1- External flash is typically used to capture fast-moving subjects or in low-light conditions.

2- No light metering is required when using flash as it does not rely on natural light.

3- Flash synchronization refers to the maximum shutter speed that can effectively work with the flash.

4- ETTL stands for Evaluative Through The Lens, a flash exposure system commonly used by Canon.

5- Shooting faster than the camera sync speed can result in an image with half dark and half visible.

6- Photographers bounce the flash and use a diffuser to soften the light and enhance the image quality.

7- A slave is a feature that enables triggering multiple flashes simultaneously.

8- Adjusting the aperture is recommended if the image turns out too dark or too light. Lower the aperture number for dark images and increase it for bright images.