Stay at home
- Aug 16, 2012
The geek came out and I measured the focus breathing. The minimum focus distance of mine on a 5DSR set at 400mm is 970mm, close to the specs of 975 with a magnification of 0.312x, the same really as the specs of 0.31. The calculated focal length is 178mm, instead of 400mm, at the mfd. Putting the camera (sensor) at 1.6m from target, the focal length is 228mm. (magnification 0.16x)There’s a huge amount of focus breathing with the 100-400mm II as you get down to its mfd of 1m. From what I remember, the focal length nearly halves.