Copyright Michael Karbo, Denmark, Europe.
Chapter 21. A conclusion to metering
All photographers can take successful images by using the automatic programs while there is a lot of light in the middle of the day. But if you restrict yourself to only take photographs under these conditions, you won’t be able to take a fraction of the exciting images, which all kinds of other conditions can offer.
Figur 81. Buttons for activating the AE Lock and exposure compensation. Two important tools for correct exposure in difficult conditions.
Limitations of the automatic functions
All cameras have automatic exposure meters and most of them use advanced systems with segment metering. These systems have very different names like matrix, multi-segment, evaluative, D-ESP, etc., but they all work almost in the same way. They are good enough for most photo jobs. They ensure reasonably good exposures so that the images are neither underexposed nor overexposed.
If the lighting conditions are a little out of the ordinary, however, problems can easily arise with these automatic exposures. This is easy to see on the LCD screen when the image is displayed right after the exposure has been taken. A solution for this could be spot measuring. Here you measure the light yourself in the section of the image you want to be correctly exposed. If the section is not in the middle of the image, then you use the exposure lock (AE lock).
It is absolutely impossible to use light metering with some subjects. Images of fireworks, for example, but also subjects with enormous contrast and exposures taken in the evening or the morning can be very tricky. You can only try your luck here and take several different exposures.
There are two other options for finding the completely right lighting for an image both of which will be described in more detail later in the book. With Exposure bracketing a camera takes, for example, five images right after each other with different settings. Two of them are underexposed and two others are overexposed; so it is up to oneself to select the best exposure.
Finally you ought to be aware of the options in a RAW format. When these ”raw” files are processed in a computer, the exposure can be altered up to plus/minus one and a half diaphragm step, without any real damage to the image quality. So if you take images in RAW, and use, for example, Adobes plugin, then there is suddenly a big margin for the exposure. You can simply compensate after having taken an exposure
Figur 82. Ways of controlling exposures.
The shooting modes
Most cameras have several exposure programs, all of which can be used to find the perfect setting for a camera. The whole idea of exposure programs is that you can preprogram a camera for particular working conditions.
Sometimes a photographer would like to be able to take quick exposures without any fuss. In that case, he uses the automatic program. In another situation the photographer has more time to adjust his camera settings; in which case he uses one of the manual programs.