focus question

hi everyone,
I have question about focusing.When you want to photograph two people in a picture but one is closer to the camera, and the other is a few feet behind that person, how do you get both of them in focus? thanks.

You increase set the f number to F8+ - this depends on how far apart they are and what the lens is.

Roger

Yup...the smaller the f/stop,(bigger number) the more depth of field you'll have.
Aside from using smaller f/stop you can try to get your focus in between the two or use manual focus.

frog's explanation may have been a little confusing, but because the system is a little strange too, and is backwards from what you would think.

To achieve more depth of field (the range of distance of accepted sharpness in a photo) you need to make the opening of your lens smaller. This will require the camera to expose for a longer period of time to get the same amount of light as usual because the light is traveling through a small opening. But when you make the opening smaller (aka stop it down) it gives you more depth of field. WHat is tricky is that if you want a bigger opening, you have to use a smaller "aperture" on your camera. f/2.8 would mean the lens opening is much bigger than f/11. So if you want more depth of field, you want to close the lens more, and pick a larger f/ number. But remember, you need a longer shutter speed (the camera will be exposing for longer) every time you stop down the lens.

Good points brought up about how it all works, and it's important to understand. If it were me, at a "normal distance" of say 8-12' away I'd focus on the closer person and probably use f8 as well.

There are two reasons I'd focus on the closer of the two people. First, there will be a bit more depth of field beyond the focus point than in front of it. If they were 3' away and it was really critical, technically you should focus 1' beyond the closest person (2' ahead of the farthest). Second, if I didn't get my depth of field right and had to pick which person would be sharpest it would probably be the closest...

thank you so much everyone, your replies have been really helpful. :)

Changing the depth of field makes a lot of sense to me.
And so technically I should place my focus point pretty much in between the two people (but as AV said, another option is to focus on the closest person to the camera); is that the same idea for manual focusing as well?

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Originally Posted by PhotoGirl

And so technically I should place my focus point pretty much in between the two people (but as AV said, another option is to focus on the closest person to the camera); is that the same idea for manual focusing as well?

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Yes. Depending on the shot, you may need to do this with manual focusing. You'd have to have something in just the right spot for AF to work. If it's that critical, I'd really choose manual focus by first focusing on the closest person and then turning the focusing ring to focus just slightly farther than that point. Or truthfully, I'd just leave my focus on the first person... :)

thanks another view. :)