What this article is about.This article isn't about Exposure or Calculating Exposure - that's a different topic. This article is about choosing which Exposure Mode you want to consider. That's the P A S or M on the camera's dial - (Canon users will recognise that as P, Av, Tv and M).
This article isn't about the Variables of Exposure
- ASLL - Actual Scene Light Level (sometimes quantified as EV number at ISO 100 - e.g. 2 or 16 - 2 being darker than 16)
- Aperture (otherwise known as the f/no e.g. f/2.8 or f/16, f/16 being darker than f/2.8)
- Shutter Speed ( e.g. 1/30th sec or 1/500th sec, 1/500th being darker than 1/30th)
- ISO (or the sensitivity of the recording medium e.g. 100 or 1000, 100 being darker than 1000)
P A S
But should you use P or A or S?
P - for Professional
A - for Artistic
S - for Superfast
M - for Manual Exposure
- F/no - you adjust
- Shutter speed - you adjust
- ISO - you adjust
- Exposure Compensation - prevented from working.
- You heard "That's what the Pros use"
- You don't like what the camera recommends. And you don't like it by a lot - like EV + or - 3 or 4 - way past what the camera's dial can do under P A S.
- As you wave the camera at the scene, a slight change in aim point changes the CELL under P A S. - That usually means there is a light or sun in the scene, pointing into the camera's lens.
- You're using manual electronic flash
- You just feel like doing it.
The Take Home PointWhether you opt for P or A or S or M, the final chosen setting might be the same.
For a reinforcement information try Understanding Exposure