Canon EOS 70D Operation Manual - Page 241

Using AF to Focus (AF Method) Shooting Conditions that Make Focusing Difficult Low-contrast subjects such as the blue sky, solid-color flat surfaces or when highlight or shadow details are lost. Subjects in low light. Stripes and other patterns where there is contrast only in the horizontal direction. Subjects with repetitive patterns (skyscraper windows, computer keyboards, etc.). Fine lines and subject outlines. Under a light source whose brightness, color, or pattern keeps changing. Night scenes or points of light. Under fluorescent or LED light sources and when the image flickers. Extremely small subjects. Subjects at the edge of the picture. Subjects strongly reflecting light. The AF point covers both near and distant subjects (such as an animal in a cage). Subjects that keep moving within the AF point and cannot keep still due to camera shake or subject blur. A subject approaching or moving away from the camera. Autofocusing while the subject is very far out of focus. Soft focus effect is applied with a soft focus lens. A special effect filter is used. Noise (spots, banding, etc.) appears on the screen during AF. 241