Canon EOS 5DS R Instruction Manual - Page 123

3 Customizing AF FunctionsN 24 Lens drive when AF impossible If focus cannot be achieved with autofocus, you can have the camera keep searching for the correct focus or have it stop searching. ON: Continue focus search If focus cannot be achieved with autofocus, the lens is driven to search for the correct focus. OFF: Stop focus search If autofocus starts and the focus is far off or if focus cannot be achieved, the lens drive will not be performed. This prevents the lens from becoming grossly out of focus due to focus searching. Super telephoto lenses, etc., with a wide focusing drive range can become grossly out of focus during focus search, taking more time to achieve focus next time. Setting [Stop focus search] is recommended. 123