Canon PowerShot S100 DIGITAL ELPH User Manual page 26

24 Basic Functions
About the Autofocus Function
This camera employs AiAF (artificial intelligence autofocus) technology
which uses a broad metering field to calculate the focal distance with
high precision. It delivers a crisp focus even when the photographic
subject is slightly off-center.
Using the Focus Lock
The following types of subject may not be suited to autofocus
photography. Use the focus lock in these situations.
• Subjects with extremely low contrast to the surroundings
• Subjects with extremely bright objects at the center of the
composition
• Subjects that are moving quickly
When recording through glass, try to shoot as close to the glass as
possible to reduce the chances of light reflecting back off the glass.
How to Use the Focus Lock
1. Aim the camera so that a subject at the same focal distance as the
main subject is centered in the brackets in the optical viewfinder.
2. Press the shutter button halfway and wait until two beeps sound.
3. Re-aim the camera to compose the shot as desired and press the
shutter button all the way.