5D and focusing

[michael_ziegler2]

I am using a 5D and have the focus separated from the exposure button using the

* button. I have started using the AI servo tracking and am wondering if I must

continue to hold the * button down through out following the subject?

[jason_hall4]

Have you tried it to see?

[peterlyons]

Yes, you must. I use my 5Ds this same way, and I'm sure of it.

[PuppyDigs]

All EOS are that way from the time the CF4 * AF was introduced in the early 90s. The main

benefit is AF stops when you release the * button.

[peza]

In one word - yes. Which makes me also wonder why you ask about such a apparent (and in viewfinder visible) thing. CF4 * AF is wonderfull idea from Canon BTW.

[jason_hall4]

Where do you guys find it useful? I tried it once and found it terribly hard to use. I have logged a lot more hours with the camera now and may not find it such a pain to retrain my fingures if there was an apparent advantage to it. I assume there is an advantage otherwise folks would not love it so. Maybe it's my style of photography or some thing, but I just don't see it right now.

 

Maybe I should start my own thread on this.

 

Jason

[michael_ziegler2]

Jason,

By seperating the functions you can focus independent of your exposure reading rather than pushing one button which does both functions simultaneously. This can be a vital feature if for example you wish to expose off the sky and then focus on a persons face.

[sknowles]

Jason, I agree with Michael. I set the * button for AF so I can focus and then use the shutter

for the exposure, usually aperture priority. It's quick to learn and overcomes accidental

refocusing if you move the camera off the subject(s). The * button either continuous focuses

or locks it.

[jason_hall4]

I see. I guess what I have alway done was use the shutter button to get exposure (maybe of the sky while it also focused) then use the * button to lock exposure. Then I would reframe and refocus before exposure times out and shoot.

 

Thanks

 

Jason

[nevilleb]

Jason,<p>

 

Others have already mentioned why the * button is used to lock focus, and depressing the shutter button midway is used to lock exposure.<p>

 

I just wanted to add that locking exposure off another part of the scene and then recomposing is only valid if one is using partial / spot metering, not if the camera is set to use evaluative metering.<p>

 

Neville Bulsara<br>

India Photo Tours, Photography Workshops & Expeditions for the Discerning Photographer