What’s the difference between half-pressing the shutter and using AE lock?
Asked 4/26/2012
4 views
2 answers
0
On a Canon Rebel XS (1000D), I understand that half-pressing the shutter button meters the scene and may also lock focus so I can recompose before taking the shot. The AE lock button also seems to lock settings for recomposing.
Are these effectively the same, or does AE lock behave differently? I’m especially wondering whether the difference is mainly that AE lock can hold the settings even if I release the shutter button, and whether focus and exposure locking depend on camera settings.
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
14y ago
2 Answers
4
When you half-press the shutter, the camera meters and locks focus assuming you are in single-shot focus mode. After the shot is taken, the meter resets and the camera is ready to focus again.
When you press the AE button what happens depends on the camera and its configuration. If the button is set to lock:
- Exposure & Focus (AE-L / AF-L) then the behavior is almost the same as pressing the shutter halfway. The difference is that if you let go without fully pressing the shutter, exposure is still locked.
- Exposure Only (AE-L) then you can meter from one area using the button and focus from another using the shutter-button.
- Focus Only (AF-L) then you can focus in one area using the button and meter from another using the shutter-button.
You are also free to keep the button pressed while you take multiple shots and the exposure will be kept locked across shots. On Canon DSLRs, the usual behavior is to keep the lock after the button is released until the shot is taken. Other manufacturers default to the opposite which releases the lock as soon as the button is released but it is customizable at least on mid-to-high-end models.
Advanced cameras add way more capabilities to that button and sometimes have separate AE-L and AF-L buttons. For example, you can set the AE-L to use a different metering system which I find very practical for activating spot metering rather than keeping the camera in in that mode which is less practical. Sometimes AF-L can be set to disengade autofocus rather then focus, allowing manual focus without a lens with quick-shift.
Originally by user1620. Source · Licensed CC BY-SA 4.0
user1620
14y ago
0
Generated from our catalog & community — verify before relying on it.
They can be similar, but they are not always the same.
With a half-press of the shutter, the camera usually meters the scene and, in single-shot AF mode, locks focus. This lock is typically temporary: once you release the button or take the shot, the camera returns to normal operation.
The AE lock button’s behavior depends on the camera and how it’s configured. It may be set to lock:
- exposure only
- focus only
- both exposure and focus
The main practical difference is control. AE lock can let you lock exposure from one part of the scene, then recompose and focus elsewhere. On some cameras it can also hold the lock even after you release the shutter button, or work as a toggle depending on settings.
So: if your camera is set to lock both exposure and focus on a half-press, the result may feel nearly identical. But AE lock is useful when you want exposure and focus handled separately, or when you want the lock to persist while recomposing or shooting multiple frames.
Recommended products
UniqueBot
AI14y ago
Your Answer
Related Questions
What does an AE/AF lock button do that a half-press of the shutter doesn't?
How do AE-L/AF-L and AF-ON differ from focus-and-recompose, and when should you use them?
What does AF-L do on a Nikon, and why use it instead of half-pressing the shutter?
Can the Nikon D3100 use back-button autofocus and still fire the shutter after recomposing?
Canon 600D: can AE lock and flash exposure lock be used together in Av mode?