[jbinpg]

Exactly. Removing half-press means you do not need to worry about refocus when you press the shutter button.

[IchabodCrane]

I know this customization has many avid admirers here, but I don't understand the preference. The AF1 setting gives you back-button AF, and AF when you press the shutter. Given that I learned ages ago to press the shutter gently rather than with a quick jerk, I don't understand why turning off shutter half-press AF makes sense. You can still use the back button to acquire focus - and the pressing of the shutter button gives you the same effect at the instant before releasing the shutter.

Is it the case that the AF button on its own is somehow more accurate than the half-pressed shutter button? Has anyone tested to confirm that this is so? I'm asking because I don't know, not because I question the use of AF2. Obviously, training yourself to press the AF button every time is a major change in routine that would require practice; literally decades of muscle memory to overcome!

With back-button only focus combined with C-AF, you get the best of both worlds. Releasing the AF button locks focus (for focus and recomposing) while holding it down provides C-AF. There's no way to do both with the shutter button also activating focus. The only thing you don't get is the focus assist light simply because it's inactive in C-AF mode. Make sense?

[ScooterMaxi Jim]

With back-button only focus combined with C-AF, you get the best of both worlds. Releasing the AF button locks focus (for focus and recomposing) while holding it down provides C-AF. There's no way to do both with the shutter button also activating focus. The only thing you don't get is the focus assist light simply because it's inactive in C-AF mode. Make sense?

Got it - that makes great sense, especially if you want to depend on the higher accuracy of the center spot focus option. The focus options on the K-3 are almost too many to keep track of them. I do a lot of MF, even with AF lenses, but I want to get more proficient in more-active situations. What I have found is AF.A is pretty much useless; BBOF gives you the full control.

Playing with it some, I'm not really happy with the ergos for constant AF. Thumb wants to be close to the wheel while AF button is a bit awkward - compared to using it for a quick press. I guess I can get used to it.

[derekkite]

Got it - that makes great sense, especially if you want to depend on the higher accuracy of the center spot focus option. The focus options on the K-3 are almost too many to keep track of them. I do a lot of MF, even with AF lenses, but I want to get more proficient in more-active situations. What I have found is AF.A is pretty much useless; BBOF gives you the full control.

Playing with it some, I'm not really happy with the ergos for constant AF. Thumb wants to be close to the wheel while AF button is a bit awkward - compared to using it for a quick press. I guess I can get used to it.

It took me about a month of shooting for it to become second nature. Now any time I use a body that has half button focus it annoys me.

[Krusty Surfer]

Very interesting! ...in C-AF option your saying you press back focus button and the camera will maintain focus until you depress the shutter?

all on its own?

and to use the 9 or 27 pt array with center priority for most accurate tracking? (like a surfer coming towards you on a wave) auto tracking (or hoping its auto tracking) the surfer coming at you... what will give the highest percentage of keepers?

What Exact settings?

i am about to put the K-3 in a dedicated water housing with flat port 24mm focal length on the lens (18-50 f2.8 sig)

i will not be using the view finder to frame the shot i will be in close quarters

the housing has a pistol grip(one handed operation) two stage trigger- 1/2 depressed activates focus (but your saying after a few seconds with single point AF-C it will stop tracking... that is not good ) and fully depressed takes the shot.

i need the camera to auto track as long as i 1/2 depress that trigger (which is connected by camera trigger cable to camera inside housing)so when i pull that trigger my subject will be in focus please!

Which settings will give me best results? floating around in the water is fun but i need keepers... not just- sometimes a keeper!

All of your Minds Intelligent advice will be greatly appreciated-Timothy