AF.C focusing, full explanation please

I am a bit curious to know how popular is the AF.C focusing mode amongst our members here and where and when is mostly used.

Can someone please break it down this in details, other than obviously the most obvious which is that it constantly tracks and focuses the subject as long as the shutter release button is half pressed.

As an example here, if the Drive Mode, "Continuous Hi" is chosen in the Fn menu (aka machine gun mode, ok I just made this up), and if you have the focusing mode set for AF.C and shot a subject keeping your shutter release button completely pressed, would the focusing still track the moving subject? Or the moment the shutter release button goes from half pressed to full pressed the focusing locks and all the images under that shot will be taken at the locked focus?

Just curious what members understand from this feature and also reading from the manual please

Yes it would focus during shots as best as it can, the problem is that it can only focus when the mirror is up so when making a photo it isn't focusing.
It needs the mirror because it reflects the light onto the AF sensor.

With the K10D I hardly use AF.C, with moving subjects I predict where it will be and focus there and wait till it's in focus.

i use afc 99% of the time,
helps with the birds,
[IMG]http://i727.photobucket.com/albums/ww272/scottthehat/perigrinefalcon2.jpg[/IMG]

Scott I'm going off topic now but how much do you sharpen your photos, i think you've some halos because of that?
Here is a little trick I used when I get those halos, I duplicate the original layer without the sharpening and place it atop of the sharpened version and set the layer to darken and around 70% opacity, that way it darkens the white halos you get, but you still have the sharpening on the subject.

stefan in all honesty this pic was under exposed, and is heavily croped,

is this the same,[IMG]http://i727.photobucket.com/albums/ww272/scottthehat/perigrinfalcon1.jpg[/IMG]

It's hard to see on this crop but you have a bright line on the birds left wing tip (so his left)
But that can also be aberration, you know for yourself if it it's introduced by the sharpening.

With the first photo you see a bright line along his left flank.

With this shot, you see it alone the outline against the blue sky.

AF-C seems to get quite a few negative comments but I've used it recently for some of the 1st shots taken with my new K20D...all were "motorsport" panning shots and the AF-C seemed to work quite well. I posted one or two of the shots in this thread

https://www.pentaxuser.com/forum/topic/pageant-of-power---cheshire-13528

Simon

Simon those are shot from the side so it's easier for the AF to keep track on that, if something comes towards it would have a much harder time.
These where done with manual focus link
And this weekend I've been to the DTM and also only used MF, still need to process them. Shot 771 photos that day

That mode always makes me laugh... at myself...
When I first started out I read the manual on how AF-C worked and though it was the most magical invention. I mean, how could the camera be smart and fast enough to track a moving object.
Oddly, every time I went out and tried all I got was out of focus subjects with in focus backgrounds.
Finally it was explained to me that it is simply continuous focus and tracks the object in the focus sensor.... it has no way to determine an object is moving laterally and keep focusing on a subject that moves away from the sensor. (definitely one of those whack yourself in the head moments) Now that we have multiple focus sensors perhaps this works better, but I still get a laugh when I turn on that switch.

Still, I have a hard time keeping the subject on the sensor so I tend to get a lot of blurred subject photos. Using auto to make use of all of the focus sensors seemed to make things worse. The camera could not keep track of what I was trying to focus on. One the subject moved off the current sensor, the tree in the background would become very interesting.

The system probably works much better for birds against a plain blue sky. Tracking herd dogs running back and forth in a open field is quite tricky.
Still, got about 30% hit rate with AF-S but upped to about 50% or more with AF-C and center focus. (probably less than 10% with AF-C and auto select)

Sorry for rambling, but just thought some might get a laugh at my "insights"on AF-C.

Did I miss something? The Pentax AF mechanism requires the mirror to be down, not up. Doesn't the mirror stay up in 'machine gun' mode? If so, how can the AF system work?

Actually I've never used this mode so I'm preparing myself to be shot down in flames . . .