To lock the focus, change the mode from Auto to Manual. In focus-aid mode, the focus indicators inside the finder works when focused manually. This function is handy when you want to focus on one particular spot after having autofocused on the whole area. Focus-aid function also acts as an effective teaching aid. Autofocus has recently become even more important in fundus photography.
Autofocus effectively solves the problems of operator's eye-fatigue which affect focusing.
Autofocus minimizes the problems of diopter adjustment for each operator when many different operators share one fundus camera. Autofocus lowers illumination level as required, minimizing patient discomfort. The NF-505AF provides a shortened distance to the patient, while retaining a long 50.1mm distance to the cornea. This makes examinations as easy and comfortable as possible. Eyepiece height is lowered to 523mm making camera operation easier.