Catchlights are those highlights that give life to your subjects' eyes in your photographs. Without a catchlight, the eyes can look lifeless. So much so, that in the old days of glamor and hollywood portraits they would paint in catch lights if the lighting setup didn't provide them.
Every once in a while I get into a discussion with other photographers about catch lights. Some people like round ones. Others like rectangular. I fall into the "rectangle" camp and would like to offer my reasons. I also like LARGE round catchlights, such as from a large octabank. See my next post for more about that.
When I think of catchlights, I think of old masters paintings. And I think of light coming from a window or a doorway. And in most situations, those windows and doorways are rectangular. But what about the great outdoors? The catchlight in the great outdoors is often provided by the full sky. And that tends to be rectangular in shape.
Other folks say that the catchlight should be round. They say the main source of light in the world is the sun, and the sun is round. I don't disagree, the sun is pretty much round. But the sun rarely provides a catch light. For one thing, it is so far away that if it does show in the eye, it is just a pin-point. And if the sun is shining directly into the subject's eyes, their probably squinting and not looking all that comfortable, and the squint may be blocking the catchlight. Or it is so bright that the subject looks away from the sun, and now the wide open sky provides the light for the scene and the catchlight.
So, there's my argument. But, as with all things, it doesn't matter what I think. It doesn't matter what other photographers think, either. It just matters what you think. You like round catchlights? Use round lights or modifiers and be happy. You like rectangles? Use rectangular lights or modifiers and be happy.
All I ask is that you think about it and reason out why you have one preference over another. And maybe you don't have a preference. That's OK, too.
And now you get to look at my pretty face (that's what happens when the model has to cancel at the last minute)...
This first image was created with a Photoflex Silverdome NXT Medium Softbox. Below is a close up crop of my eye from the above photo.
This second photo was taken using a Speedotron 22" beauty dish with a diffuser on it. Below is the close up crop.
This third image goes back to the Photoflex softbox, but I added three strips of black tape across the face of the softbox to try to imitate the look of a window. Again, below is the close up crop.
What is your preference for the shape of a catchlight? And what do you think of multiple catch lights, as you might get from some multiple light studio setups? The above photos were all made with one light and no fill, so only show the single catchlight in each eye. A reflector board or secondary fill light may have added an additional reflection in the eye.
For this image, I kept with the Photoflex softbox, but added both a white card and a Photoflex 32" 5-in-1 MultiDisk reflector with the gold covering, which provided an extra reflection in the eyes (as well as a warmer overall tone to the image). In this case, I don't think it detracted. But if the extra reflections were harder and more similar to the main catchlight I would suggest removing the extra catchlights in retouching.
Speaking about catchlights and portrait lighting, the catchlight is what we call a specular reflection. It reflects the light back to the camera like a mirror. And like a mirror, the brightness will remain the same, no matter the distance between the light and the subject. At first, this seems to contradict the inverse square law, but it actually doesn't. The inverse square law says that when you change the distance between the light and subject, the amount of light will change by the square of the change. So, if you moved your light from 2' to 4' from the subject (2x the original distance), the subject would receive 1/4 the amount of light. If you moved the light 3x the distance, the subject would receive 1/9 the amount of light.
In the case of a mirror reflection, instead of the brightness changing, the size of the light will change. So if you move the light twice as far back, instead of the light falling off to 1/4 power, the size of the light in the eye would be 1/4 the size, but at the same brightness. Knowing this, we can control the brightness of the catch light. To make it darker in the overall exposure, you would have to bring the light in CLOSER. By bringing it closer, the catchlight gets bigger, but remains the same brightness. However, by bringing the light in closer the overall scene (the face) gets brighter. And you have to lower the exposure (stop down the lens or lower the power of the strobe) to get the proper overall exposure, and by doing so, you are also darkening the specular reflection, bringing closer to the overall exposure level.
Remember to check my follow up post about larger catchlights.
All images taken with a Canon 5DmkII and Canon 70-200L f/4 IS lens. Manual white balance setting of 5700 degrees Kelvin was set in the camera. Light was a Speedotron Force 5 monolight that remained the same spot for all images (just the modifier was changed between the softbox and the beauty dish. With a little bit of work the Speedotron beauty dish can be modified to fit onto other strobes, but you are on your own for that. At around $150, this beauty dish is a bargain.