Monday, 14 November 2016

G85: Awesome video image stabilization in 4k

The recently announced Lumix G85 breaks new ground with the in-body image stabilization (IBIS) trickling down into more camera models. It also helps giving very good stabilization of video recordings. See a demonstration of how the sensor moves here.

To further illustrate the effectiveness of the image stabilization, I have compared it with the Lumix GH4. In the comparison, I used two pairs of lenses: The classic Lumix G 20mm f/1.7 pancake prime, and the Lumix G 14-42mm II basic kit zoom lens. I had both cameras mounted to a Desmond stereo bracket for the comparison:


Both cameras were recording 4k video at 30FPS, at maximum aperture. On the Lumix G85 I had the in-body image stabilization enabled, but not the additional E-stabilization. Both cameras were set to continuously autofocus during the video recording. Here are the results:






Image stabilization


What we see, is that the Lumix G85 is able to stabilize the video recording also with the Lumix G 20mm f/1.7, which doesn't have any optical image stabilization (OIS). And with the OIS enabled Lumix G 14-42mm II, the G85 does a better job than the GH4, as the G85 uses both the in-body image stabilization and the lens OIS at the same time.

This feature helps me a lot. When recording handheld footage in a dim light, I would previously use a non-stabilized prime lens, and had to apply software image stabilization in post processing, e.g., with Adobe Premiere Pro. That takes a lot of processing time, typically around 10 hours per minute of 4k footage in my experience. Now, I can use the Lumix G85 and avoid this extra processing for almost the same end result.

On the negative side, there is some noticeable hum from the sensor shake mechanism inside the Lumix G85. If you have very quiet ambient sounds, then you might get this hum picked up by the internal microphones.

There also appears to be somewhat less rolling shutter effects with the Lumix G85, but that could be a result of the improved image stabilization.

Autofocus


As for autofocus, it is disappointing to see that the Lumix G85 is way worse than the Lumix GH4, even if the GH4 isn't very good at 4k autofocus to begin with.

I would speculate that this comes down to processing power. Contrast Detection Autofocus (CDAF) and Depth From Defocus (DFD), the technologies used by Panasonic for focusing, require a lot of processing power. Supposedly, the Lumix GH4 has a quad core CPU image processor to be able to handle the video stream. Perhaps the G85 is not specified as with the same processing power, and cannot focus as fast.

With 1080p footage, though, I don't see much difference. The Lumix G85 focuses snappy enough during video recording when using Full HD 1080p resolution, in my experience.

Handling


Compared with the Lumix G7 predecessor, the Lumix G85 gets a slightly larger body, and a more pronounced grip. I think this is a good development, I think the camera body is still compact enough, and the extra size is important for ergonomics.

Compared with the Lumix GH4 (left below), it is slightly lower, and does not get the special ISO, WB and exposure compensation buttons behind the shutter:


Rather, these functions are accessible from the rear arrow buttons on the Lumix G85 (right below):


The Lumix G85 also loses the click ring around the arrow buttons, which you can see on the Lumix GH4, left above. However, I don't see that as a huge loss. Mostly, I only used the ring for switching pictures during playback while having a zoomed in view, a very useful feature. However, the G85 still allows the same by using the front click ring for switching images, so I am happy.

Both cameras have the focus selectors at the same place. The Lumix G85 improves upon the GH4, in the sense that this selector is not as stiff to operate. I like the newer one better.

Also, the G85 moves the playback button to the right side, very good for one handed operation.

As the G85 is lower, there is less space for sockets. The microphone socket is in front of the LCD hinge, meaning that you cannot flip the LCD all the way out, and at the same time lay it flat (GH4 to the left, G85 to the right):


If you are like me, and like to hold the camera at waist height and look down into the LCD panel, this is a small inconvenience, but not a problem. The camera still works well for me.

Conclusion


So far, I think the Lumix G85 is a great camera, the best from Panasonic so far. Compared with the Lumix GH4, you lose the V-Log profile capability, which could be a deal breaker for some professional use.

However, the Lumix G85 still retains the Cinelike D and Cinelike V profiles, which give some extra headroom for color grading.

The Lumix G85 also tops out at only 28MBPS resolution for 1080p footage, while the Lumix GH4 could record at 100MBPS, and even 200MBPS with All-I-frames mode, which is hardly needed for anyone. I don't think this will be a problem for most use, though.

Also, as you see here, the autofocus performance during 4k video recording is not very impressive with the Lumix G85, but future firmware upgrades could improve this slightly. This doesn't bother me too much. Usually, I prefocus by half-pressing the shutter release button, and then I switch to Manual Focus (MF) before starting the video recording. This is why I also like the better AF mode selector on the Lumix G85.

The battery life appears to be worse on the G85, compared with the GH4. It is probably a good idea to pick up a spare battery for the Lumix G85.

From my point of view, the Lumix G85 will replace the Lumix GH4 as my daily use camera. The Lumix GH5 will be released some time early 2017, but it will probably not get IBIS. Having used the G85 with IBIS, I am not sure I would like to go back to a camera without this feature.

8 comments:

  1. It would be interesting to see an IBIS comparison with one of the Olympus stabilised bodies.

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    1. I will make this kind of comparison soon, when the new Lumix G85 firmware comes in around one week. This could change the nature of the G85 stabilization, so it is best to wait.

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  2. Have you tried increasing CAF sensitivity (new feature in G85)?

    There are videos showing that his greatly improves CAF speed in video as well.

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    1. Yes this is what I was curious about. It seems the default setting is for exceedingly slow AF transitions, presumably to optimise smoothness. However I've seen some vids demonstrating that by altering the new AF-C speed option one can improve AF acquisition performance markedly for video.

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    2. Yes, I have tried to set the camera autofocus sensitivity to +2. It is still way slower to focus in 4k video recording than the GH4.

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  3. How would you rate the G85 for stills vs the E-M5ii?

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    Replies
    1. I haven't looked very thoroughly into this, but so far I'd say they are at the same level when it comes to stills image quality. Neither camera is significantly better.

      When it comes to ergonomics, though, I think the Lumix G85 is head and shoulders ahead of the Olympus OM-D E-M5 II. But then again, I do like the Panasonic SLR layout cameras. For example, I often operate the drive mode, and it is very easy to use the switch on the left shoulder.

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