Focus hunting on nikon 70-200 2.8?

[nextelbuddy]

i was out yesterday shooting in late afternoon light around 5pm. i started to notice that my 70-200 was focus hunting a lot and it really botherd me to the point where i started manaully focusing.


in this picture the 70-200 would not focus on the purple flower part at all, instead it just continued to just hunt back and forth. (note i was in portrait mode, sometimes when i rotated back o landscape mode it did grab focus a bit better but it definitely hunted in portrait mode more often)

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DSC_9094 by nextelbuddy, on Flickr



i beleive i noticed the lens hard a harder time focusing in bright objects because when i tried focusing on parts of my silver honda fit that were bright and reflective it hunted more than not.


does this sound like normal lens hunting or should i have the lens chcked out?

 

[Temba]

My guess is that if you were only using the very center of the flower & not getting any of the edge then there may not of been enought contrast for the lens to focus on.

 

[trenchmonkey]

Being "inside" MFD will do that too.

 

[VisualEchos]

Yep, I forget that from time to time on any lens, and catch myself starting to rant, only to find out that I'm at or near MFD.

 

[nextelbuddy]

what is MFD? manual focus distance?

 

[VisualEchos]

Minimum focus distance.

 

[nextelbuddy]

Minimum focus distance.

ah so theres a minimum focus distance for autofocus but i would still be able to manually focus?

 

[trenchmonkey]

ah so theres a minimum focus distance for autofocus but i would still be able to manually focus?

If you're inside 4.9' you won't get sharp focusing, neither AF nor MF...it's in the lens design.
I know all my lenses MFD's and mentally just add a foot to that # so I'm never on the "edge" with a money shot. :wink:

 

[fabulas]

Being "inside" MFD will do that too.

X2

 

[Electromen]

On the original 70-200 f/2.8 VR the minimum focus distance for AF is 4.9 ft or 1.5m

 

[Ryan_T]

Being "inside" MFD will do that too.

Price of using an interchangeable lens system. :tongue:

I wonder if a built-in range meter will be built into our camera or lenses someday. Targetting to back/foreground or focus area. Pro body viewfinders will end up looking like tricorders or military helmets. This would cut back on this sort-of issue (that can be eliminated by user practice...really).

 

[gaidin]

I always end up inside MFD with the 70-200 in the studio too...thats usually when I reach for a prime :smile:

 

[nextelbuddy]

i undertand MFD now but what i dont understand is if that was the case then why was i able to manually focus perfectly? i must not have been in MFD then and possibly it was an issue with the lens/camera not being able to focus due to a non contrasty overly bright subject area?

 

[Uncle Pug]

why was i able to manually focus perfectly?

I've noticed I can get a smidge closer with manual focus after the autofocus has reached its MFD. I've noticed this on lenses other than the 70-200 as well.

 

[TomS]

Also remember that the more exacting cross type sensors are closer to the center and not at the viewfinder's extreme edges.