Exposure Lock (AE-L Button) is the abbreviation stands for Automatic Exposure Lock. It is useful using automatic and semi-automatic shooting modes. Many DSLR cameras have a button that is named AE-L. If you use the manual, automatic or semi-automatic shooting modes, the display is automatically recalculated at every moment according to the scene. When you are in a situation where you have to make sure that the exposure is correctly calculated for the portion of the scene that you consider to be important, this exposure lock by AE-L button is important.
Basics of Exposure Lock (AE-L Button)
How many times you have took a photo, where the main subject appeared underexposed (or too dark) or overexposed (or too light)? It is a phenomenon that occurs easily when a major part of the picture is much more or much less luminous than the subject that interests us. For example, we can think of a portrait that has sky as background and take that the sky of a very sunny day or to a photo taken in the direction of a window from the inside of a room. In the first case, if the sky will be correctly exposed, the face will be very dark. In the second case, if the window takes the majority of the scene framed, objects outside will be exposed properly, while the objects inside will be very dark.
If you use shooting modes above, the display is automatically recalculated at every moment according to the scene. When you are in a situation similar to those described earlier in this article, you have to make sure that the exposure is correctly calculated for the portion of the scene that you consider to be important, not the one which is important calculated by the camera. However, until you change your composition, until you change your shotting mode, the camera will not change its interpretation of the scene. You will need to :
- Change the composition, so as to make the camera portion preponderant that is also predominant for you, press the button to lock the exposure, recompose the scene as you wish. We see below how to apply these steps in detail.
So this is the basic reason or situation where we use the Exposure Lock (AE-L Button).
Exposure Lock (AE-L Button) : How to Use the Exposure Lock
The crucial part is to make the preponderant part of the scene you want to be properly exposed. The easiest way is to get close enough to fill the frame with the subject or the person for whom you want to measure the exposure. Once locked, the camera will calculate the exposure correctly and you can press the AE-L. At this point the display will be locked, and you can step back, recompose and get the desired result.
In cases where you can not get close enough, the right thing to do depends on the exposure metering as choice :
- If you are using spot metering, move the point of focus on the subject you want properly exposed, so the camera will calculate the exposure for that precise spot (note that the spot size may be too small and therefore the exposure, however may be wrong )
- If you use the center-weighted metering, the center of the photograph will be properly exposed,
- If you use matrix metering, move the point of focus as in the case of spot metering, but it might not be enough, maybe you still have to get as close as possible.
In each of the three cases mentioned above, after making the changes in the composition, press the AE-L button to lock the exposure, then recompose as you wish.
For example, in the case of portrait, if you are using matrix metering, approach to fill with the face of the person to be portrayed in the entire frame. At this point press the AE-L and then go backward again so as to include the background that you were considering before in the composition.
If you use the manual shooting mode, exposure lock becomes totally superfluous. Using exposure lock can become crucial in many cases, to obtain results similar to that we desire. Unfortunately, in situations where a portion of the image is much brighter than the other, when one of the two is properly exposed the other is much more underexposed or overexposed. Unless you use a flash this difference can not be canceled. The exposure lock, however, allows to properly expose at least a portion of the scene that we want.