Digital Camera World on MSN5 个月
How do you choose the right focal length of lens to use for your photography?
Choosing the right focal length is a crucial part of the creative decision making process for a photographer. You can have ...
Astronomy on MSN7 天Opinion
What is the difference between a 2″ eyepiece and a 1¼" eyepiece?
What is the benefit of a 2″ eyepiece compared to a 1¼” eyepiece? Tom NagyNorth Ridgeville, Ohio A 2″ eyepiece delivers a ...
BBC20 天
The lens power equation
\(power \ of \ a \ lens \ (D) = \frac{1}{focal \ length \ (m)}\) A lens has a power of -3.33 dioptres. Calculate the focal length and state what type of lens it is.