External Flashes can be one of the more intimidating aspects of photography, but an external flash can be a great addition to your photographic arsenal to really take your work to the next level.
It’s not just for letting you shoot at night, even in the middle of the day when you think you have plenty of light the addition of a little extra light can really your subject pop.
Generally speaking the bigger the light source the better the picture will be, a tiny flash on your phone isn't going to work as well as a big external flash, and that isn't as good as a large umbrella. If you don’t have a umbrella just twist the flash head to bounce the light off the wall or ceiling, or someone’s white shirt, alot of them even have a little white card you can pull out to bounce a fraction of the light towards the subject. When you bounce the thing your bouncing off of becomes your light source so that tiny bulb become a massive wall of light.
Another Objective is to get the flash as far away fro the lens as possible, that's why most flashes pop-up from the camera... the designer is trying to get the light source further from the lens (this also has the added bonus of reducing the chance of getting red eye). that's also why photographers love long cords or radio triggers … it also unchains us from the location of the light on our camera and gives us the creative freedom to move around and get the shot in our heads.
Tricks to remember:
your camera’s shutter speed will affect the background only, my formula is to use av mode to figure out the “ideal” speed/aperture, move the camera to manual mode and set it to that, cut on the flash then play with the speed to get the background I want, then raise or lower the flash power to get the subject how I want them.
Know your limits
cameras have a maximum sync speed this is the fastest you can go in shutter speed when using a flash, it has to do with the limitations of the physical parts of the camera. Alot of lenses have a feature you can enable called high speed sync - this allows you to ignore this limitation: instead of 1 burst the flash pulses, it takes more power and and lose a little light but it’s extremely useful.
You also have a maximum distance - light drops off quickly (we call this the inverse square law) - for every step you travel away you lose the lion share of your light’s power (if at 1 ft your at 100% then when you double the distance to 2ft you’ll be at 25% of your power, then another foot you’ll be down to 11%, then 6% … so at 4x your distance you’ve lost 94% of your light’s power) Important to know in if your flash is in manual mode, it ETTL it’s going to automatically adjust to put out more light as your subject gets further away, but be aware that your battery is getting drained as it does so.
So in summary if you want to improve your shots:
1) get a external flash and try shooting with it
2) get it off your camera if you can
3) big close light is better - think umbrellas or bouncing off walls (maybe add a reflector too)