Face Detection, how does it work?


sephiroth

New Member
Jul 12, 2010
27
0
0
#1
Hi everyone,

I have an E-PL2 and one of its functions is face detection. I understand that when face detection is turned on, the camera will automatically try to adjust focus and exposure to the face.

Lets say Ive set my camera to use the center AF spot, and face detection is on. Using my center AF, I half pressed my shutter and locked focus, but the focus is slightly off (slightly front or back focusing), in that case does face detection function automatically compensate and adjust focus to lock onto the face?

Reason for asking this is because, when face detection is on, I can see the big white boxes on each person's face. Am I supposed to shift my center AF to be inside the face detection box, lock focus, then recompose? If thats the case, then whats the difference between turning off or turning on the face detection, since locking focus on face, then recompose, is the norm for taking portraits?

Or can I just compose and press my shutter without locking onto the face, will the camera's face detection function auto adjust my focus accordingly to lock to the face?

Hope someone can enlighten me about how this function work. Thanks alot :)
 

kei1309

Senior Member
Apr 12, 2010
7,312
23
0
Earth
www.facebook.com
#2
i doubt Face Detection works on focusing for the face. reason is, if you're shooting people who're staggered, the camera's gonna have a headache selecting which face to focus on.

rather, i believe it's to correct the white balance, exposure of the frame to ensure that the people are exposed and colored properly.

but that's for Sony cameras ;)
 

Edwin Francis

Senior Member
Mar 24, 2006
880
3
18
www.sgwriter.com
#3
On my old Fuji F31d, face detection tried to focus and expose for the face, no matter where it was in the frame. No need to focus and recompose.
I doubt if any manufacturer would require that -- it is after all supposed to be a feature to attract the casual user, most of whom have no idea what focus-and-recompose is.

For Olympus:
http://www.olympusamerica.com/oai_HeadlinesDetails.asp?pressNo=818

Face Detection with Eye Detect - an amazing new function makes it easier to capture the spirit of your subject, automatically making a person’s eye the focus point of the image. The E-PL2 further reduces the chance of blurred subjects in images by recognizing up to eight faces, tracking them within the image area, and automatically focusing and optimizing exposure for sharp portraits.


Hi everyone,
Am I supposed to shift my center AF to be inside the face detection box, lock focus, then recompose? If thats the case, then whats the difference between turning off or turning on the face detection, since locking focus on face, then recompose, is the norm for taking portraits?

Or can I just compose and press my shutter without locking onto the face, will the camera's face detection function auto adjust my focus accordingly to lock to the face?
 

Rashkae

Senior Member
Nov 28, 2005
19,105
12
0
#4
i doubt Face Detection works on focusing for the face. reason is, if you're shooting people who're staggered, the camera's gonna have a headache selecting which face to focus on.

rather, i believe it's to correct the white balance, exposure of the frame to ensure that the people are exposed and colored properly.

but that's for Sony cameras ;)
It corrects white balance and exposure, but also sets AF if you have the wide-area AF selected.
 

kei1309

Senior Member
Apr 12, 2010
7,312
23
0
Earth
www.facebook.com
#5
It corrects white balance and exposure, but also sets AF if you have the wide-area AF selected.
thanks for the clarification. so i suppose if there's another face behind the actual subject's face, it'll take the nearest face as reference?
 

Rashkae

Senior Member
Nov 28, 2005
19,105
12
0
#6
thanks for the clarification. so i suppose if there's another face behind the actual subject's face, it'll take the nearest face as reference?
If you are in auto, it will adjust aperture to get enough DOF too. ;)
 

limexd

New Member
Dec 14, 2010
109
0
0
Singapore, Singapore, Singapor
#8
Hi everyone,

I have an E-PL2 and one of its functions is face detection. I understand that when face detection is turned on, the camera will automatically try to adjust focus and exposure to the face.

Lets say Ive set my camera to use the center AF spot, and face detection is on. Using my center AF, I half pressed my shutter and locked focus, but the focus is slightly off (slightly front or back focusing), in that case does face detection function automatically compensate and adjust focus to lock onto the face?

Reason for asking this is because, when face detection is on, I can see the big white boxes on each person's face. Am I supposed to shift my center AF to be inside the face detection box, lock focus, then recompose? If thats the case, then whats the difference between turning off or turning on the face detection, since locking focus on face, then recompose, is the norm for taking portraits?

Or can I just compose and press my shutter without locking onto the face, will the camera's face detection function auto adjust my focus accordingly to lock to the face?

Hope someone can enlighten me about how this function work. Thanks alot :)
face detection is more useful if you use a multipoint/wide AF system instead of centre point... allows camera to decide where to focus on

otherwise if you are using centre point AF, point at the face, focus , than compose... most PnS/ and µ4/3 cameras work that way anyway...
 

Octarine

Moderator
Staff member
Jan 3, 2008
12,491
26
48
Pasir Ris
#9
Has anybody tried face recognition on a basket of eggs? :bsmilie:
 

Cowseye

Senior Member
Mar 7, 2010
3,786
0
0
Singapore
www.ttlo-cowseye.com
#10
My "when in doubt" fast solution, set shutter speed to 1/60, set to the smallest aperture possible with sufficient exposure.

If you have tripod, use A mode, set aperture to F/11, remote or timer trigger.
 

Top Bottom