I was doing some testing to see how smooth the bokeh would be with my lens and subjects at different distances when I noticed something weird (to me). Basically by only changing the focus point in the frame is possible to see an element that was hidden with the focus point in another point of the frame.
My question: how does this happen?
Am a beginner, trying to learn. Am familiar with how aperture and focal length affect the focal plane, how a subject very close to the lens is going to make a softer background and how to play with focal length, aperture, shutter speed, ISO.
But have no clue why this is happening.
Here is the setup for the three pictures:
Shooting on a tripod
Camera Canon 80D with 18-135 STM lens
Focal length 135mm
Aperture priority mode. F/5.6
Live view mode (clicking on back lcd to change point of focus)
A Photo: Grey robot is named Jazz. Focus on his face. Distance from the lens to Jazz’s face 23cm.
B Photo: Blue Robot is named Soundwave. Focus on his face. Distance from lens to Soundwave’s face 83cm.
C Photo: Book with man on cover. Focus on man. Distance from lens to man on cover 137cm.
D Photo is a merge I did of A and C, showing how the bowl was hidden behind Jazz in A.
E Photo is showing the general setup.
Notice I did not do any cropping or other editing for A, B, C.
All settings and camera position are kept the same in A, B, C. Only the point of focus changes.