Sony Face Detection, Eye AF and how they work

Discussion in 'Sony Alpha E-Mount Cameras' started by mcvu, Sep 28, 2014.

  1. mcvu

    mcvu TalkEmount Regular

    90
    Sep 24, 2014
    Bay Area, CA
    Minh
    I have A7R and recently got A6000. I have been playing around with the Face Recognition (FR) and Eye AF features and here are what I found. The features work the same on both cameras, tested with FE 35mm f2.8 and FE 55mm f1.8 lenses.

    Eye AF is best for static portraits. It might not work on moving subjects.
    To use Eye AF, assign it to a button, press and hold, a small green square will appear over one eye, then press shutter to take the shot. If you wanted to focus on the other eye, press and hold again.
    Because I take lots of portraits, I assigned Eye AF to AEL button on both cameras.

    If you used wide-open apertures (1.4, 1.8, 2.0, etc), then focusing is critical and Eye AF is a great feature to have. I prefer to use Eye AF over manual focusing, even with the great peak level and magnifier functions.

    1. Eye AF works in all focusing area: Wide, Zone, Center or Flexible Spot.
    2. Eye AF works even if Face Recognition (FR) is OFF and it doesn't matter which Focus Area was selected. As long as you press the assigned Eye AF button, camera will focus on the eye, even if you're using Flexible Spot S and the spot is not anywhere near the eyes. The only difference when FR is ON is that the camera will auto-adjust exposure for the face. If FR is OFF, no priority is given to face exposure.
    3. Eye AF works well with FR ON.
    4. FR will also work in all Focus Area mode, as long as the face detecting square touched any area of the selected focus area. When FR is ON, camera displays a square over the face. If the square border is gray, i.e. it doesn't touch focus area, then when you press to focus, it will not focus on the face. If the square border is white, ie. it touches focus area, then it will focus on the face. If you used Wide focus area, then the square should always be white because most of the screen is covered by focusing points.

    Items 1 & 2 are the surprise discoveries for me because all Internet reviews & recommendations I've found so far indicated that Wide & FR are required for Eye AF to work.
    Updated: Regarding item #2, it might be true that even if FR is OFF, the camera still has to be able to detect a face in order for Eye AF to work. It just doesn't show the face detection square if FR is OFF.

    It seems face detection usually focuses on the eye and we don't need to use Eye AF button. One way to check that is to set focus mode to DMF, turn on Peak level, then use face detection focusing and look for the Peak highlights. They are usually dead on the eye.

    Any other suggestion and recommendation are always welcome.
     
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  2. davect01

    davect01 Super Moderator

    Aug 20, 2011
    Fountain Hills, AZ
    Dave
    It is quite fascinating that a camera can know what an eye is and take advantage of it.

    Neat stuff.
     
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  3. ferrellmc

    ferrellmc New to TalkEmount

    7
    Jul 30, 2014
    Maryland
    Excellent post and a good reminder to use Eye AF. I use Flexible Spot small and I wonder how it compares to Eye AF in terms of accuracy in locking on, speed of locking on and low light locking on. Eye AF has the little square, similar to the superb focusing of the A6000, hmmm any shared technology?
     
  4. mcvu

    mcvu TalkEmount Regular

    90
    Sep 24, 2014
    Bay Area, CA
    Minh
    In most scenarios where camera can detect face & eyes, Eye AF is as fast as Flexible Spot (FS). In other situations, it might be a little slower. But the trade off of not having to manually move focusing point around or focus & recompose is huge. Especially when you keep moving around and take fast, multiple shots, both portrait and landscape, to get different angles, Eye AF (or Face Recognition) beats other focusing modes handily.

    Because Eye AF uses a smaller focusing region, almost 4 times smaller than Flexible Spot small, it usually is more accurate; whereas FS might focus on hair next to eye.
     
  5. Rollin

    Rollin TalkEmount Regular

    97
    Jul 2, 2014
    Cedar Rapids, Iowa
    Pls post if you find any other insights if Face recognition is hitting the eye all the time and Eye-AF is redundant.
     
  6. LoFi

    LoFi TalkEmount Regular

    101
    Nov 16, 2013
    Eliot
    i wish you could eye af with the wifi app
     
  7. Jefenator

    Jefenator TalkEmount Top Veteran

    876
    Nov 23, 2012
    Oregon, USA
    Jeff
    Point #4 is good to know - thanks for sharing!

    One of my intended uses for the AF system is when I hand my camera to a friend for what I call a "third party selfie". Needless to say, manual focus never worked very well (even with some serious photographer buddies who use only DSLRs). I'm very partial to the flexible spot, but it sounds like the wide zone will be preferable for laymen. (Wish there was an extra memory setting handy for that...)

    This tech has already bagged me some real keepers, but it seems a long way from foolproof. But I'm just starting to get a feel for how this whole system really behaves. (The more I learn, the better the "keeper" ratio... hopefully.)
     
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  8. alaios

    alaios TalkEmount All-Pro

    Jan 11, 2013
    Düsseldorf
    Alex
    I never used eye focus and thanks for clarifying that you need to assign it on a button to work.
    What happens in cases though you want to have focus on the eye that is closer to the camera and you find focus to be on the other side of the face? Is it possible to swap?
    Regards
    Alex
     
  9. WestOkid

    WestOkid TalkEmount All-Pro

    Jan 25, 2014
    New Jersey, USA
    Gary
    On my A7 the eye AF button was assigned to the center button by default. I just tried switching. It seems that a slight shift towards the eye you want and another press will cause the camera to focus on the other eye. I'm not sure how consistent it is since it was a quick experiment.
     
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  10. oopsydaisy

    oopsydaisy TalkEmount Rookie

    24
    Dec 26, 2014
    I need to try this on my next shoot. I've been using back button focus with flexible spot small or manual focus. I never thought it would be accurate, so never tried it.
     
  11. alaios

    alaios TalkEmount All-Pro

    Jan 11, 2013
    Düsseldorf
    Alex
    I would like to see some accuracy tests. I guess the most extreme would be to try the eye-focus in cases where the depth of field is really tiny.. just 5 centimeters or even less. That would give us a very good indicator how good it can be.
    The harder for me currently is to find a subject that wants to post for such a test... otherwise the next solution would be trying selfish through remote mode(... but this looks not very easy for me)
    Alex
     
  12. Jefenator

    Jefenator TalkEmount Top Veteran

    876
    Nov 23, 2012
    Oregon, USA
    Jeff
    I'm having some luck, so far. Alas, much of my usage is in conditions where the face-detect and even the AF are strained. That's where the flexible spot AF point serves me well. When face-detect fails, at least I have the AF working on the right general area. When light is better and face-detect is more solid, it's also a good way to ensure that the camera will focus on the face you want (haven't delved into assigning priorities yet...)

    Thus far my "keeper" rate in rotten light seems somewhat better than my older APS-C mirrorless cameras but perhaps not quite as good as I can achieve with a manual lens. OTOH the autofocus allows me to shoot one-handed, use otherwise awkward high & low camera angles and grab shots very quickly as I'm really supposed to be performing music onstage.

    craig-1.

    Hint: the camera's face-detect will pick up images on your TV or computer screen. That's a good way to get a feel for how it works without having to inconvenience a friend.;)

    I'm still not sure how much the "Eye AF" feature will factor in to my shooting. Maybe some day when I have a willing subject close up in better light. I have it assigned to the "AE Lock" button (which makes sense to me, since that button is extremely handy and I probably won't be switching it over to AF/MF whilst planning to attempt Eye AF).
     
    Last edited: Apr 22, 2015
  13. devorama

    devorama New to TalkEmount

    6
    Jun 5, 2015
    Chicago, IL
    I've found that the tiny green square that shows around the eye does not indicate the actual focus area. In reality, it is larger. I tested this on my A7. Using the Eye AF, the focus was consistently on the frame of my glasses instead of my eye. I was able to focus on my actual eye instead of the frame of my glasses by using the small flexible spot. So for extreme close ups of people with glasses, I wouldn't rely on the Eye AF.
     
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  14. unlo

    unlo Sony ******

    Jan 19, 2014
    Ohio
    Matt
    I'm running into a little bit of confusion. Maybe someone can chime in. I'm trying to get lock on EYE AF to work with my a7ii and SEL 35f18. I made the mistake of taking to youtube for help, which only left me more confused than before. So i've seen a video of a7 series camera performing lock on EYE af. yet i can't make it happen on my camera. updated to ver2.0. i can get EYE AF to work using the default center button. but only in AF-S if i turn on AF-C a msg is displayed when pressing EYE AF button that it's unavailable with AF-C ..... i rarely have an AF lens attached to my a7ii this is all hypothetical testing for when/if i get a FE lens in the future. any help would be greatly appreciated.
     
  15. devorama

    devorama New to TalkEmount

    6
    Jun 5, 2015
    Chicago, IL
    Unfortunately, that's how it works on the A7II. The A7RII will do Eye AF in AF-C, but on the A7II it is limited to AF-S only.
     
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  16. dbmiller

    dbmiller TalkEmount Top Veteran

    778
    Mar 2, 2012
    New England
    Yep, the A7ii is like the A6000 and all the older E-mount cameras - They can only do Eye-AF in single-shot (AF-S) mode. The A7Rii was the first to introduce continuous Eye-AF.
     
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  17. unlo

    unlo Sony ******

    Jan 19, 2014
    Ohio
    Matt
    These jerks.... (sony)
     
  18. NickCyprus

    NickCyprus Super Moderator

    Oct 11, 2012
    Cyprus
    Nick
    Haven't played with Eye AF before but I would be very curious to try it and see how it performs on a wedding photography. This is a very useful thread!!! All the other info I've read on the net or seen on YouTube are rather innacurate and/or confusing...Until now my default setting was flexible spot Large but without a dedicated joystick its not rather fast or convinient
     
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  19. WestOkid

    WestOkid TalkEmount All-Pro

    Jan 25, 2014
    New Jersey, USA
    Gary
    The eye AF on the original A7 isn't that useful since it doesn't have tracking like the eye AF on the A7RII. You basically need a static subject and good lighting, both requirements are not ideal for wedding photography. It's also not automatic. You have to press and hold an assigned button with 1 finger and the shutter with the other.
     
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