Beginner How does face detection work?

mickledore

mickledore

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I don't do portraits at all, and try and avoid getting a person in my shots other than for use as a prop or for scale.
I never go in the People section on here. (I've got a voluntary ban from there!)
Yesterday a good mate of mine rang and asked me to take some location shots of him for use in the upcoming local elections when he is standing for councillor.
Waaaaay out of my depth, but I owe him a few favours so I agreed. 15 minutes notice!
It was a nice bright day so that helped. I remembered face detection and switched it on.
Fuji X-T2 is the camera.
But it hardly worked. Why? I was using single point focus, and even placing that over his face seldom caused face detection to lock on. I took about 40 shots and maybe half of them showed that face detection worked. The other half relied on routine AF, with focus/recompose used.

So how does face detection work? I thought it was pretty foolproof - I'm the fool in this instance! What else do I need to do to get it to have an effect? I suspect that I will be called out again for similar exercises. Is it a serious tool or just a gimmick to capture the "shots of my kids" market? Does it only work for close in shots rather than wider location shots with a concerned candidate looking worried type shot?

Anyone able to help a complete numpty in this?
 
Face detection works by looking for something the computer recognises as a face in the frame, then focussing on it.

It’s designed for your auntie Mary who wouldn’t understand that sentence.

You’re a photographer, and you know how to achieve focus, and what your subject is. Face detection wasn’t designed for you, it was designed for your auntie who will post all her pics to FB and won’t even notice that some are in focus and others slightly off, and will even post the ones completely OoF.

If you’d have not panicked, and transferred your own knowledge and skill, you’d have done a better job than you did choosing a mode you don’t understand simply because the subject matter seemed ‘different’ to your usual.
 
Thank you. An excellent answer.
Yes I panicked. 15 minutes notice to do something completely out of my comfort zone.

I did notice that the shots I focused myself looked no worse that the face detection ones.

So in future I'll leave it switched off. As you say I can take a shot of any object so won't bother with artificial aids.

Thank you.
 
I too have found the X-T2 face detection very erratic, Frank.

I see many posts about how awesome the Sony face/eye detection is so have been trying it out on my son too but to no avail (I tried it in Zone focusing mode too).

Has anyone successfully used it or as Phil suggests, is it a feature better just ignored for those who know how to focus where they want to generally anyway?
 
Ignore it! It’s [emoji90]
 
Phil V said:
You’re a photographer, and you know how to achieve focus, and what your subject is. Face detection wasn’t designed for you, it was designed for your auntie who will post all her pics to FB and won’t even notice that some are in focus and others slightly off, and will even post the ones completely OoF.
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Totally agree, Phil.

Though I sometimes wonder why Sony decided to include face detection in the A9. I guess it's probably for when you give it to your auntie to use. Either that or it cuts their costs having the same functionality in all the cameras, since it's just software.
 
Funny enough face detection on my phone was accurately acquiring and tracking a Snooker players face on TV.

Not sure how it works but it works it out by the digital data it is receiving I guess.
 
Thanks Ian.
With my complete lack of experience of shooting faces I thought this was the way to go. As Phil says both you and I know how to focus a camera. We would both have no hesitation in getting our own focus on a statue so why do we need to add an extra layer for living people?

I've also found out that face detection alters other parameters as well. It has it's own metering mode that cannot be amended. Spot, centre weighted and average metering are not available. The camera is always using a special version of multi metering.

AF lock is not available when FD is active.

AF-C mode does not work well, if at all.

If FD does not lock on then the camera reverts to previous AF mode and metering reverts to multi metering.

All in all it seems just too much trouble. Fine for the aforementioned Aunt Mary, and her Twitbook shots, but I suspect you are well above that level.
 
It sort of works as a camera trap - when it sees what it thinks is a face, it fires. Not as good as a tool for photographers as it might be for Auntie Mary.

Frank, chances are that a mate of your age will be as craggy as many landscapes!!! :p:p:p:D
 
StewartR said:
Totally agree, Phil.

Though I sometimes wonder why Sony decided to include face detection in the A9. I guess it's probably for when you give it to your auntie to use. Either that or it cuts their costs having the same functionality in all the cameras, since it's just software.
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Because its a very strong tool to have at your disposal.
With the Sony A9 you can pre-program faces into, so for weddings you can set it so it prioritizes on who it focuses on first etc.
Eye-AF is a real game changer and a step forward for portrait based photography.
I wouldn't ever consider buying a system without these features.

Mark twiglet said:
Ignore it! It’s [emoji90]
Click to expand...

I agree, the Fuji XT-2 implementation of face and eye detect are [emoji90]
 
Nod said:
It sort of works as a camera trap - when it sees what it thinks is a face, it fires. Not as good as a tool for photographers as it might be for Auntie Mary.

Frank, chances are that a mate of your age will be as craggy as many landscapes!!! :p:p:p:D
Click to expand...
Hey Nod, it was my birthday last Thursday. At my age there aren't many mates still above ground!
 
He wasn’t taking selfies again was he
 
If it also detects a blue and/or a purple and yellow rosette it converts to a tazer
 
Riz_Guru said:
Because its a very strong tool to have at your disposal.
With the Sony A9 you can pre-program faces into, so for weddings you can set it so it prioritizes on who it focuses on first etc.
Eye-AF is a real game changer and a step forward for portrait based photography.
I wouldn't ever consider buying a system without these features.

I agree, the Fuji XT-2 implementation of face and eye detect are [emoji90]
Click to expand...

Agree Riz (y) Some right stickinthemuds here, can't see beyond the ends of their noses :D

Face recognition might not sound like such a big deal, and it's not in its most basic form, but it's the same technology as subject recognition in general and all that goes with it. It's mainly useful for tracking moving subjects, where the AF will automatically follow whatever you've told it to (by clicking on it) far better than you can by manually trying to chase them around with the AF point. And Sony's Eye-AF is indeed something of a game changer, to use that corny phrase, for anyone who's tried to shoot a portrait at f/1.4 when even the slightest movement of either the subject or camera will demand a refocus. It dramatically improves your hit-rate and makes the whole process flow. Fantastic feature, and one where mirrorless will likely show a real advantage over DSLRs.
 
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