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Asmundma

GH5 focus excellence

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So I originally wasn't going to post this video because I know there are few fans of 4K60p. That's OK, I love it. But since this is a thread on 'focusing excellence', it's entirely appropriate for me to post this. The video was shot yesterday at the Queens Zoo in N.Y. I used a variety of AF approaches (no MF at all), including 1-Area, Tracking AF, CAF and focus lock. The subject and its movement dictated which technique I chose.

Interestingly, the shot of the bear toward the end, is something that's eluded me with both the A6300 & A7Rii. It's so difficult that my wife said, "What's the point, it won't come out". I've taken the same shots of that same bear, and for whatever reason (the dark fur coupled with the bear's movement?), both Sony's would only hold focus for two or three seconds before losing it. In the interest of full disclosure, I did have one GH5 shot of this bear that wound up on the cutting room floor due to a misfocus, but that's still a 50% hit rate for a difficult subject even for PDAF. Everything else I shot was absolutely fine.

 

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Ken, I am seeing micro vibration in your video shooted with 14-140mm lens. Is the GH5 IBIS working properly? The 14-140mm OIS makes strong vibration but DUAL IS should fix it. This video needs post stabilization. AF works quite well. I dont see hunting. There is still not very difficult movement, just slow walking at constant speed.

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Well I can tell you that shot of the bear toward the end is precisely the same shot I've tried with both the A7Rii and A6300 (same exhibit, same bear). Both held focus for about 2-3 seconds, despite their PDAF. I'm not sure if the bear's dark fur presents a difficult task, but I was able to hold focus longer with the GH5 than the PDAF of the Sonys. Go figure. 

As for the micro vibration, I was shooting at close to a 400mm FL (FF equivalent) for many of these shots. I was at the max of the lens plus I used the lossless 1.4 ETC of the camera. The birds were relatively far away. So yeah, without being locked down, I can see a bit of micro vibration in some of these long shots. If you think that's bad, you should see similar shots with Sony's IBIS. This is far far better. I'm actually quite happy being able to hand hold at these focal lengths with just that amount of movement. Coming from Sony's IBIS, this is a delight. :) Just remember that no IBIS will create a locked down look at focal lengths like these.

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6 minutes ago, Ken Ross said:

As for the micro vibration, I was shooting at close to a 400mm FL (FF equivalent) for many of these shots. I was at the max of the lens plus I used the lossless 1.4 ETC of the camera. The birds were relatively far away. So yeah, without being locked down, I can see a bit of micro vibration in some of these long shots. If you think that's bad, you should see similar shots with Sony's IBIS. This is far far better. I'm actually quite happy being able to hand hold at these focal lengths with just that amount of movement. Coming from Sony's IBIS, this is a delight. :) Just remember that no IBIS will create a locked down look at focal lengths like these.

Your clips at max tele are better than mine with GH4 + 14-140mm OIS only. Still my clips with 100-300mm MEGA OIS at 140mm are little more stable without IBIS (GH4). Olympus IBIS makes micro vibration too with a tele lens. I wonder how good is the new 100-300mm II POWER OIS with non IBIS body.

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22 hours ago, Ken Ross said:

Well I can tell you that shot of the bear toward the end is precisely the same shot I've tried with both the A7Rii and A6300 (same exhibit, same bear). Both held focus for about 2-3 seconds, despite their PDAF. I'm not sure if the bear's dark fur presents a difficult task, but I was able to hold focus longer with the GH5 than the PDAF of the Sonys. Go figure. 

As for the micro vibration, I was shooting at close to a 400mm FL (FF equivalent) for many of these shots. I was at the max of the lens plus I used the lossless 1.4 ETC of the camera. The birds were relatively far away. So yeah, without being locked down, I can see a bit of micro vibration in some of these long shots. If you think that's bad, you should see similar shots with Sony's IBIS. This is far far better. I'm actually quite happy being able to hand hold at these focal lengths with just that amount of movement. Coming from Sony's IBIS, this is a delight. :) Just remember that no IBIS will create a locked down look at focal lengths like these.

140mm (280eq) on my GX80 is miles ahead stability wise than the 200mm f4 on my A7sii - different planet altogether. 

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In an interview with Panasonic's Dir. of Imaging business, Yosuke Yamane tells DPReview

‘On-sensor phase detection doesn’t work any darker than F8, [which can be a problem in video]. It’s not necessarily true that phase detection is better than DFD plus contrast detection.’

I think they also used to claim that OIS was superior to IBIS for video. He also adds that the development cost of phase detect and putting it in all their sensors would be tremendous. I don't see why anyone would normally be shooting at f/11 or f/16 on a m43 sensor anyhow, so that's pretty lame if you ask me. So it all comes down to expenditure.

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^

And here's the review by One Orbit Studios:

 

"The GH5 uses a contrast detection system, which utilizes 225 Auto Focus points and a 480 fps drive speed. In this video I go over two Auto Focus options - Autofocus Flexible (AFF) and Autofocus Single (AFS). I do not cover Autofocus Continuous (AFC) in this video. I found AFF to perform just as well if not better than AFC when tracking moving subjects.


All focus tests performed with the version one of the Panasonic Lumix 12-35mm f2.8. To maintain consistency between all the tests, the speed and reliability of the autofocus system system was tested in the same lighting conditions. Below is a description of the 6 Auto Focus Modes covered in this video:

*Autofocus Flexible or AFF. This option is good for filming in situations were the subject moves unpredictably. Like AFC, this mode will attempt to anticipate the movement of the subject.


1. The first test was performed with the Face/Eye Detection mode. This mode recognizes a subjects face by displaying a square outline. The subjects eyes are tracked with two intersecting lines.

Notes:

- Focus adjusts well when subjects moves towards and away from the camera.

- Rapid movement out of the frame and the GH5 handles focusing well.

- Does adapt well to obstructing the view of the subject.

- Of all the Auto Focus modes, Face/Eye Detection performed the best in low light.


2. The second test was performed with the Tracking mode. To set a Tracking point on your subject simply touch the screen.

Notes:

- Tracking point expands and contracts with subject distance.

- Focus Speed is slow to adjust when moving towards and away from the camera.

- Rapid movement out of the frame and the GH5 struggles to Track the subject and maintain focus.

- Tracking mode does not adapt well when obstructing the view of the subject.

- Very easy to through the Tracking point off.

- Tracking mode performs worse in low light.


*Autofocus Single or AFS. This option is good for filming in situations were the subject is stationary. The remaining tests were performed with a Nikon DSLR in the foreground and a group of Lenses set up in the background.

3. The third test was performed with the 225-Area mode. This mode utilizes up to 225 Autofocus points. This mode is effective when your subjects are not in the center of the frame.




Notes:

- Focus speed was slow to pull subjects close to the camera in focus.

- There was some focus hunting when pulling subjects further from the camera in focus.

- Focus hunting becomes worse in low light.




4. The fourth test was performed with the Custom Multi mode. Among the 225 Autofocus points, this mode enables you to set a custom shape around the subject.


Notes:

- Was able to pull subjects close to the camera in focus.

- This mode Failed to focus on subjects further from the camera.

- Not reliable.


5. The fifth test was performed with the 1-Area mode. This mode sets one area of focus on the subject.


Notes:


- Focus speed was slow to pull subjects close to the camera in focus.

- There was some focus hunting when pulling subjects further from the camera in focus.

- Focus hunting becomes worse in low light but slightly better than 225-Area mode.


6. The sixth test was performed with the PinPoint mode. This mode helps you achieve a more precise focus point on your subject. Tapping on the subject will activate a zoomed in preview of the focus area. You can also slide the cursor on the screen to specify the focus point. You do lose the zoom preview once you press record.


Notes:

- Focus speed was slow to pull subjects close to the camera in focus.

- There was some focus hunting when pulling subjects further from the camera in focus.

- Focus hunting becomes worse in low light.

- Overall this performed just as well as the 1-Area mode.


In summary, the GH5 autofocus system is not good for tracking fast moving subjects. I would recommend using the Face/Eye Detection mode in well lit scenes with high contrast. I would avoid the Tracking and Custom Multi mode, which as you saw were very unreliable. Focus speed was not great but was consistent in the 1-Area and PinPoint modes. In general, the GH5 produced a lot of focus hunting through out our low light tests.

List of Auto Focus modes best to worst:

1. Face/Eye Detection -AFF
2. Pin Point -AFS
3. 1-Area -AFS
4. 225-Area -AFS
5. Tracking -AFF
6. Custom Multi -AFS
"

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