When would you use external flash? You use this when its dark or the lightning is too low. Do you need to meter the light if you use flash? Yes, you do. What does flash synchronization mean? It matches the flash firing with the shutter opening in camera. What does ETTL mean? Evaluative through the lens. What will happen when you shoot faster than the camera sync speed? The image will come out dark and will have uneven exposure. Why do photographers bounce the flash and use a diffuser? so it can soften the light. What is a slave? A slave is something that you connect to the camera for the flash. What should you do if your image comes out too dark or too light? you should check your iso and if its high lower it or use a faster shutter speed.