Auto Exposure Lock
There are 2 basic functions that you can use the AEL (Auto Exposure Lock) button for depending on what mode your camera is in, and if you have a flash active or not.
|AEL||In the capture modes the AEL button Locks the Auto Exposure, while allowing the Autofocus to function, making it possible to maintain the same exposure while re-framing the shot so as to get a better composition.|
|SLOW SYNC||With the camera set to Program or Aperture Priority modes, the same button allows using the flash in Slow Sync mode, all the while retaining the exposure metered under ambient light.|
I wrote a bit about Slow sync a while back so today I only want to talk about “Auto Exposure Lock”
What does it do?
Its very simple. When I press the AEL button it takes my current (in camera) meter reading, and locks it at the same setting for every photo I take until I change it back i.e. My camera is in A mode and set to ISO 200 F/8. When I press the shutter button halfway down my camera will make an exposure reading and set the shutter speed it thinks is correct. I can now lock that exposure value in so that all my shots will be taken with the exact same settings.
But why would I lock my exposure?
One of the best examples of locking your exposure is for panorama photography. I can meter the scene I want to shoot with my camera and “lock the exposure”. That way every photo for the panorama will be taken with the same exposure value. This makes it a lot easier latter when I sew the images together. If I hadn’t done this then each photo would have been individually metered, and some of my images may be slightly brighter or darker than others.
This image is 3 photos joined together. First I metered the sky and locked the exposure. Then I took 3 photos (with a tripod) starting from the left hand side. It is also Important to check you have a bit of overlap, that way you have reference points where the images need to be joined together. If I hadn’t used AEL then the photos left and right would have had a different exposure value and I wouldn’t have a smooth exposure across the whole image.
What’s the down side?
The biggest problem is when you hit the AEL button accidentally, your camera will stay with the 1 exposure value for every shot until you change it back.
Depending on you camera type you may have an extra function available with the AEL button, when the camera is set to the playback mode it serves to zoom into an image under review up to 12X. The level of magnification is memorised and recalled the next time the image is displayed on the monitor. You can also use the button to test the wireless flash system to verify they are all firing before you take the shot .The AEL will trigger the modelling flash with the HVL-F58AM so you can see where the light is going to be on your subject when the flash is in Modelling flash mode. In some Alpha models you can also change user settings to Hold or Toggle, this is just a matter of preference.