GH5 Vrey good comparison of 2.0 Autofocus vs 1.0 autofocus - yes its noticeably improved

looks Panasonic is just falling down here compared to Sony and Canon with video autofocus on the GH5. Is it the large chip as my PX270 has great autofocus. Maybe they should call up the gang over in the broadcast division to check it out.
 
Since a smaller sensor (like the 1/3" sensor in the PX270) has a much greater depth of field, a lot more of the frame is likely to be in focus at any one time. An HD camera like the PX270 also has a lot less resolution (about 2 million pixels compared to 20 million for the GH5) which further reduces the demands on the autofocus system.

I believe most small sensor camcorders like the PX270 just use contrast detection autofocus, which is the same autofocus approach the GH5 uses. It's possible the GH5 autofocus system may actually be more advanced than the one in the PX270 since it is a few years newer. But even though contrast detection autofocus seemed to work ok for small sensor HD cameras, it just doesn't seem to hold up as well for larger sensor 4K cameras.

There are many large sensor 4K video cameras that rely exclusively on contrast detection autofocus, including cameras with 1-inch sensors like the Panasonic UX180, Sony PXW-X70, Sony PXW-Z150; 4/3-inch sensors like in the Panasonic DVX200 or GH5; Super 35 sensors like in the Sony FS5, FS7; full frame sensors like in the Sony A7S, and A7S II. And I'm not sure any of these cameras are seen to have excellent autofocus systems.

Most of the large sensor 4K cameras that have better video autofocus include some sort of phase detection autofocus system, like the Canon Dual Pixel autofocus (in the C100 mkII, C200, C300 mkII and various Canon DSLRs) or on-sensor phase detection with a lot of phase detection points, such as in the Sony a6300 and a6500. And perhaps it's not a surprise that at IBC, both Canon and Sony introduced new 1-inch sensor camcorders with their respective autofocus systems (the Canon XF400/XF405 and Sony PXW-Z90 and HXR-NX80).

Interestingly, the Olympus OM-D E-M1 Mark II (which has a very similar sensor to the GH5) has support for on-sensor phase detection, but it seems that the phase detection autofocus system is not used for video, where it reverts back to contrast detection. And so far Panasonic seems to have focused on improving their contrast detection system rather than adding phase detection support. There's an interview with some Panasonic reps from CP+ earlier this year where they claim that they have avoided phase detection so far because it can lead to artifacts in the image:
http://www.imaging-resource.com/new...2017-gh5-dev-story-on-chip-pdaf-affordable-4k

But Sony seems to have made it work, and if you are starting with a 20MP image and downscaling to 8MP (for 4K video) it seems like most of the video artifacts due to the phase detection pixels could probably be eliminated when downscaling. So I'm not sure I 100% buy this explanation. But then again, I am not a camera engineer.
 
Hi

ParagonFilmworks said:
While it appears improved the issue I have is with the AF is the "pulsing" effect and unfortunately it appears to be there still.
Click to expand...

It's how contrast auto detection works, you can't get rid of that pulsing effect, it's basically how the auto focus system samples the image to know where the focus point is. Phase detection works differently and can work out the distance of a subject. There are pros and cons to both systems.

https://www.creative-photographer.com/phase-detection-contrast-detection-autofocus/

Regards

Phil
 
Phil_D said:
It's how contrast auto detection works, you can't get rid of that pulsing effect...
Phil
Click to expand...

There was a video referencing the system and how Panasonic (a rep stated) that at the time their focus system was very good but other manufactures came out with DPAF etc. and they just aren't comparable. I certainly understand that statement and know such systems aren't comparable but I'm coming from C100's and I would just throw the Tokina on and turn on AF for gimbal work. Same thing I did with the GH5 (12-35 native). I've never had pulsing with the C100 granted they are totally different cameras but I expected the same results with a spot focus on the GH5.

I wish I could obtain the same results but it's back to MF on the gimbal and it's not the end of the world. It was nice to go from a close up to a wide with critical focus most of the way through the motion since the detail is much higher and tends to tell on you a bit more than a wide on the C100.

I hope it gets modified a bit more but if not I know the limitations and will work within them. It's also quite possible that it is an actual limitation with the system and can't be helped much more.
 
davedv said:
Since a smaller sensor (like the 1/3" sensor in the PX270) has a much greater depth of field, a lot more of the frame is likely to be in focus at any one time. An HD camera like the PX270 also has a lot less resolution (about 2 million pixels compared to 20 million for the GH5) which further reduces the demands on the autofocus system.

I believe most small sensor camcorders like the PX270 just use contrast detection autofocus, which is the same autofocus approach the GH5 uses. It's possible the GH5 autofocus system may actually be more advanced than the one in the PX270 since it is a few years newer. But even though contrast detection autofocus seemed to work ok for small sensor HD cameras, it just doesn't seem to hold up as well for larger sensor 4K cameras.

There are many large sensor 4K video cameras that rely exclusively on contrast detection autofocus, including cameras with 1-inch sensors like the Panasonic UX180, Sony PXW-X70, Sony PXW-Z150; 4/3-inch sensors like in the Panasonic DVX200 or GH5; Super 35 sensors like in the Sony FS5, FS7; full frame sensors like in the Sony A7S, and A7S II. And I'm not sure any of these cameras are seen to have excellent autofocus systems.

Most of the large sensor 4K cameras that have better video autofocus include some sort of phase detection autofocus system, like the Canon Dual Pixel autofocus (in the C100 mkII, C200, C300 mkII and various Canon DSLRs) or on-sensor phase detection with a lot of phase detection points, such as in the Sony a6300 and a6500. And perhaps it's not a surprise that at IBC, both Canon and Sony introduced new 1-inch sensor camcorders with their respective autofocus systems (the Canon XF400/XF405 and Sony PXW-Z90 and HXR-NX80).

Interestingly, the Olympus OM-D E-M1 Mark II (which has a very similar sensor to the GH5) has support for on-sensor phase detection, but it seems that the phase detection autofocus system is not used for video, where it reverts back to contrast detection. And so far Panasonic seems to have focused on improving their contrast detection system rather than adding phase detection support. There's an interview with some Panasonic reps from CP+ earlier this year where they claim that they have avoided phase detection so far because it can lead to artifacts in the image:
http://www.imaging-resource.com/new...2017-gh5-dev-story-on-chip-pdaf-affordable-4k

But Sony seems to have made it work, and if you are starting with a 20MP image and downscaling to 8MP (for 4K video) it seems like most of the video artifacts due to the phase detection pixels could probably be eliminated when downscaling. So I'm not sure I 100% buy this explanation. But then again, I am not a camera engineer.
Click to expand...

Thanks, nice post!
 
V2.0 is leagues better. Maybe the credit doesn't belong there fully because the same day Panasonic released new firmware for the 4/3 lenses too. It's a different camera.
 
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