The heart of the difference between the GH5 and the GH5s is the sensor. Panasonic reverted to the old days of the GH1 and GH2 by using a multi-aspect sensor with an optical low-pass filter (OLPF). It has a true 10.2-megapixel resolution, the perfect size to capture DCI Cinema 4K (4,096 × 2,160) without pixel binning or line skipping. While that ensures crisp, sharp video, it means that it actually has a lower resolution than an iPhone for photos.

The GH5s is also missing the GH5's in-body stabilization (IBS), a big negative for photographers. That might be because many video shooters don't rely on that for handheld shots. It simply doesn't smooth things out enough and can cause unwanted lag and glitches in pans, dollies and other camera moves. It can do that even if you turn it off, because in cameras with built-in IBS, the sensor is never rigidly fixed.

Reducing resolution and eliminating stabilization has further benefits. With larger pixels, the sensor can gather more light, making the GH5s a better night shooter than the GH5. That's further aided by the "dual native ISO" design, which allows for less noisy video at higher ISO settings.

And with no bulky stabilization electronics around the sensor, it has a slightly wider field of view than its photo-centric sibling, with a 1.8x crop factor instead of 2.0x for DCI 4K. That's a huge plus, considering that Micro Four-Thirds is the bottom rung in sensor sizes, as compared with full-frame and APS-C -- the more you can get out of it, the better. Also, with a multi-aspect sensor, the field of view is the same regardless of which aspect ratio you choose, including for 17:9 Cinema 4K (DCI).

For video, the GH5s can't be touched. You can shoot 4,096 x 2,160 at up to 60 fps, with 10-bit (a billion) colors and professional 4:2:2 color subsampling. Choose between long-GOP, MPEG-type codecs at up to 150 Mbps or, for easier editing, ALL-I, frame-by-frame video at a stellar 400 Mbps.

All of that jargon means that you can grab very high-quality, HDR video and change it substantially afterwards. Aiding that further is the "VLog-L" color profile, which will give editors the maximum dynamic range to tweak colors. (That was available on the GH5 too but cost around $100 extra.) If slo-mo is more your thing, the GH5s can capture DCI 4K at reduced 8-bit, 4:2:0 quality levels at up to 60fps, or 1080p at a time-stopping 240 fps.

No other mirrorless or DSLR cameras, including models like Sony's A7R III and the Nikon D850, offer 4K with 10-bit internal recording. That's a shame, because Sony's large-sensor cameras offer a much different look for video than the GH5s, but the lower recording quality limits their usefulness for video. If you want to relate it to stills, it's like offering only JPEGs instead of RAW.

There are a few other changes from the GH5. The GH5s supports 14-bit RAW photos, better than the 12-bit GH5, so there is that nod to photographers. The GH5s retains the GH5's 3.5mm microphone input, but it supports phantom power and line levels so that you can use professional microphones. The EVF runs at a faster 120fps, and picky cinema folks can even output images with look-up table (LUT) presets. Oh, and there's that "REC" button, colored bright red so you don't mix it up with the shutter release, and to differentiate it visually from the GH5.