GH3 GH3 (or GH2) Auto Rack Focus

I

iancarlson3000

Member
I've tested the GH3 ability to auto rack focus. It's pretty good, but it usually goes past my target focal plane and then snaps back into the correct one. I suspect this has to do with the algorithm needing to pass the maximum output of the filtering (i.e., phase change, contrast, etc.) in order to really know it's the best focal plane. Has anyone had a different experience using the auto focus?

I'm thinking it would be an awesome feature for the camera to remember to the focal points the user has selected and then be able to rack between those two points, or between infinity to one of the points, or macro to one of the points. That way, the user sets the marks before recording and then trigger the rack focus while recording. No need for focus puller!

I wish Panasonic would open-source an API for this baby.

Kickstarter?
 
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At the beginning of the video below I did a simple focus pull using the touch screen to refocus from the Ipad to the climber. I thought it worked very well.



All three of these videos are shot entirely with AFC and the 35-100mm F2.8 lens. Check the ending of the 3rd video. It shows the AFC from a very far distance away to almost the minimum focus distance of the 35-100mm @ 100mm. It misses occasionally but I doubt there is anything else that can do it better with the same depth of field.


 
That rack focus in the first video looked solid. I'm not sure what I'm doing differently. In the second shot of the video below is usually how the auto-focus performs for me. Definitely useable, but overshoots a little and snaps back into place.

 
It also depends on the lens used... Some lenses are spot on, some have to search or 'hunt' for a while.
 
Stab said:
It also depends on the lens used... Some lenses are spot on, some have to search or 'hunt' for a while.
Click to expand...

Amen to that. The 35-100mm F2.8 is the only lens I use now for that very reason. Fortunately I almost never need a brighter lens.
 
Fly-catchers said:
Is it as precise on your GH2 as well?
Click to expand...

No. The 35-100mm F2.8 is good on my GH2 but no where near what it is on my GH3. I had the 35-100mm for about 2 months before I got the GH3 and then I had it for another 1-2 months when my first GH3 was being fixed/replaced. Let me just say that I really didn't appreciate the 35-100mm as much with the GH2 as I do with the GH3.

My GH2 just sits in a bag at home as a back up camera. For my needs there is nothing that it does as well as the GH3 can. I will probably sell my GH2 now that the prices are starting to increase for it.
 
iancarlson3000 said:
I've tested the GH3 ability to auto rack focus. It's pretty good, but it usually goes past my target focal plane and then snaps back into the correct one. I suspect this has to do with the algorithm needing to pass the maximum output of the filtering (i.e., phase change, contrast, etc.) in order to really know it's the best focal plane. Has anyone had a different experience using the auto focus?

I'm thinking it would be an awesome feature for the camera to remember to the focal points the user has selected and then be able to rack between those two points, or between infinity to one of the points, or macro to one of the points. That way, the user sets the marks before recording and then trigger the rack focus while recording. No need for focus puller!

I wish Panasonic would open-source an API for this baby.

Kickstarter?
Click to expand...

have you upgraded the firmware. I bought a new 12-35 just over a month a go and it was still version 1.0.
 
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