If you've ever had to take a portrait of somebody in glasses, you'll likely know that it can be a tricky process. With the eyes tending to be the focal point of a portrait, glare on their glasses can ruin everything, and so you need to know how to handle it.
The first time I ever realized that glasses can be an issue in portrait photography was when I bought my first strobe light and softbox, and decided I want to practice with some self-portraits. From there, I sat in that room in my house and I tried every different angle and filter. I learned more in that brief period of experimentation than I had in many full tutorials. In fact, what I learned became crucial to my career later on.
I have written about one of my biggest regular clients before. They have hundreds of employees and I take each of their headshots, as well as multiple shots of each working. So, I end up taking thousands of pictures of people, many of which have glasses. You seldom get long with each subject, and getting the lighting right has to be a fine art. That becomes more difficult, however, when the person has glasses of varying sizes and thicknesses.
This video is a great introduction to the problem and offers some potential solutions. I would implore any budding portrait, wedding, or event photographers to put the time into learning how to deal with glare — it will pay dividends!