While the Panasonic GH5S looks nearly identical to the standard GH5 on the outside, the redesigned sensor makes due with roughly half the megapixels. However, fewer megapixels on the same size sensor means the individual pixels can be much larger, increasing their light sensitivity and reducing noise.
The GH5S is the first Lumix camera to reach ISO 51,200 without using the extended ISO option, while still providing enough megapixels for 4K video. Thanks to the multi-aspect ratio design, videographers will be able to take advantage of the maximum sensor area possible in both Ultra HD (3,840 x 2,160) and cinema 4K (4,096 x 2,160) resolutions.
While the move to reduce megapixels in a new generation of camera isn’t unheard of — the Nikon D7500 has fewer megapixels than the D7200, for example — the GH5S is an alternative to the GH5, not a replacement. Sony does something similar with its full-frame mirrorless cameras, with the low-light and video-focused A7S series complementing the high-resolution, photography-focused A7R series. That means creatives can choose whether the higher still megapixel count or enhanced low light performance works best for their workflow.
That doesn’t mean the GH5S doesn’t offer something for still photographers, though. It can shoot 14-bit RAW files at up to 10 frames per second (7 FPS with continuous autofocus). Still shooters can also take advantage of the multi-aspect ratio sensor to maximize resolution and field of view, meaning users are no longer stuck with the 4:3 ratio if they want to access the full sensor. On the standard GH5, any other ratio is simply a crop from the 4:3 area, but now users can select the photographic standard 3:2 ratio without losing field of view.
Panasonic also enhanced the 225-point autofocus system to perform better in low light. It still uses the quick Depth from Defocus technology, but is now sensitive down to a very impressive -5EV.
Creatives working in the dark can also enhance the sensitivity of just the electronic viewfinder only using a new feature called Live Boost. The setting brightens the electronic viewfinder without affecting the actual image. Combined with options for a 20x magnification using manual focus, the viewfinder choices are designed for extreme low light conditions such as long-exposure astrophotography.
While the GH5 was the first mirrorless camera to shoot Ultra HD 4K video at 60 frames per second, the GH5S extends that capability to the cinema 4K resolution — another world first. Additional video perks include 4:2:2 10-bit internal recording (up to 4K/30), Hybrid Log Gamma (HLG) support, and timecode in and out for synchronization with multiple cameras.
The GH5S can also shoot time-lapses and 2.5x slow motion in 4K or up 10x slow motion in Full HD. 4K Photo mode returns, although the sensor lacks the resolution for the 6K Photo mode found on the GH5.
The Panasonic Lumix GH5S is slated to arrive on February 2 with a list price of $2,499 (body only), putting it $500 above the GH5. A new battery grip and microphone adapter will also be released.