Ef 75-300mm f/4-5.6 iii specifications - imaging resource lens specifications. name, canon ef 75-300mm f/4- 5.6 iii. image circle, 35mm. type, telephoto zoom. focal length, 75 - 300mm. aps equivalent, 120 - ... filter size: 58mm lens construction: 13 elements in 9 groups dimensions(length x diameter): 122mm x 71mm / 4.8 in. x 2.8 in weight: 480g / 1.1 lb