How to AF 2 objects at both ends?


#1
Hi...have a very newbie qns to ask. How can i take photos of 2 persons standing at both ends of the frame and the AF is on both?

Isit by locking AF on the 1st person then AF agn on the 2nd person? I'm not sure if this is the correct way to do it? How do you guys do it?

Much appreciated yr replies. thx
 

Numnumball

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Mar 6, 2009
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#3
Stop down to obtain a greater dof and read up on hyper focal distance :)
 

ziploc

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Jan 17, 2002
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#4
You'll need to choose an aperture that has enough DOF to cover the distance between the 2 persons. Where you focus (1st person/2nd person/middle) will determine how much DOF you need. Use this DOF calculator to help you.
 

Octarine

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Jan 3, 2008
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#8
Thx so much for all yr replies dudes! So meaning i can just af 1 person, provided they are of same focal plane + enuff dof? I assume u recomm single centre focus right?
Center focus when the persons are at both sides of the frame? :think:
Please consult your manual about selecting focus points. Together with read-up about DOF (as already recommended) you should be able to get it.
 

ziploc

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#10
Thx so much for all yr replies dudes! So meaning i can just af 1 person, provided they are of same focal plane + enuff dof? I assume u recomm single centre focus right?
i mean half press the shutter and af on either of the person first then re-adjust the cam to centre so that can "lock" the af?
If the 2 persons are at the same distance from the camera, you just need to focus on one. If they are at different distance, you'll need to ensure enough DOF as I mentioned.

If you need to know how to focus lock/using the AF points, please read your camera's manual as mentioned by Octarine.
 

Diavonex

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Sep 23, 2008
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#11
There are cameras that will pick out faces and allow you to asign focus priority.
 

#13
read this on why focus-recompose can pose a problem.
One way to solve or minimize the problem would be to compose your frame then use the focus point selector to place the active focus point on any of the 2 subjects.
 

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Crappy

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Aug 11, 2009
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#15
er... both subjects stand in almost straight line...
photographer parallel with the subects...
select single AF...using either 1 of the subject as the focus point....

tat should keep both in pretty much in close focus if shooting in f2.8...
else...bump up ur aperture to f5.6 then kick in more flash...


*kindly amend me if i'm wrong...
 

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night86mare

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#17
Just curious...will bumping up to f5.6 and more flash helps? U tried it b4?
he probably thinks that you are shooting indoors.

therefore, f/5.6 increases depth of field, so both will be more likely to be in focus at the same time.

flash will be because of lighting limitations, f/5.6 with most handheld speeds indoors will be likely very dark, hence he suggest flash.

how he read your mind, i dunno.
 

Crappy

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#18
Just curious...will bumping up to f5.6 and more flash helps? U tried it b4?
he probably thinks that you are shooting indoors.

therefore, f/5.6 increases depth of field, so both will be more likely to be in focus at the same time.

flash will be because of lighting limitations, f/5.6 with most handheld speeds indoors will be likely very dark, hence he suggest flash.

how he read your mind, i dunno.
lol...1st thing came into my mind for ur question is referring to indoor...

btw..bro night86mare...u can read me...haha..
 

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aspenx

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Aug 10, 2008
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#19
Get a pns with those clever face-detection thinggies.
 

daredevil123

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#20
Just curious...will bumping up to f5.6 and more flash helps? U tried it b4?
I am not sure about other brands of flashes. But for Nikon iTTL, the flash metering is separate from the camera metering system and the flash metering system is actually center weighted. So, you might want to use FV lock for this situation, since your subjects are both off center.

Some good reading material on TTL flash meter:
http://nikonclspracticalguide.blogspot.com/2008/01/ttl-flash-metering-system-not-ttl-bl.html

Good reading on how to use FV lock:
http://nikonclspracticalguide.blogspot.com/2008/01/4-so-what-is-flash-value-lock.html
 

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