You really need to take a meter reading, with the meter set for your film speed. A small aperture like f16 or 22 will give good depth of field meaning that the subject will be in focus from close to the camera into the distance( depending on how you set the focus). Sharpness is normally best from about two stops down from maximum aperture, and falls off towards the smallest aperture. There are some good books available on the subject of exposure that may help. Check Amazon, although I pick up lots of photo books in charity shops. Alex