Light modifiers

As per title, this post is all about light modifiers, and light modifiers only. I’ve had the luck to attend a couple of friends weddings this passed couple of weeks. The events were great. What struck me however was the choice of the light modifiers for the on-location event coverage.

Let me start by stating that I am no light guru by any means. I’m still exploring light and its application but as most of you, I also apply common logic when it comes down to using it. That being said, let’s move to the topic of light modifiers. Light modifiers, when dealing with strobes – studio, portable or otherwise – are exactly that; tools that allow photographers to modify light; that being, modifying the (apparent) size, intensity, colour and direction of light. Mind you however that despite their commonalities (they all are hit by light in a way or another) each mod serves a different purpose. Let’s start with the first use of light modifiers as listed in the previous sentence. The apparent light size. The majority of photographers dealing with light are familiar with the concept of apparent light size and its importance when illuminating an object and creating light and dark zones. Put in simple terms, the bigger the light source relative to the object we are trying to illuminate, the softer (if any) the shadows created. First of lets explain the way it behaves when hitting an object of interest. When observing the object, we immediately identify at least two zones, the illuminated  zone and the shadow zone. The illuminated zone, as its name implies, is the zone that receives light and reflects it back. The shadow zone is the complete opposite; it’s the zone that receives no light and stays in the dark. There exist another two zones however that most non-photographers don’t care about, so most of the times they go unnoticed. One of them is the transitional, light to dark zone. The other one is irrelevant for now. The transitional zone is the one that receives part of the light but not all of it. The length of this zone – from full bright to complete dark – is what defines how hard or soft the shadows are. Again, simply put, if light moves rapidly, from the full brightness of the illuminated zone to the darkness of the shadow zone, it creates hard (or harsh) shadows. If the transition is more gradual, it creates softer shadows. This transition is affected by the apparent light source size. The bigger the light source compared to the object of interest the softer the shadows; the light effectively, wraps more evenly around our object. The intensity of the light falls with distance hence the areas further away from the light source are illuminated less. This creates a bigger transition zone where intensity is spread evenly creating softer shadows.

One way to use light modifiers is to increase the apparent light size. Position your strobe 2 meters away from an object, shoot and observe the shadows. Now attach a medium softbox to the strobe without altering the distance to the object and shoot again. The shadows of the second setup are much softer. Why? Because the size of the strobe has increased relative to our object. To soften the shadows even more, remove the softbox and bounce the flash from a white ceiling. Now the ceiling acts as a huge light source relative to our object, softening the shadows even more.

By now you should understand the relation of apparent light size and shadows. To wrap up, the bigger the light source, the softer the shadows.

Off to the ranting criticizing part of this topic. In both weddings I attended, the photographers used the built-in bounce card of their speedlights throughout the whole day; for the ceremony at home, to the church ceremony, to the dinner afterwards. Bounce cards are a type of light modifiers with purpose to redirect the light. They are used in addition to the bouncing action of the speedlights to eliminate “racoon eyes”. “Racoon eyes” is the effect created when light comes from above. Because foreheads protrude, they tend to create shadows in the eyes when light comes from above. This is where bounce cards come in handy. They redirect some of the light forward and directly towards the object hence illuminating the eyes and avoiding the “racoon eyes” effect. By applying some common sense, you can easily identify that you get no practical benefits by having the bounce card on, if the ceiling is high above or if shooting vertically, and the bouncing surface is very dark, hence no bounce. This is the case with churches. The ceiling is too high, often over 25 meters high and the direct distance of camera and speedlight to bride/groom is only a few meters. This means that the bounce has no effect. Same thing if the flash is bouncing off the dark wooden chairs if shooting vertically and the flash is pointed towards the chairs. There simply isn’t any bounce. Light does not bounce off dark surfaces. Using bounce cards, only drains the speedlights batteries while retaining the harsh shadows. After all, the bounce card is considered a small light source, sometimes even smaller than the flash head itself. To best use this type of light modifiers, make sure you have a low enough ceiling to use as bounce source. If the ceiling, or bounce surface is high, you are much better off shooting directly and letting your in-camera TTL meter and computer combo do its magic. Make sure you know how to expose for the ambient light and the proper illumination will be decided upon by the camera given that you know how to effectively work with TTL