How to adjust SLR, AV file, F value and iso?

Mainly depends on what scene to shoot.

1, night shooting, if you don't turn on the flash, you can turn down the EV 1-2, and the iso is controlled above 800.

2, the light is enough to take portraits or close-ups. You can set the aperture priority, that is, the AV file on the turntable, and the machine will automatically adjust the shutter and iso according to the external light.

3. The use of iso also needs to distinguish scenes. Generally, if the daily light is sufficient, it is around 100, and it is 200-400 indoors. If the light is insufficient, try adjusting it to 800= 1600. Ordinary SLR. There will be obvious noise above 1600.

These parameters don't have a definite value, so we need to take more pictures and learn more.