Staying Focused With AF & MF

[Colin Campbell]

Does focusing with the manual focus ring do any damage to a lens when it is in the Auto Focus setting? I find myself doing this quite a bit (from force of habit) but have never seen anything definitive on the effects of this practice.

[matt wilson]

It depends .Some lenses have full time manual focus .In those you can overide the autofocus using the manual ring .(often the more expensive lenses)

Other lenses you have to dsiengage the autofocus first .If you don't it is highly likely you will wreck the focus motor due to you manually applying a force against what the motor wants to do.

Moral .be absolutely sure your lense supports the facility to avoid an expensive mistake.

[Colin Campbell]

Originally Posted by matt wilson

It depends .Some lenses have full time manual focus .In those you can overide the autofocus using the manual ring .(often the more expensive lenses)

Other lenses you have to dsiengage the autofocus first .If you don't it is highly likely you will wreck the focus motor due to you manually applying a force against what the motor wants to do.

Moral .be absolutely sure your lense supports the facility to avoid an expensive mistake.

I am sure many people manually adjust their lenses whilst in the AF setting but are probably saved by their tender touch!

It would be very helpful if the documentation that accompanies lenses made it very clear what the situation is as regards AF and MF, and maybe a small warning on the lens itself would be helpful.

[chris-p]

A good rule of thumb is the type of drive mechanism. If they're older screw drive lenses then they are easy to damage by manually focusing them withough disengaging the AF drive motor.

[HDPete]

Whilst on the subject of Full Time Manual focus override...

I've not had much joy with this as the camera always overrides my manual override.... Is there a focus setting in the menus?

[chris-p]

AFAIK there isn't a setting in the menu. It sounds like you're using AF, letting go of the shutter and tweaking then pressing the shutter again. That would cause the camera to start the AF off.

You need to either turn the AF off or half press the shutter and then adjust the focus manually. You can do that even while the AF system is still trying to focus - it'll just stop, but as soon as you press the shutter again you'll just start the AF system.

[OldBoy]

Some cameras have a lever/switch next to the lens opening on the camera. This allows you to put the lens into manual mode so that you have to set the focus manually. This only effects the lens operations.