# tried to manually focus an af lens



## choz (Dec 28, 2010)

so my lens [ef-s 18-55mm i.s. on a canon rebel t2i] was on auto focus and i attempted to manually focus it without switching it off [accidentally]..

i realized my error before i attempted with too much force.. and all was fine when i set it to manual..

am i correct in assuming it would take signifigant force to damage the focus motor.. or focus lock, or whatever it was that was stoping me from turning the focus ring?


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## oldmacman (Dec 28, 2010)

choz said:


> so my lens [ef-s 18-55mm i.s. on a canon rebel t2i] was on auto focus and i attempted to manually focus it without switching it off [accidentally]..
> 
> i realized my error before i attempted with too much force.. and all was fine when i set it to manual..
> 
> am i correct in assuming it would take signifigant force to damage the focus motor.. or focus lock, or whatever it was that was stoping me from turning the focus ring?



You should be able to freely rotate the lens barrel without any concern. I wouldn't be focus pressing the shutter release and manually focusing at the same time, but outside that I don't see an issue. Maybe someone else has more detail.


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## smlblk396 (Dec 28, 2010)

I don't think you can Manual focus and auto at the same time with that lens.


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## bazooka (Dec 28, 2010)

That lens does not have full time manual, so you cannot manually focus while in AF mode.  I don't know if it will damage it, forcing the motor to turn like that, but it sure makes a terrible sound.


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## Coog075 (Jul 5, 2011)

So Im bringing this thread back from the past. 

Anyone have any experience in accidentally turning the manual focus ring when AF was on? 
How much force did it take ... did it survive? 

I let my friend hold my camera and she accidentally turned the manual focus ring on the 18-55mm kit lens for my T3i. 
It seems to be okay. I hope it stays like that. 

Choz (OP) ... if you see this, was your lens okay after all? 

Thanks guys.


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## TwoTwoLeft (Jul 5, 2011)

The manual for the lens says not to do it. 


So don't do it...


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## Coog075 (Jul 5, 2011)

Thanks for the reply...but that didn't help....
No where in my post did I say I did it intentionally....

I'm asking if anyone had done it on ACCIDENT and did the lens still function properly after that...



TwoTwoLeft said:


> The manual for the lens says not to do it.
> 
> 
> So don't do it...


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## fokker (Jul 6, 2011)

Does the lens still work now? If so, then the lens still works and hasn't been damaged. Obviously.


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## den9 (Jul 6, 2011)

i thought this was ok? i thought by turning it you override the AF? i do it all the time actually. on my canon 17-40 and never had an issue.


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## Drake (Jul 6, 2011)

You can override the AF with the pricier lens using HSM/USM AF motors. Don't try it with the cheaper lens or it might damage the AF motor unabling the lens to autofocus anymore. Never happened to me or any of my friends, but I don't touch the focus ring when I am in AF mode. Of course I have accidentally moved the ring a couple times in the 18-55 IS which isn't hard to do since it's in front of the lens, but it turned only by a couple degrees and no damage was done. I am trying to be careful about it though.


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## den9 (Jul 6, 2011)

i see what you are saying now, the kit lenses dont really have focus rings and make a gear type of sound and dont move easily when trying to move on AF mode right?


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## subscuck (Jul 6, 2011)

den9 said:


> i see what you are saying now, the kit lenses dont really have focus rings and make a gear type of sound and dont move easily when trying to move on AF mode right?



Some lenses have full time manual over ride. This means you can MF anytime, even when the lenses are set to AF. This allows you to fine tune your focus in AF. Cheaper lenses, like a kit lens, have focus rings, but do not have full time MF, and can only be manually focused, without risking damage to the lens, when the lens is switched to MF.


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## 60Downer (Jul 6, 2011)

I have EOS 60D and tried to manually focus while still in AF.  You can sure tell that it is "still in gear", and resists turning.  I didn't read anything about NOT doing it, but my common sense told me that if I kept trying it, something was going to break.   I think something in the plastic gears would strip.  I am glad to read in here that someone said the lens manual says not to do it.  I won't do it.


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## Coog075 (Jul 6, 2011)

fokker said:


> Does the lens still work now? If so, then the lens still works and hasn't been damaged. Obviously.





The lens works... but immediately after my friend accidentally turned the MF ring while in AF... The lens seemed slower at focusing. 
Maybe I'm just paranoid... I hope I am.... 




@Drake: Thanks for your post. That's what I'm looking for. People who have done the deed and had no damage done. I too will be careful about the MF ring... and making sure anyone else who uses the camera is 110% fully aware of it.


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## vtf (Jul 6, 2011)

My 50mm 1.8 canon lens is full time manual now. I would consider doing that a grave error.


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