautiful and striking images. Here are four one-light setups you can learn in ten minutes.
A lot of great portraits are made using three lights or more, and that can be offputting to newcomers to the craft. It's in this area that some misunderstandings are often had over what having more than one light provides a photographer. Having only one light doesn't mean you can't create beautiful, professional portraits, it just means you don't have access to some lighting setups. If you had a studio with 20 Profoto lights, there would still be instances where you use just one.
For more complicated lighting setups with only one light, you'll likely have to be creative with reflectors, mirrors, or natural light, and it may not be quite as good as if you had extra lights, but it's certainly possible to pull off still. Where possible, however, I would gravitate towards mastering single light setups. For example, many low-key portraits will only use one light. So, if you only have one available to you, perhaps practice low-key, moody portraits.
In this video, John Gress goes through four possible setups using just one light, some common mistakes when setting them up, and the justification behind elements of positioning the light.