1-When would you use external flash?
To either catch a fast-moving subject or of something with poor lighting.
2-Do you need to meter the light if you use flash?
No, you do not need to meter the light if you use the flash because you do not work with natural lights.
3-What does flash synchronization mean?
Flash synchronization is when the fastest shutter speed in which your camera can successfully process the flash.
4-What does ETTL mean?
ETTL means Evaluative through the lens, which is a type of auto flash exposure system used by Canon.
5-What will happen when you shoot faster than the camera sync speed?
The image will be half dark and the other half will visible.
6-Why do photographers bounce the flash and use a diffuser?
Photographers bounce the flash and use a diffuser to soften the light, which makes the image stand out more.
7– What is a slave?
A slave is a feature that can trigger multiple flashes at once in an instant.
8-What should you do if your image comes out too dark or too light?
Adject the aperture. When your image comes out too dark, you lower the aperture number. When your image comes out too bright, higher the aperture number.