What About Exposure Compensation?
If you have previously been metering with Program mode or either Aperture or Shutter priority, you may be accustomed to using the Exposure Compensation control to get results that are to your liking. If you've noticed, in last week's explanation of Manual metering , I made no mention of Exposure Compensation. That's because with Manual exposure, it is pretty much useless. Here's the scoop:
What Exposure Compensation does in any mode is to artificially affect the meter by the inverse of whatever you set it at. For instance, if you set Exposure Compensation to +1, you are telling the meter you want an extra stop of light. This means that the meter will now see "medium" toned subjects as being one stop under, forcing the camera to compensate by giving you one stop of extra light. As with many aspects of exposure, it seems backwards at first, but actually makes complete sense once you think about it. Really, it does.
Exposure Compensation works quite well as long as the meter is coupled to the resulting exposure the camera uses, but in Manual exposure, you are in charge, not the camera. In Manual mode, you can see the graphic meter display ranging typically from -2 to +2, and if you change the Exposure Compensation control to +1, you will be able to see the meter reading go down one stop. But the shutter speed and aperture are both under your complete control. If you don't change them, nobody will, and the fact that the meter changed has no bearing on anything. You would still need to change the exposure yourself by adjusting either the aperture or shutter speed.
It does work of course: if you are shooting in Manual and set the Exposure Compensation to +1, then adjust your exposure to re-zero the meter when pointed at your subject, you will get a result that is one stop over medium, but you could accomplish the same thing by simply adjusting the meter to read +1 without the Exposure Compensation at all. The later is much more intuitive to me at least, and saves a step as well.