If the batteries do fail, the EF can still be used manually from 1/ 2 - 1/1000 sec. The Variable Aperture AE control will not operate, but you can manually adjust the aperture ring of the lens. A basic exposure guide to follow for bright sunlight (with distinct shadows) is to make a fraction representing the shutter speed needed at f/16 by putting a "one" over the film's ASA rating.
This indicates that the film has left the multi-slot take-up spool. Turn the rewind crank one or two more revolutions to completely rewind the top of the film leader back into the cartridge. The pull up the rewind knob to open the camera back and lift out the cartridge.
Lenses that support changes in the AF speed Extender 1.4 x EF-S 10-18mm f/4.5-5.6 IS STM EF -S 15-85mm f/3.5-5.6L IS USM EF-S 18-55mm f/3.5-5.6 IS STM EF-S 18-135mm f/3.5-5.6 IS STM EF-S 55-250mm f/4-5.6
