# Can a Lens be damaged when....



## Mantadude (Oct 10, 2017)

Hello,

Can a lens be damaged when you switch the lens to autofocus on the lens itself, but then manually focus it?

I am specifically looking at the Canon 100mm F2.8L Macro lens. I like to have it on auto focus as I can use the AF-ON button to get the focus close, and then manual to get it just right. I am also using this in a video setting.

Curious if I have been damaging my lens for the last 5 years.

-Dustin


----------



## Mikehit (Oct 10, 2017)

I believe the 100mm f2.8 has 'full time manual' which means it is designed for that. So do not worry


----------



## 9VIII (Oct 11, 2017)

The kit lenses seem to "lock" the focus ring when you switch it to AF, and forcing it would probably break the lens.
The 40mm Pancake with "Focus By Wire" allows the focus ring to spin freely at all times, but doesn't allow manual focus with the camera is on low power standby either (a big problem if you like to do Macro).

"Full Time Manual" means there's a clutch in the lens that allows manual focus at any time, with or without power, and you can even turn it against the AF motor without serious consequences (though I can imagine doing it too often might wear out the clutch mechanism).


----------



## kaihp (Oct 11, 2017)

Mikehit said:


> I believe the 100mm f2.8 has 'full time manual' which means it is designed for that. So do not worry



I have the 100L and it is indeed a full time manual lens. The lens is designed for this and turning the distance scale while in AF mode won't damage it.


----------



## Maximilian (Oct 11, 2017)

Hello Dustin! 



Mantadude said:


> Can a lens be damaged when you switch the lens to autofocus on the lens itself, but then manually focus it?


It depends on the lens model. You'll have to refer to the manual of that lens.



> I am specifically looking at the Canon 100mm F2.8L Macro lens.


One of my favorite life mottos is (in German):
"Nicht wer lesen kann, sondern nur, wer wirklich liest ist im Vorteil!"
loosely translated:
"The ability of reading is only an advantage if you really use it!".

So if you go to page 5 in the US manual 
http://gdlp01.c-wss.com/gds/2/0300003522/02/ef100f28l-macroisusm-im2-eng.pdf
you can read "full-time manual focus".

But there is always someone stupid enough to do the RTFM for you. 
You're welcome


----------



## Mantadude (Oct 11, 2017)

Thanks everyone. I appreciate. I had never even heard the term full time manual before. So thanks for the education. I had always just done that with this lens, as it never seemed like I was forcing it. So I figured it was okay. 

Thanks again for the info!
-Dustin


----------

