Was this slide every corrected? If I remember correctly the rays from $Z$ should actually cross before the sensor plane, right?
Edit: hmm nevermind, from this diagram is looks like the rays would cross before the sensor plane if $Z$ was further from the lens than $Z_{f}$ so the slide is correct.
lucida
This slide also explains how myopia (or near sightedness works). A nearsighted eye is longer than a normal eye, moving the sensor plane, i.e. the retina, farther back. This makes the focal length longer, so objects need to be closer to come into focus.
Was this slide every corrected? If I remember correctly the rays from $Z$ should actually cross before the sensor plane, right?
Edit: hmm nevermind, from this diagram is looks like the rays would cross before the sensor plane if $Z$ was further from the lens than $Z_{f}$ so the slide is correct.
This slide also explains how myopia (or near sightedness works). A nearsighted eye is longer than a normal eye, moving the sensor plane, i.e. the retina, farther back. This makes the focal length longer, so objects need to be closer to come into focus.