1-When would you use external flash?

When you want to get better lighting outside.

2-Do you need to meter the light if you use flash?

Yes

3-What does flash synchronization mean?

The process of coordinating the firing of a flash with an open shutter.

4-What does ETTL mean?

Evaluative Through The Lens.

5-What will happen when you shoot faster than the camera sync speed?

It causes bending and uneven exposure.

6-Why do photographers bounce the flash and use a diffuser?

To define the subject good.

7– What is a slave?

A flash unit that attaches to modern cameras for added lighting versatility.

8-What should you do if your image comes out too dark or too light?

Use external flash