Newbie question on 40D AF

Hi guys,

Just received my new 40d 3 days ago I am still over the moon, its such a good machine.

one thing it does confuse me a bit is the AF points system of the 40d. I read through the manual a few times on that section but still can't be cleared on my head.

if i select all 9 points as the af point do all 9 points suppose to be lighted up red when focus? or it will only pick up a few points here and there where the contrast are strong?

thank you

EGD wrote in post #5930968
Hi guys,

Just received my new 40d 3 days ago I am still over the moon, its such a good machine.

one thing it does confuse me a bit is the AF points system of the 40d. I read through the manual a few times on that section but still can't be cleared on my head.

if i select all 9 points as the af point do all 9 points suppose to be lighted up red when focus? or it will only pick up a few points here and there where the contrast are strong?

thank you

Correct...you will get only a few points light up.

I very rarely use all 9 points auto focus, instead I will select the single point that I need at that time.

thank you,

so even i select only one point i can still hold the shutter half way to lock the af and recompose?

Yes. Although try to select the AF point closest to your subject.

michaelgreen78 wrote in post #5931438
Yes. Although try to select the AF point closest to your subject.

cool, so the closer the focus point to the subject the more accurate AF will be after recompose.

can similar effect be achieved in manual focus mode too? like locking the focus and recompose?

EGD wrote in post #5931749
cool, so the closer the focus point to the subject the more accurate AF will be after recompose.

can similar effect be achieved in manual focus mode too? like locking the focus and recompose?

For manual focusing with AF on the shutter button, you’ll have to turn the switch on the lens to MF.
But, if you set C.Fn IV-1 to 2 or 3, you’ll be able to lock focus with AF-On button in the back, recompose and shoot without fiddling with the switch on the lens.
If you have lens with Full Time Manual focusing, you can touch up focus by hand..
This is very usefull for Live View shooting..

Try this, too, & see how you like it.
Post # 16: AF Point selection for sports