Summary and Recommendations
To understand how different methods of exposure metering behave two principles are important:
- Exposure meters are calibrated in a way that they render subjects with very low contrasts as with medium brightness.
- The image sensor or your camera can render less differences in brightness than the human eye.
If contrasts are too strong you will inevitably have under- or overexposed areas where details are lost.
The different types of exposure metering differ in where they measure the exposure and how they combine the measured values:
Methods using multiple segments
- Brightness is measured at many places across the whole image
- complex logic is used to find a balanced exposure
- Brightness is measured only in a small area in the center of the image or where the autofocus has put its focus
- The spot where you have metered will appear with medium brightness in the image.
- Brightness is measured across the whole image but the center area gets more weight than the rest.
- Result: Medium brightness of your picture in case of low contrasts, and in case of stronger contrasts a brighter or darker main subject in the middle has a good chance not to get over- or underexposed respectively.
Depending on the situation the different methods need different compensations, but if applied correctly they all produce good results.
The modern methods using multiple segments are the most common ones but the others have their users too. It is a question of personal preference and habits – possibly acquired over years – how you summarize the following advantages and disadvantages for yourself:
|modern methods using multiple segments||spot and center-weighted metering|
|disadvantages||Results can vary depending on your shooting situation and cannot always be predicted accurately||needs more effort and background knowledge|
The auto exposure lock is a simple possibility to take influence on exposure metering by choosing the picture frame that the camera shall use for exposure metering. You can use it with any camera.
Now turning to the promised recommendations: It is impossible to put tipps into a short overview that are suitable for all kinds of individual preferences and shooting situations.
A small number follows that I believe to be relevant and practical but they need addition of further articles, examples and – above all – your own experimenting:
- With Nikon DSLR cameras you do nothing wrong if you trust the excellent matrix metering as the standard method of exposure metering.
For cameras of other manufacturers it will certainly be the same.
However if you prefer the other methods out of habit or other reasons and are happy with them, there is no reason to change habits.
- Be careful: There are entry level cameras that tend to produce overexposed areas more easily.
The reason will be that beginners are more pleased by an overall friendlier, brighter look of the images and do not complain so easily about blown out highlights.
- Even the most expensive camera needs manual exposure compensations every now and then.
If you shoot very subjects rich in contrast better check results and take a second picture if needed.
- Spot metering is a good alternative for subjects with high contrast and if you want to focus exposure really on a selected part while the rest can disappear in white over- or black underexposure.