I use the simple equations for a thin lens, as you can approximate the complex lens to this. If the lens has a focal length f, the distance from the lens to the subject is u, the lens to the sensor is v, then 1/v + 1/u = 1/f. The magnification m is given by m = v/u. The distance, d, to the subject is always measured from the sensor. So, d = u + v. You just do the algebra with these. Eg, if as I recall from memory, the magnification of the RF 100-300mm at the mfd of 1800 mm is 0.16, then u + 0.16u = 1800, so u = 1800/1.16, = 1552mm, v =248mm. So, 1/f = 1/1552 + 1/248.This is really interesting to me. Is there a Physics law or theorem I can learn to understand it more?
Upvote
0