Following NIKON & then CANON, last year, PANASONIC have released their own 2 new models, Lumix S1 (24.2MP sensor) & a pro-oriented Lumix S1R (47.3-megapixel) Full-frame Mirrorless cameras on 1 Feb.

The S1 & S1R will be available in early April.

Panasonic Lumix DC-S1 - $2499 body-only or $3399 with 24-105mm F4 lens.
Panasonic Lumix DC-S1R - $3699 body-only or $4599 with 24-105mm F4 lens.

See DPReview 1 Feb - Panasonic S1 will cost $2499 body-only and feature oversampled 4K/30p
See DP Review 3 Feb - Panasonic's new Lumix DC-S1 and S1R: What you need to know

See Also....

DarkLantern blog - darklanternforowen.wordpress.com

Panasonic Lumix S1 Key Specifications:

- 24MP full-frame CMOS sensor
- Depth from Defocus contrast-detect AF system
- 5-axis in-body 'Dual IS' system
- Fully weather-sealed
- 96MP 'High Res' mode
- 6 fps bursts with continuous AF
- 5.76M-dot EVF
- Dual-hinged 2.1M-dot touchscreen LCD
- UHD 4K/60p video capture (1.5x crop); Oversampled 4K/30p with no crop
- 10-bit HLG built-in, optional 4:2:2 V-Log
- One XQD and one SD card slot
- 380 shots/charge using LCD
- USB charging, including from laptop/tablet chargers and portable power banks

Panasonic Lumix S1R Key Specifications:

- 47MP full-frame CMOS sensor
- Depth from Defocus contrast-detect AF system
- 5-axis in-body 'Dual IS' system
- Fully weather-sealed
- 187MP 'High Res' mode
- 6 fps bursts with continuous AF
- 5.76M-dot EVF
- Dual-hinged 2.1M-dot touchscreen LCD
- UHD 4K/60p video capture with 1.09x crop and pixel binning
- One XQD and one SD card slot
- 360 shots/charge using LCD
- USB charging, including from laptop/tablet chargers and portable power banks

DarkLantern blog - darklanternforowen.wordpress.com

One thing that jumps out to me, is that Panasonic are using 'contrast-detect' autofocus - I'm pretty sure Nikon & Canon would be using phase-detect AF (a stand-out feature of their DSLRs).

I know from my own modest experience with my Olympus EM-10 that Contrast-detect is inherently compromised in low light (low contrast) conditions for starters.

DarkLantern blog - darklanternforowen.wordpress.com