@sebfarges Thanks for this Seb. So what's your opinion of the new photo 4K modes with your lenses?

The "AF Tests with the GH4 with Firmware 2.0" video Vitaliy posted above clearly shows that the GH4 is not making use of a fast "Depth From Defocus" AF in video mode - what a pity! I think it would have been the most obvious and useful application of DFD to realize a continous AF in video mode, but for some reason Panasonic never told, that wasn't implemented. As it is as of today, continous AF in video mode stays unuseable for basically any practical purpose.

@Vitaliy_Kiselev: I understand that the continous AF has to use the read out from the sensor, which will only arrive with the same FPS rate used to shoot video. And I could sure use a continous AF that is slower than the single AF for pictures. But the distinguishing feature of DFD would be to not "hunt" into the wrong direction, which causes these awful sequences where the picture becomes very blurry before it gets sharper again. And I am sure that even if it took let's say 1.0s instead of 0.2s to fix focus, this would still be ok if the picture would only get sharper during that period. But without DFD, the camera is changing focus into the wrong direction half of the time, and that is causing sequences you really cannot expect people to tolerate in a final cut.

@Adamt: I think you got me wrong. I don't ask for "super fast AF when shooting video", just for a focusing that does not "hunt into the wrong direction first".

@karl

<hunt into the wrong direction first

You know DFD hunts in the wrong direction first right? It just does it quickly and in small increments so you don't notice it.

The video above is meaningless. The lens has more to do with AF than anything else. In this case the 20mm F1.7 is the limiting factor. It is not capable of fast focusing.

I have tested the 35-100mm F2.8 with the new firmware and it is clearly better in the video/still mode than in true video only mode. It isn't perfect but it is much better.

I hope it's not the new Remote Control (PTP) function that has been added under the "USB Mode" that may possibly affect the " PC connection" connection function.

@mpgxsvcd: In general, "Depth From Defocus" computes the distance of an object from its image, using known blurring properties of the used lens (see this article (paywalled) or this article for more details. BTW: It's interesting to see it took 22 years, from 1992 till 2014, before DFD went from a practical implementation in one camera into the mass market).

Knowing the distance means that the very thing you can avoid is an initial mis-hunt into the wrong direction. What DFD cannot avoid is further small adjustment moves around the initially computed position, but slight variations are not what puts the viewers off - its the long initial "hunt" into the completely wrong direction that looks awful.

Also according to the published properties of DFD in the GH4, the initial movement of the focus plane is precisely what is done "into the right direction", different from when not using DFD.

So I think there is no good known reason why Panasonic could not implement DFD for continous video AF.

I would not be concerned if the "AF Tests with the GH4 with Firmware 2.0" video just showed overshooting the calculated focus position, but it also shows many times that when the person changes head position, the initial big focus movement goes into the wrong direction. And this is an indication of not using DFD at all for video autofocus. Panasonic wrote in their specs that the LX100 does not use DFD for video AF, but I have not seen word on this in the specs of the GH4.

(BTW: The paper from 1992 I linked above says: "DFD1F has been successfully implemented and tested on an actual camera system named SPARCS. SPARCS can determine the distance of an object placed in front of it at any distance in the range of 0.5 m to infinity, and can successfully focus the object by moving the lens with a root-mean-square error of less than 6% in terms of lens position" - that would still today be a huge improvement if available for video AF.)

@tinbeo

I updated mine with that battery. Unlike other Panasonic cameras the 3rd party batteries for the GH4 will show accurate time left.

WOW great footage 'sebfarges ' I installed the 2.0 firmware last night and did some quick afternoon and evening shots. I noticed how bloody sharp and noiseless the footage is, maybe this is due to the Ratios (4x3 and 1.1) being close to the shape of the image sensor??? and not having to much internal fold-down (Folding Down =video Noise) The update didn't work on my Samsung super dooper 64gb SDXC card but worked on a PNY bog standard 32GB SDHC card. Doing some more shooting in Soho, London today while on my late afternoon break from work. Will be using my ISCO anamorphic and my trusty old school Olympus 50mm f1.8, will edit and upload over the week end. So far bloody impressed, well done Panasonic!

@fosterchen the close up on that looks a like 70s B movie! Assault on Precinct 13 !

The 20/1.7 is the absolute worst lens to use for testing video AF. Panasonic doesn't even rate it as certified for C-AF.

@AdamT You make a very good point!

Does anyone have a link to the matrix that shows Panasonic lens capabilities (like which are capable of C-AF)? I seem to remember seeing one, but I can't find it anywhere.