|
I thought once the focal length changes, then the need to focus changes.?
That's why at 50mm, your 18mm focus was way off, because it's not correct for 50mm.
So in effect, you're doing the following
Adjust to 18mm
Auto Focus to 18mm
Adjust to 50mm
Auto Focus to 50mm
Switch to manual
Adjust to 18mm and take the shot (with a focus that is correct for 50mm).
|