Focus tracking

Started 1 month ago | Questions thread
OP DavidWright2010 Senior Member • Posts: 1,739
Re: the transom window test

flektogon wrote:

KPM2 wrote:

Hello

I had a K5 and went to a KP and K1. The SelS, SelM SelL I didn't had on my K5, also the hold time setting was new for me.

Well, I can't find any reference to SelS, SelM SelL in the KP operational manual.

I have the same problem. What are these?

Before I made endless out of focus BIF pictures, I did try out the behaviour of this new to me AF fields and hold time. Instead of using a moving object, like a bird, I used a static object and moves myself. My object was a transom window. Before I go on, I will mention this: we give the OP our tips what will do work, but we must count in that we use sometimes other cameras like the OP. The K70 has a SelEX, where it use 11 AF points. When I for example use the 25 AF points with my KP, I use than a similar AF-frame area size as a K 70, but my 9 AF point frame area size is much smaller than the 11 AF point frame area size of the K 70.

Basically what you want to say is to use as large frame area (which contains the AF points) as possible.

Only a restart (=stop pressing the shutter release button and hold it down again) of the AF can bring me back to the sash bar.

But only if you pre-set (manually) your lens to focus on that closer area. If the camera's AF system is happy with the sharpness of the immediately projected image, it won't bother to look for another (even if it was a closer) area.

When I use the SelM, it's clear that, because the 25 AF point frame area size is bigger, I lost my focus on the sash bar not so quickly when I swing to the left and right, but when I lost it, the advantage of using the 25 AF points invert there using like the 9 AF points, too, because the camera use than 25 AF points for to be able to stay on the tree.

SelM ?

When I use only one AF point, it's clear that when I swing to the left and right, that my KP do focus at once always to the object, my AF cover, so it focus to the sash bar or the tree or back to the sash bar. And this can be a goody of using only one AF point, when I can bring back my AF point to the object, my camera do focus again on it. A restart is not needed.

What do the hold time setting ?

Try it out with our own camera. I tried it out with my KP in AF-C, single AF point and when I swing to the left and right, my KP hold the focus on the sash bar, depending on my time setting, short, middle or long, before it focus to the region, where my AF point was. Now on that way I lost my sash bar not so quickly when I swing to the left or right, but when it did happens that my KP focus to the tree, it's clear that it also did wait as long for to focus back on my sash bar. So when I use a hold setting and a single AF point, I must be aware that when I lose the focus on my object, and the camera focus to an other one, I can held back my focus point to my object, but the hold time prevented that my camera focus at once to it. So, when you use a long or middle hole time, it's better to restart the focus than.

can the hold time cause other not wonted behaviours too ?

Yes it can. For that I move now back and forth. Camera in AF-C, single AF point.

hold time is off:

My KP focus continually on the sash bar during my movement:

but now I use hold long and with the same movement my KP did used the hold time, so that it show me that for a while until it start to focus again:

That the camera interpret a moving to a hold time needed moment, depends to my mind on how contrasty my object is. The sash bar has a bad contrast, but when I use a object with a good contrast, my KP do not interpret my moving to a hold time needed moment, it do continually focus on my object than.

So, when I use the hold time, I try to be sure that my object has a good contrast, else, I use no hold time.

BTW: I take during this tests no pictures, I only watch what my camera do. The pictures I made only for to show what I see than.

best regards KPM2

Yes, I agree with all what you wrote and demonstrated, just those SelX terms are mystery for me.

So, ignoring the fact I don't know what SelM is, thank you for this extensive discussion, but it seems to me that you are using what you see in the viewfinder as what you use to determine focus. That is not nearly good enough to judge best focus, for me at least. And if you are talking live view, my lens is very marginal about AF in live view, often failing.

David

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