I have a 750D (Rebel T6) and use it mostly with a 70-300 mm lens to take pictures of birds at a local reserve; often birds will take flight so I have the camera set to a high shutter speed and AI Servo; would focusing be better if I changed to One Shot or AI Focus instead of AI Servo for all other types of filming. I also use that lens to take close-ups of butterflies and the like; wearing glasses I find it difficult to see the focus indicator in the viewfinder – in manual a light flashes when too close and goes off when focus is attainable – so I have set the Beep to operate when focus is attained but nothing happens, is this a fault with my camera or is there anything else to set.
