Panasonic GH5 review: The ultimate hybrid video and stills camera

Panasonic GH5 review: Video capture

The Panasonic GH5’s video mode is the star of the show and its 60fps 4K capture and 10-bit encoding set it apart from anything else at this price. Encoding at these settings is at 150Mbits/sec, which strikes a sensible balance of image information against file size. The 10-bit mode also uses 4:2:2 chroma subsampling, which means higher-resolution colour information compared to the usual 4:2:0. 10-bit and 4:2:2 are only available at 4K at 24/25/30fps and Cinema 4K at 24fps but that covers most people’s needs.

Panasonic also offers a colour profile called V-Log L, which records flat colours akin to shooting RAW photos. According to Panasonic it increases the dynamic range of footage from 10 to 12 stops. V-Log L is a $100 USD upgrade and I’d imagine that anyone who’s interested in 10-bit recording will consider it an essential purchase.

Software compatibility for 10-bit files is currently limited but I was able to work with them in Adobe Premiere Pro CC 2017. Direct comparisons with 8-bit footage showed a subtle improvement after applying heavy colour correction to footage. Popular distribution platforms such as Blu-ray and YouTube all use 8-bit, 4:2:0 colour so the benefit will only be felt during the editing process, particularly for aggressive colour correction and green-screen masking. Owners will need to decide whether these benefits are worth the drawbacks in terms of software compatibility and processing overhead, but it’s great to have the option.

The V-Log L colour profile provided more obvious benefits, revealing extra details in highlights and shadows and reducing posterisation artefacts after colour correction. Significantly, it was much more effective than the Cinelike D profile that’s included as standard for the same purpose. The ability to use Look-up tables (LUTs) to apply colour profile presets gave an editing experience that was closer to working with RAW files than JPEGs. Premiere Pro CC slowed significantly when working with LUTs and 10-bit footage, though. Selecting V-LogL on the camera pushes the base ISO speed up from 200 to 400, and there’s a bit of noise visible in darker parts of the frame but it’s not too hard to hide this in the shadows with careful colour correction.

^ Comparing details of frames of an overexposed sky shot using Cinelike D and V-Log L colour profiles in both 8-bit and 10-bit. I’ve been able to recover the blue sky using Premiere Pro CC’s colour grading tools, but there’s blocky posterisation of colour in the Cinelike D footage at both 8- and 10-bit. Graded V-Log L footage gives significantly better results, although there’s still some posterisation in the 8-bit V-Log L footage. 10-bit V-Log L comes out on top. [click image to enlarge]

^ A shadier corner of the same scene, shot with darker exposure settings. The shadows are almost black in the Cinelike D footage. I’ve been able to recover some shadow detail using colour grading but there’s quite a bit of noise as a result. V-Log L makes it easier to recover shadow detail without excessive noise, and there’s slightly more detail in the grass at the bottom-left of the crop in the 10-bit version. [click image to enlarge]

^ Comparing 8-bit 4:2:0 and 10-bit 4:2:2 for chroma keying (using Premiere Pro CC’s Ultra Key effect). The higher-resolution colour information in 4:2:2 footage means the mask is sharper but the difference is pretty subtle

^ This animated GIF directly compares the 8-bit 4:2:0 and the 10-bit 4:2:2 results on a static subject. This is a 1:1-pixel crop of 4K output. Note that the GIF format limits this image to 256 colours. [click image to enlarge]

^ The same comparison, but this time with graded V-Log L footage: the difference is more pronounced. [click image to enlarge]

The GH4 used a 1:1 pixel crop for its 4K capture, which meant it just used an 8-megapixel area of its 16-megapixel sensor. The GH5 always uses the full width of its 20-megapixel sensor, so its 5,184 x 2,916 frames are resized to 3,840 x 2,160 for 4K output. That means a lot more work for the camera’s processor but details should be a little sharper as a result. It also means lenses have the same equivalent focal length regardless of which recording mode you’re in.

In practice, the boost to image quality is subtle, but direct comparisons with our studio scene taken with the GH4 revealed smoother fine details such as strands of hair. I also noticed that the subtle grain of noise in the GH4’s 4K output at ISO 200 had disappeared in the GH5.

^ Comparing our studio scene with footage from the Panasonic GH4 and GH5 (both captured at 1/50sec, f/5.6, ISO 200, Standard colour profile). There’s less noise in the GH5’s output and fine details are a tad smoother

The faster processor allows 1080p capture at frame rates up to 180fps, delivering 7.5x slow motion at 24fps playback. Disappointingly, the anti-aliasing algorithm is lower quality for slow-motion 1080p capture compared with normal-speed capture, leading to slightly blocky details. It’s an issue that’s shared with the GH4 but I’d hoped the GH5’s faster processor would have resolved it. After all, it’s applying higher quality anti-aliasing for 4K at 60fps, which has an even higher pixel throughput. Still, this probably won’t upset many people.

^ Details from 1080p footage captured at 25fps and 180fps (the latter for slow-motion playback). The 25fps image is slightly sharper, most notably on the dial on the robot

^ It’s not particularly noticeable in real-world footage, though

^ 4K 50p footage from the GH5: what’s not to like?

Other video-related niceties include the introduction of in-camera wave and vector scopes. It’s now possible to set the shutter speed and aperture manually (to control motion blur and depth of field respectively) but leave the ISO speed on Auto for automatic exposure control. There’s also the promise of All-Intra recording at 400Mbit/sec via a firmware update this summer. All-Intra encoding describes each frame from scratch rather than as an update to the previous frame, which produces enormous files but virtually eliminates compression artefacts, even in busy, fast-moving scenes.