Canon eos 40d 1901b014 User Manual

80

Autofocus can fail to achieve focus (the focus confirmation light <

o>

blinks) with certain subjects such as the following:

 

Low-contrast subjects

Example: Blue sky, solid-color walls, etc.

 

Subjects in low light

 

Extremely backlit and reflective subjects

Example: Car with a reflective body, etc.

 

Overlapping near and far objects

Example: Animal in a cage, etc.

 

Repetitive patterns

Example: Skyscraper windows, computer keyboards, etc.

In such cases, do one of the following:
(1) Focus an object at the same distance as the subject and lock the 

focus before recomposing. (p.48)

(2) Set the lens focus mode switch to <MF> and focus manually.

 

Focus by turning the lens focusing 
ring until the subject looks sharp in 
the viewfinder.

If you press the shutter button halfway during manual focusing, the active 
AF point and the focus confirmation light <

o> in the viewfinder will light 

when focus is achieved.