When comparing Sony a7R II vs Panasonic Lumix S5 IIX, the Slant community recommends Panasonic Lumix S5 IIX for most people. In the question“What are the best mirrorless cameras?” Panasonic Lumix S5 IIX is ranked 2nd while Sony a7R II is ranked 6th. The most important reason people chose Panasonic Lumix S5 IIX is:
Good video quality, features and performance.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Excellent image quality
The camera has a 42MP BSI-CMOS sensor. Both in good light and low light, whether you're shooting in RAW or JPEG, the images have excellent detail. You can check out detailed studio tests over at DPReview.
Pro Great Auto ISO implementation
Pro In-body image stabilization
Pro Good 4K video
The camera can capture 4K30 (at up to 100Mbps), 1080p60 and 720p120 video internally and save to XAVC S with S-Log2 color profile. The video is detailed with little noise both in good light and in low light.
It's worth noting that 4K video is slightly better when shooting using the Super 35 region of the sensor instead of the full sensor region while 1080p performs better when shot at full width of the sensor and downsampled.
Pro The camera can be used while it's charging over USB
Pro Good AF for video
Camera's autofocus is fast and decisive. And it allows a good degree of control over how it behaves. You can adjust the focusing speed as well as sensitivity.
Pro Face detection AF for video
Pro Good video shooting tools
The camera has a zebra and focus peaking tools allowing you to monitor focus and exposure while shooting.
Pro Flat color profile for video
Pro Has a completely silent mode
If set up to use electronic shutter, the camera makes zero noise.
Pro Excellent AF point coverage
399 phase-detect AF points and additional 25 contrast-detect AF points.
Pro Excellent continuous AF
Both in good light and in low light.
Pro Good noise reduction control
Pro Flat color profile available for increased dynamic range
A flat color profile captures footage in low contrast and higher dynamic range allowing for easier color grading in post-production.
Pro Great dynamic range
Pro Excellent low-light capabilities
The camera has class-leading high ISO capabilities. A look at real-world high ISO shots can be found here.
Pro Video quality
Good video quality, features and performance.
Pro SSD recording
Can write directly to external SSD devices (up to 2TB) over its USB-C socket.
Pro Good stablization
Cons
Con Cumbersome menu system
The camera has a plethora of poorly organized menu items.
Con Continuous shooting is limited to 5fps
With 5 frames per second the camera lags behind other cameras. If you're looking to shoot sports, this camera might not be the best choice.
Con Limited selection of native lenses
Sony has a comparatively little selection of lenses and while you can add an adapter to use lenses from other manufacturers, that choice comes at the expense of some functionality.
Con Screen is not touch sensitive
Switching AF points could be simplified by having a touchscreen.
Con Poor battery life
Con Lacks in-camera RAW conversion
Con Continuous shooting is at a reduced dynamic range
Con Eye-AF and Lock-on AF is not available for 3rd party lenses
Con Eye-AF and Lock-on AF is not available in video
Con Lacks direct control over autofocus points
Con Sinister black look
A question of taste of course, it seems to be an "award-winning design".