Manual simply means 'YOU set THREE parameters in the exposure triangle'...plain and simple.
How do you set three parameters?...well you simply set one of them (most traditionally ISO, by choice of film purchased and loaded or simply by first choosing an ISO to set in a digital camera!) and then...
SET the aperture and shutter speed numbers that the meter in the camera displays to you in the viewfinder!
(Gosh, not that hard, was it?!)
The mystical Auto modes is not mysterious if you know that it simply SETS one, or two, or three of the parameters of the exposure triangle! Assuming that you had selected what ISO value...
- Program mode sets TWO for you (aperture and shutter speed)
- Av mode sets ONE for you (the shutter speed)
- Tv mode sets ONE for you (the aperture)
- Manual mode sets NONE for you (since YOU set all three)
...the same as if you read the numbers and cranked dials to do it manually! 'Auto' vs. 'Manual' is the 'Automation of SETTINGS'! The camera can do the settings, or you can do the settings -- both -- (an important concept to burn into your brain) per what the meter suggests. Metering is identical whether you are in Auto or in Manual!!!
Now that the mystery of Manual has been dispelled, now we delve into some of the mysteries of 'Metering'...
- Metering assumes the target area averages to 18% tonality (about the greyness of the 'Reply to Thread' button on this forum at the upper part of the page.
- If your target is brighter (higher tonality value, like 70%) or darker (lower tonality value like 10%) than the 18% grey, you need to set Exposure Compensation to tell the meter "The subject/scene is brighter (or darker) than 18%...by this amount" For example, if you aimed at a white wall, the meter would ordinarily suggest some exposure combination which makes the white wall appear to be 18% grey in the photo...you tell the meter EC +1.66EV, or "the target (wall) is brighter than 18% grey by 1.66EV", and then the white wall looks white in the photo!
In Manual, which does not use the EC control to tell the meter to "give more exposure" or "give less exposure", you simply set the indicator mark to be not 'centered' but 1.66EV to the right of center (in the case of the white wall), and you have accomplished the same thing as choosing Av or Tv and also setting EC = 1.66EV. Now no more mystical wonder about Exposure Compensation!
Last edited by wiltw; 01-25-2014 at 07:59 AM. Click to view previous post history.