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BillP2R Jun 24, 2007 8:40 AM

I was with one of my Sons at an auto race event yesterday.

He was using his brand new D-80 and I was using a D-80 I've had for about six months.

He asked why his would occasionally run through what seems like the full focus range of the lens before locking focus even though he had just take a picture of another car at the same position on the track.

I told him my D-80 does the same thing, but I didn't know why.

We both find it frustrating that we sometimes miss the shot because the focusing takes longer than usual as it goes through the full range before locking and allowing the shutter to trip.

Anyone have an explanation?

------------------------ Bill

fewpics Jun 28, 2007 2:55 AM

What mode are you using itin e.g Auto, Shutter Priority etc...??? What lens are you using, also...???

What focusing parameter have you set it to - how many focus points - which type of focus are you asking it to perform e.g wide area, dynamic, single etc...

These all affect the way it focuses or tries to focus on an object and I have fallen victim to this in the past by trying to set a too wide focus area and aiming at anobject which had littlecontrast to focus on, especially black... It kept trying to hunt and focus on objects other than the intended subject and I would wave it around until I finally got the subject in view. I have learned how to get around this but for some reason, everytime I change a lens, it loves toset the type of focus to something new, hardly ever the same even if I used the same lens again at some stage. It appears to have a mind of its own... It's not a fault,, more something to do with the firmware and certain default settings I guess...

Try narrowing down the focus area to single area,, or at least pay attention to the focus area. Look at hown many of those little focus icons pop up when you press the shutter button and before it takes the shot. If multiple icons pop up then it may be too many for that type of shot... I am sure its in here your problems starts...

BillP2R Jun 30, 2007 12:18 AM

I was using the 18-135 kit lens (near the 135mm end of it's range when the problem came up) and my son was using a 70-300 VR as well as the 18-135 kit lens.

We were both using the sports preset.

If I remember correctly, my viewfinder usually indicated just the center focus target, occasionally a few (usually 2) more. Don't know what my son was seeing.

With respect to the contrast issue, it was a bright sunlit scene and the race cars would seem to provide good contrast to the track pavement.

What puzzles us is that most of the time there was no problem, but when there was, the lens seemed to search through it's full range of focus before ending right back where it was for the previous exposures and focal length setting.

------------------------ Bill

slapo Aug 8, 2007 3:44 PM

It's possible that the subject was out of the focus a little and the D80 might have gotten confused (or was it the lens, since it's AF-S lens?), not knowing which way to go to focus.
Also, if you have issues like these, you may want to try full manual mode or shutter priority mode, use AF-C and dynamic area AF and keep the shutter half-pressed all the time (if you're pointing on what you want to have in focus, that is).
One trick to try could be zooming in why keeping the shutter half pressed all the time.

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