"catch in focus"

what does this do and does anyone use it.

Focus Trap is a useful tool for some sports events, leave the camera body on AF and with a manual lens pre focus on a point and hold the shutter release down. When the subject comes into focus the shutter fires. That is the theory, but with my Ist D the light and subject contrast has to be good......John

This is what Hardgravity said in the "manual focus" thread:
"You could set catch in focus in the menu to on, then just by slowly focusing through the desired object the camera takes the shot at the optimum moment."
i've looked in the Menu's on both K10 and K100 and can't find reference to it.

You won't find any reference, in the K10D menu's. But it works as described above.
1# set focus lever on af- S
2# focus slight behind or in front of desired focus point.
3# press shutter release button all the way.
4# very slowly turn focus ring until shutter releases.
Or with a moving subject, pre focus on a guessed distance and wait until the subject run's into the trap.

Good luck, it will always be a bit hit and miss.

Martin.

ok cheers guys, the k200 has it, not used it but might muck about with it.

Good luck, I've used it on several occasions with good results.

When using it keep an eye on your focus indicators, the red square in the centre and green hexagon below don't always agree! but the shots still work.

Oh and scottthehat , could you fill in your location please?

The red square shows only which focus point is being used and manual lenses will use only the centre one.

The green hexagon is the only true indication that accurate focus has been achieved.

EDIT: There is also an accompanying beep if you have it turned on. I don't, so I forgot about it as an alternative confirmation.

Thanks Mannesty,I'd forgotten about that.

Ahaaaa! ... so, i have manual focus 50mm prime and a manual 28-70mm, using both for portrait stuff. The theory here is that by setting up on 'c.i.f', i can stop worrying (too much) about whether i'm in focus or not! yay! ... completely missed that i could use it for that! Excellent.

Cant do this, I misunderstand sth
camera body af-s ?
I prefocus manualy.....
when I press the shutter release - it just makes pic as usually - it focuses where the red dot is.....

I do not understand anything

or is it just that i have to hear and notice, when object reaches the point and then press the shutter release

Focus trap only works with manual-focus lenses, not auto-focus lenses.

Camera body is set to AF.
A manual lens is fitted.
The shutter will now only fire when the green hexagon is lit to signify the lens is in focus (centre spot only)
Now, point the camera at a subject moving towards or away from you and pres the shutter release and hold it down. If and when the subject moves into focus, the shutter will fire.
This means you can pre-focus on a particular spot and press the shutter release and just wait for the subject to move into place. When it does, the camera fires the shutter.

So, I can't do that ?


Even if I switch the lense (pentax Da* 16-50) to MF. And body to AF. It shoots anyway, even when it is not in focus (the greeen hexagon is not on)

Anyway, this was very interesting to hear about such possibility.

Thanks for being patient with me

It has to be a manual focus lens, perhaps an AF lens that can be set to MF won't work?

A Pentax A series lens would be perfect for this technique.

Hi John,

Like many I have a bag of MF lenses, but for those that don't, would it be possible for someone with only AF lenses to tape up one or more of the lens/body contacts to achieve the same result, and if so which ones?

Just a thought..

Cheers

Liam