Question

An f/2.80 CCD camera has a 105-mm focal length lens and can focus on objects from infinity to as near as 30.0 cm from the lens. (a) Determine the camera's aperture diameter. Deter- mine the (b) minimum and (c) maximum distances from the CCD sensor over which the lens must be able to travel during focusing. Note: "f/2.80" means "an f-number of 2.80."

Answer 1

Given that: - f/2.80 means the CCD camera has a f. number of 2.8 The f- number also defines speed of the lens and mathematically calculated as: N = Focal length/Aperture Diameter Therefore Aperture Diameter of CCD camera having focal length of 105 mm and f- number 2.8 will be 2.8 = 105/Aperture Diameter = > Aperture Diameter = 37.5 mm Thus, the Aperture Diameter is found to be 37.5 mm Since, the CCD camera can focus on objects form infinity to as near at 30 cm. the minimum distance from CCD camera over which lens must be able to travel during for using can be calculated using the lens equation, i.e. \r\n 1/f = 1/u + 1/v f: focal length u = object distance v = image distance Thus, the minimum distance will be: 1/105 = -1/300 + 1/u = > 1/v = 1/105 + 1/300 v = 150 + 300 /405 = > v = 77.77 mm Thus, the maximum distance