You can either type numbers into the edit control or tap the drop down arrow and select the focal length from the list. You can also change units if you wish by tapping on the units drop down box. F Stop Enter the f stop for the lens here. You can either type numbers into the edit control or tap the drop down arrow and select the f stop from the list.
Resolution Enter the desired image resolution here.
You can either type numbers into the edit control or tap the drop down arrow and select the resolution from the list. You can change units if you wish by clicking on the units drop down box. The resolution you specify defines the maximum amount of blurring you are willing to tolerate at the film plane. The higher the resolution you specify, the sharper you are requiring the image to be and the narrower the depth of field range that will satisfy that requirement. The circle of confusion is defined as the diameter of the circle that an ideal point on the subject is focused to on the film plane.