[charliezap]

I'm using my K5IIs camera with the Pentax 300mm DA lens. What focus settings should I be using when trying to catch a bird on the wing with a minimum of "focus hunting"--charliezap.

[kypfer]

I'm using my K5IIs camera with the Pentax 300mm DA lens. What focus settings should I be using when trying to catch a bird on the wing with a minimum of "focus hunting"--charliezap.

Focus settings : centre-spot AFC … keep "half an eye" on the Green Hexagon focus confirmation indicator at the bottom of the viewfinder. When it's lit you're good to go. The red light that comes on only indicates which focus point is being used, not that a lock has been achieved.
Camera settings : as close as possible
Seriously, the closer you can get to your subject the bigger it will be in the viewfinder and the less problem the camera will have in concentrating on the one subject without getting "distracted" by a cluttered background.
Don't bother with multi-point focussing unless it's against a clear sky.
Some will recommend using "back button focussing" … look it up if you're not familiar with the term. Personally, I rely on a half-press of the shutter button, but it's a person-by-person choice.
Practice your panning technique, even if it's only on the local pigeons or gulls. You need to keep the subject centred in the viewfinder for the autofocus to have a decent chance of "locking on".
Depending on your lens' ergonomics and your personal preference, getting the subject "more or less" in focus manually before activating the camera should help the camera to "get it right" first time.
Good luck

[K2 to K50]

I find centre spot focus a real challenge with bird-in-filght, especially with my main lens, the very heavy 150-450mm.
So I have reverted to zone-select medium. AF-C.
And, with the huge 150-450mm, continuous shooting (medium or high).
And finally, a shutter speed of 1/2000th. If your tracking skills are better than mine, you might be able to get away with a slower shutter speed.
I presume the 300mm will make tracking easier.

Here is a recent shot of mine that I was pleased with using my 55-300mm PLM lens:

Long-billed Corella in Flight - PentaxForums.com
And one with the 150-450mm monster (note the higher shutter speed!)
Pied Cormorant - on Landing Approach - PentaxForums.com.

Generally, unless you are up very close and personal, you don't need to shut down for depth of field, because of the distance between you and the subject, so you can stay fairly wide open with the aperture, and go for shutter speed.

I have saved my preferred settings to one of my custom User settings.

The 150-450mm zoom has 3 distance settings to minimise auto-focus time and hunting: near distance (2-6 metres), full range, and a 6 metres to inifinity. I don't know if your 300mm lens has any equivalent.

[tduell]

I'm using my K5IIs camera with the Pentax 300mm DA lens. What focus settings should I be using when trying to catch a bird on the wing with a minimum of "focus hunting"--charliezap.

I use the DA* 300, and slow-ish focus and occasional hunting was often the case when shooting with my K-3 II.
One technique I have adopted is to always have the focus at infinity between subjects/shots, using the quick shift.
When shooting birds they tend to be at distances of 10m or more, and with the lens at inf. it takes considerably less time to get to focus if starting from inf.
On the K-3 II that didn't always help with focus hunting, but I think it did improve.
I've found that the DA* 300 on the K-3 Mark III focuses much quicker with very little hunting.
Not a complete answer to your question, but may help.

Cheers,
Terry

[rogerstg]

What focus settings should I be using when trying to catch a bird on the wing with a minimum of "focus hunting"

It's not as much a setting as it is a technique. I find it useful to prefocus the lens at a similar range to the intended subject. Something high contrast. It helps the system for focus to start closer to the subject distance. It can be frustrating if starting from close focus, to hear the lens speed past focus to infinity, and then speed back again. edit - having re-read replies, it's fundamentally the same idea that Terry explained. Basically, help your system to help you.

Related is target acquisition, which can be tricky with a long lens. I've started training myself to shoot with both eyes open, right eye on the viewfinder and left eye unobstructed. It takes some concentration, but the results for me are that I find targets much quicker than with one view blocked. I'm sure it helps that I'm usually right eye dominant and a passable wing shooter.

[Kerrowdown]

How to minimise focus hunting

Is to manual focus the correct answer?

[photogem]

Some will recommend using "back button focussing" … look it up if you're not familiar with the term. Personally, I rely on a half-press of the shutter button, but it's a person-by-person choice

I use "back-button-focus" on most of my Pentax DSLR but then set to AF-C. As soon as I let go of the "back-button*", AF-C is no longer active, focus is locked. This works fine if objects are not moving fast.

So often I find it (very) useful but not always.
*AF for the K5II
AF/AE-L for the KP and some others