One of the drawbacks of using direct flash is that its harsh light casts on your subject. As a small high contrast light source it produces illumination that can be very unflattering. Do you notice when popping up that on-camera small flash and take photos that faces often look gloomy and ghostly and often with red eyes? Even mildly shiny objects like wood will project that large glaring reflection in your photos.
But don't loose hope! There are many ways to combat this harsh flash problem and all solution share the same aim: to make the light softer and spread over large areas.
How to use bounce flash?
With a suitable flash unit (I personally have the Canon 430 EX II) and extremely happy with it... the easiest way would be to direct the rotating flash head to the ceiling in a way (like the pool table game) to ricochet back on your subject i.e. not flat vertical. In doing so, the ceiling surface becomes the new light source. This technique produces a dramatic effect on the quality of light you are using as well as producing a softer, more flattering illumination on faces. It also solves the red-eye problem and greatly reduces the density of background shadows.
There are few trick you need to know about however:
- You need a flash unit with a head that can tilt upward and rotate to the sides
- Your chosen surface should be white, or off-white. If it is colored, your bounced light will carry that color cast with it and hit your subject. You are most of the time lucky since most ceiling are white. And because ceilings are above the subject, the resulting illumination resembles to the light from the sky so it looks more natural. However, if you bounce it vertical at 180 degrees, it will return the light to you and your subject will be underexposed. So by all means tilt the flash around 30 to 45 degrees depending in your distance from the subject.
- Bounced light travels much farther, so your surface must be quite close to the subject. Keep in mind that no wall or ceiling reflects all the light that hits it and some of the light is scattered elsewhere. The room type also plays a role of how much light gets back to the subject. This technique won't work if you are in a wedding ballroom :(
- Like the billiard ball, flash will bounce off your surface at the same angle at which it struck the surface. If the flash bounces back above the subject's head, the result is ugly shadows under the nose, chin, and in the eye sockets.
Calculating exposure with bounce flash
Flash units are power hungry and bounce flash needs more power, so it is no surprise that the biggest problem associated with bouncing flash is underexposure. With nowadays flash units, you don't have to worry as they use a technology called Through The Lens metering or (TTL). With a TTL mode set on your flash unit, the camera knows how much of the flash has reached the sensor but sometimes (from experience) you have to keep an eye on the underexposure needle and the final photo on the LCD. With Manual flash mode, your calculation have to be based on the total distance (up + down in this case). Read the table on your flash unit manual to help you with that... Or you can try what I do: every flash unit has a sync speed (I will not go into details on this one - maybe in another post) usually between 1/200th of a second and 1/250th of a second. Start with your aperture set at 1/200 and increase if you need to or you found out that your photos are overexposed.
Flash Reflector Cards
If you don't know what is a reflector, you can refer to my post on What is a Reflector. But here we are talking about that small white card that is fitted on top of your flash unit. The concept of bouncing light is so magical that photographers have found a way to use it even if there is no nearby surface to bounce it off. Depending on the model and price, flash heads come with that reflector bounce card but don't be concerned because you can make these cards yourself, or by one you can attach to the head of any flash.
The card comes in different shapes and forms. Some come with an option to turn it into a snoot for directed light. Anyway, you can attach that modifier onto you flash head using Velcro, tape or rubber bands and the neat thing about it is that they all fit into your camera bag or jeans pocket.
The advantage of those card is that light now won't travel so far before it is bounced, but because they are small, their degree of diffusion is not great. Another advantage of those cards is that, they spill some of that fill light onto your subject, specially if they are back-lit. When using a flash reflector card, the precise position of the flash head will depend on the shape and angle of the card. It should be pointing slightly downward, but not too far - unless your intention is to light the subject's knees :)
This is something that you should be able to judge by the eye.