[Mystic]

hi, I'm interested to those who own K-7 or are aware of the technology used to answer my question.

how does the face detection work?

for example, if in a picture there are 5 people and all standing in the same range from the camera.. then it's clear.. it focuses on their faces..
but if there are 6 people and all of them stand in different distances from camera, what does the camera do? closes aperture so all faces would be in focus? or what?

thanks.

[Shashinki]

It usually focuses on the face closest to the camera.

Its a lot faster to just focus normally, so I'm not sure why they even put this feature in.

Catering to the P&S crowd I guess...

[Mystic]

thanks Shashinki,

but it's a little frustrating

[therion]

Maybe, this feature is good just for the Japs, as I have seen them taking pictures of themselves wherever and whenever they could :-)))

[kittykat46]

I always thought of it as a gimmick on P&S cameras - they all seem to have this feature now.
Its weird seeing this feature pop up in a semi-pro dSLR.

From what I see, it works about the same way as the Auto AF point selection logic, except the AF logic is picking up human faces - i.e. roughly oval shape, 2 eyes, 1 mouth. Somebody has obviously worked out the mathematics and software logic to teach the camera processor to "see" a human face.

The "main face" that the AF picks on is likely to be the largest or nearest face appearing in the Liveview scene.

It does sometimes get confused by something else in the scene which may look like a face e.g. a doll, a photograph or painting with people in it etc...

[airconvent]

Face detection arose from the requirement to make sure a group photo is sharp.
I think it does this by identifying faces, then establish their distances from the camera before setting the aperture for the appropriate DOF to keep everyone in focus.
Without this feature, the camera may focus one the face in the centre and making the other faces at various distances out of focus.
Have not really tried this feature on my K7 though.

[AlexL]

From my observations, face detection addresses the issue that most casual P&S users don't even know where or even what autofocus points are. For them, it works great. For the rest of us who are so intimately familiar with our AF points and all the little tricks to make the most of AF that our significant others are jealous, it's absolutely useless.

It's a little bit of a gimmick, I definitely agree, but I also think it's also a creative solution for an audience that you can reasonably guarantee will never pick up the manual.

[kenyee]

Without this feature, the camera may focus one the face in the centre and making the other faces at various distances out of focus.
Have not really tried this feature on my K7 though.

I doubt it'd work that great w/ the narrower DOF of SLRs. It'd have to understand that it has to stop down a lot to get as much DOF as a P&S

[mtroute]

Maybe, this feature is good just for the Japs, as I have seen them taking pictures of themselves wherever and whenever they could :-)))

"Jap" is a derogatory term used by WWII vets and my dad...

[DJEZRAJ]

I agree it is 2009 and "Jap" is no longer OK. So are several other terms. Im sure Therion did not intend it to be derogatory. Im just saying..

[Arpe]

"Jap" is certainly not derogatory in this country, and I am amazed it can be construed as such, it's just short for Japanese, just like Aussie or Brit. PC gone crazy.

Face detection is fun, the first few times, but I'm not really sure what it "does", even though I've read the manual.

[therion]

Ok, I apalogize, I´m not native english speaking.

[AlexL]

Ok, I apalogize, I´m not native english speaking.

You were also not raised in the United States, so no harm done; you did not know and weren't likely to know.

During World War II in the 1940s when the United States was at war with Japan, "Jap" was used a derogatory word towards the Japanese. It was part of viewing them as the "them" in the "us versus them" mentality that often arises in conflict. It's probably still regarded as derogatory since many people from the 1940s are very much alive, both the people who used the term and the people who were on the receiving end of it.

It'll probably just take time with the changing generations for the word to completely lose its punch. For example, in the LGBT community the older generation considers "queer" to be offensive while many in the younger generation does not.

[jptreen]

As for face detection CAF, I've used it a couple of times and it makes me feel a little wierd - DA Ltd lens and the best AF system in a Pentax camera ever and I'm looking at a little orange box trying to work out what I want to look at most.

As said before me - pointless.

[falconeye]

how does the face detection work?

Here are your answers:
- http://www.tessera.com/technologies/imagingandoptics/Documents/Tessera_Face_...te_09.2009.pdf
- http://www.tessera.com/technologies/imagingandoptics/Documents/FotoNationFACETOOLS_web.pdf

Pentax licensed the "FotoNation FaceTools" library and linked it into their firmware. I doubt that any Pentax engineer knows any more details about it.


The ugly part is that we all pay a small license fee for face detection to Tessera in Calif. when buying a dSLR these days ...
(from Tessera's revenue and #cameras sold I would say that the fee is about 1$)