I recently purchased my first lens with a "real" manual focusing ring (Canon EF 85mm f/1.8 USM). Question: when I manually focus, I can turn the ring past the minimum/maximum markings on the distance window (no focusing occurs before the minimum focus distance or after infinity, of course). Is this action normal, and will it damage the focusing mechanism?
Got a tip for us?
Let us know
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Manual Focus Question
- Thread starter supergrandma
- Start date
- Sort by reaction score
It won't damage the lens, you can rotate the ring a full 180 degrees or more (not sure why you'd want to if it's not doing anything).
If it was going to damage the lens, they'd make it so you couldn't turn it any further and give you a warning in the manual.
SLC
If it was going to damage the lens, they'd make it so you couldn't turn it any further and give you a warning in the manual.
SLC
Thanks. It just kind of freaked me out when the focus ring turned past infinity. I'd hate to ruin a $350 lens after only a day.
He's referring to the physical turning of the ring past any sort of focus distance. Full-time manual focus lenses allow you to do this (that I know of). Quite a difference from the non-USM/FTM lenses, eh?
I'm aware of that- I was just pointing out that not only does the ring turn beyond "infinity", the lens will actually focus beyond infinity as well. There are multiple reasons for this but for example many zoom lenses are varifocal, or the cushion is put in to account for thermal expansion in different environments or manufacturing tolerances. This is important to realize because if you are looking for maximum focal distance from the lens cranking the ring all the way to the stop probably isn't going to work.
http://www.panoramas.dk/technics/focus.html
Ruahrc