How to Pre-Focus?

[tbs]

Okay, so how do you literally "pre-focus"? How do you lock the lens/camera so it doesnt refocus on a spot youve focused/locked on?

I know its a easy question which I should know the answer to, but its something I havent done before

 

[Raikiri]

I assume you mean focussing and then recomposing the shot?

If it's a DSLR:

Set the focus mode to single shot
Only use the centre focus point
Focus and recompose while holding the shutter half way
Press fully to take the shot

 

[ScarySquirrel]

Or change the lens to MF once you have focussed in AF.

 

[tbs]

this is on dSLR, is this basically what "pre focusing" is? I was reading about that you can "lock" the focus on the camera (on the camera body itself or lens via the AF/M switch?)

 

[syke]

Or change the lens to MF once you have focussed in AF.

That's the way I do it, stops me accidentally pressing the shutter and focusing it again.

 

[famas]

i use the AF-L button? do not all cameras have this?

 

[tbs]

i use the AF-L button? do not all cameras have this?

I have a 350D and it doesnt appear it has, which is why i was wondering if the Lock was only on higher models. What camera do you have?

 

[Mr Jones]

I remember the Canon 20D have one, it's AF-L/AE-L. I had to turn it on to AF-L in custom menus. The same for the Olympus.

 

[famas]

thats a shame, i find it quite a useful feature. I have a nikon D90

 

[tbs]

thats a shame, i find it quite a useful feature. I have a nikon D90

I think the 450D probably has it though

 

[Gaffer]

Okay, so how do you literally "pre-focus"?

Other people have answered your question, but I am going to suggest sidestepping the problem in the first place.

Right now, your shutter button does 2 things:
- Focus control
- Shutter control

Most pro bodies have an AF-ON button on the rear and many folk turn set the shutter button to *only* work the shutter.

There is probably a way to do this on your camera by re-using one of the other buttons that you are probably not using. Have a good dig round the custom functions. That way, the camera will only focus when you explicitly tell it to focus. You don't need to switch between one-shot and AI-Servo any more either - leave it in AI-Servo all the time and use the button to control when you want it to use it.

Andrew

 

[asim18]

i use the AF-L button? do not all cameras have this?

Yeah I use it too, on my d40x.

 

[russ0r]

I think the 450D probably has it though

Yeah you can set the * button on the back to do AE or AF lock on the 450D. Pretty handy