[slip]

K5IIS 5 point autofocus option, what are the advantages/disadvantages of this over the 11 point mode? Are the physical sizes bigger with 5 point?

Any and all opinions welcomed!

Thanks

Randy

[Adam]

I think it's mostly for those who want to shoot moving objects that might not always align perfectly with the center of the frame.

[Na Horuk]

As far as I know, if you have auto points it will very rarely select a point on the side, especially the farthest ones. doubt you would notice a massive difference, its probably just what Adam said, if you use AF to track objects. But I think you would be better off using either centre point or select point (and you just select the point you need). But auto select point isn't terrible, I often use 11 point auto. 5 point just makes sure the ones at the far sides aren't used, in case you know that you definitely don't want the camera to focus there.

Oh and I don't think the size of AF points changes due to settings, the size is a hardware thing so its pretty much set in stone.

[imtheguy]

I have one odd but applicable experience to share. One day on an outing I went to shoot down a fence line in portrait mode by focusing on the tip of the first railing support that was all of 3m away. To my chagrin the combination of portrait plus 5-point with center point only AF could NEVER obtain focus with the K-5. Changed to 11-point and center-point focused fine so I switched back and forth half-dozen times and it was consistent. I have no explanation. Landscape mode did not matter but portrait required 11-point even though it was center-point focus. So I just leave it in 11-point until somebody smarter than me explains it.

[CB Knipp]

I leave my cameras set to select point and almost never switch from the center point. I never use the auto 11 or 5 and therefore do not fully trust that they will focus where needed. Manual focus tends to be the most realiable...

[JimJohnson]

I use selective focus. All the points are available to me, but I, not the camera, chose which one to use. Unless DOF will be an issue when recomposing, and/or the camera is locked down on a tripod and/or it negatively affects exposure metering, I use the center point to focus, set exposure and then recompose.

[snostorm]

Hi slip,

I think that Adam and Na Horuk are closest to the best answer so far. I can't read the minds of the Pentax designers, but I think it would be a pretty good guess to think that the designers included the 5 point Auto option as an expansion of the center point as an active area when shooting AF-C and moving subjects. The central AF area is relatively small (the area of the ( ) marks on the stock focusing screen), shooting moving subjects usually means using a longer lens with a subject that's relatively small in relation to the total area of the scene in the VF, and if the subject is moving, AF needs to be as fast as possible to keep up.

Reducing the AF areas that are considered active by the internal processor of the AF system from 11 to 5 will speed up the relative AF processing. Increasing the AF areas considered by a factor of 5 increases the chance of having a viable contrast border within the active AF areas, and would allow the continuous AF to stay on target if the subject is not kept perfectly centered throughout a series of exposures.

Personally, initially I did not find using 5 point mode much different from 11 point Auto Select, so haven't used it for Birds In Flight shooting, but it's a good idea on paper. Even though I primarily shoot birds, I do very little BIF shooting, and my mastery of the technique of panning accurately with a moving subject is far from the best, so I need all the help that I can get, so I stick with 11 point Auto Select to make up for my deficiencies in this area.

It's just another option that you have at your disposal if you find it useful. I'd suggest that if you shoot moving subjects with AF-C, give it a try. If you find it helpful, then use it despite what others might think of it. In the end, you're the photographer and make the choices.

Scott

[Iksobarg]

Some of the above points helped but I'm still not clear on center-5-11 point AF.

I started with a Kx back in 2011 and graduated to a K30 in 2012. I'm very happy with my Pentaxes so far but the above question has come back to haunt me lately. I recall switching a little between 5, 11 and center point focus in the beginning but since have just left my k30 in center focus and since I was happy with my images the issue never really came up again until lately... as I considered using more than one point but now still wonder, why would I?

Continuous AF I understand completely, no issues there.

I've come to the realization that it was likely in the few times when I used multi (5 or 11) focus points that the pictures were not focused to my liking.

Am I missing anything from sticking to center point?

Does anyone regularly use 5 or 11 point mode?

[JimJohnson]

I typically stick with 11 point for general photography with well defined subjects. When I am shooting in an environment with multiple possible subjects, switch to center focus and/or manual focus. A good but perhaps not obvious example of multiple possible subjects are birds in trees or brush. Twigs or things like the bird's feet on a branch will often grab the attention of the AF engine, when I am more interested in the bird's eye.