Nikon Zoom 310 Af Manual -

: Active autofocus with a focus lock feature and a minimum distance of approximately 0.6m (1.96 ft).

Since the original paper manual is lost to time for most units, here is the community-sourced repair guide. Nikon Zoom 310 Af Manual

is the official hub for modern digital manuals, though legacy film camera manuals are often found in their archive sections. : Active autofocus with a focus lock feature