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Old Jun 10, 2008, 3:33 AM   #1
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Just got a Rebel XTi and noticed that on people photos, if I take photos of just 1 subject, my focus is spot on - using center focus.

But when I take photos of groups of people, many times the features of the faces are very soft, even out of focus either on average or center focus setting.

I am using a 28-135mm Canon EF lens USM IS.

Could I request for some pointers on what to watch out for?

Could my problem be with the camera or the lens?

Thanks a lot from a newbie.
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Old Jun 10, 2008, 5:43 AM   #2
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The Depht Of Field depends on the focal lenght and the aperture:
http://www.dofmaster.com/dofjs.html

So if you shoot @ 135mm @ max aperture (f/5.6) the DOF will be less than @ 28mm
-> Increasing the aperture (i.e. close it down will will bring more people in focus for group shot) - I'll use the Av mode to have control over the aperture...
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Old Jun 10, 2008, 10:14 PM   #3
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NHL,

Thanks a lot. The DOF Calculator makes me understand this concept better.

Another question: my 400D has a choice of focus points - either the center or 9 points arranged in an oval pattern on the viewfinder. What is best to use for shots of a group of people?

Thanks.
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Old Jun 11, 2008, 6:34 AM   #4
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I always use the center AF point...

It's more precise (may be not for this lens) but the center AF point is designed for larger f/2.8 lenses for exactly the same reason: i.e. shallow DOF
-> Selecting the correct aperture will take care of the rest - It all depends on how selective you want the background to be included in your picture...
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