more than one person...who to focus?

[paigew]

If I am shooting more than one person is it best to put the focus point on the person farthest away or closest? Obviously the aperture value would be small enough to get both in focus. But who gets the 'best' focus? Should I still try to get the afp on at least one person's eyes?

 

[KmH]

You need both peoples eyes sharply in focus.

To do that you have to use sufficient DoF (depth-of-field).

DoF isn't only about the lens aperture. The focus point distance, lens focal length, and focus point to background distance also have to be managed by the photographer.

 

[paigew]

Thanks Keith, but isn't it true that the SHARPEST point of focus is where the actual 'point' falls? That is basically what I am asking...where do I put the point?

 

[fokker]

It is my understanding that if you focus on the closest person, the furthest person will be more in focus than if you did the other way around. I could be wrong about that though...

 

[KmH]

Yes. There is only 1 point, it's actually a plane that is roughly parallel to the image sensor, which is why DoF has to be sufficiently deep. You also have to consider that the DoF distribution usually isn't 50/50 in front of, and behind the point of focus.
As a general rule, the DoF distribution is such it is deeper behind the point of focus.

The point of focus you wil need to use will depend on the set up for the shot. No one here can tell you where to put the point of focus without an example of the shot set up.

 

[MReid]

It won't be the same every time, depends on the subject etc etc.
Generally if you want them all in focus, try to line them up so they are approximately in the same focal plane. focus on the middle distance one.
The depth of field will vary depending on how close you are to the subjects, the mm of the lens, and the aperture.
Someone will come on here and say that the depth of field is deeper behind the focus point than it is in front of the focus point....that may be true in a perfect world.....here in the real world where we all live, the focus plane and actual focus point will vary between lenses and cameras.

Speaking from my own experience, I never shoot above f4 and usually shoot at 1.8 or 2.8 so I naturally maneuver myself and my subjects to be in the same focal plane, as much a possible.
In a pinch or if you are in a hurry focus on the most important person that you want to be in focus.

 

[jake337]

Try to keep their eyes on a parallel plane. Or use a tilt shift lens to tilt the plane of focus.

 

[analog.universe]

You will get 1/3 of your field in front of the focus point, and 2/3 behind. Unless people are running around or something, I prefer to manual focus my shots, and I just place the focus plane 1/3 the way from the near person to the far person. If I was autofocusing, I'd probably focus on the nearest person, and then manually nudge the plane back (if your lens permits manual focusing in auto mode).

 

[paigew]

Thanks for all responses! Since I mainly shoot my kids they are NEVER 'set up' and I am always running around after them. I usually am toggling between af points.

 

[Big Mike]

You might also check out a DOF calculator .

 

[paigew]

thanks mike! so what person would you place the focus point on? the middle? or does that not matter?

 

[MReid]

If people are moving around, track the person you most want in focus.
Do you understand the charts Mike put up? Look at them closely, they explain it well.

 

[paigew]

Yes I think I understand DOF pretty well. I have seen these charts before. I know that if you use dof correctly both people will be in focus BUT my main question was where to place the point. I suppose in the long run it doesn't really matter that much if all the people are focused. Maybe I am overthinking it.

 

[MReid]

It goes back to the shot set up each time. When I say set up I mean arrangement of subjects at the time you click.
Try to get them all in the same focal plane as much as possible and focus on the one in the middle of the depth of field....assuming your equipment is focusing and set up properly there should be more depth of field behind your focus point than in front of it.

It will also matter how you want to frame the subjects and your focus method.....generally stick with focusing in the middle frame and middle depth of field.

 

[KmH]

You will get 1/3 of your field in front of the focus point, and 2/3 behind.

That is only true when the point of focus is not close to the camera, or a small lens aperture is used.

A 50 mm lens on a crop body camera, set to f/4 and with the point of focus 10 feet from the image sensor will deliver 45/55, not 33/66. But change the aperture to f/16 and then it's 33/66.

An 85 mm lens, at f/4, and 10 feet to the point of focus delivers 48/52, and at f/16 delivers 44/56.

So for most portraiture, particularly where he camera is close to the subject, the DoF will be much closer to 50/50 than 33/66.