After Sony has announced the new a7 III (Adorama/B&H/Amazon) full frame mirrorless camera, now next full frame mirrorless camera from Sony should be Sony a7S III, to replace current a7S II (a7S II was announced on September 11, 2015). According to Sony Rumors, Sony a7S III is rumored to be announced in the second half of 2018, around Photokina in September. Though NAB Show is in April, 2018, there is no rumors on a7S III to be announced in April.
Sony has officially announced the new a7 III full frame mirrorless camera today, you can check pre-order option at B&H Photo Video/Adorama/Amazon. a7III is a well-rounded camera suitable for both photo and video applications in a variety of working situations. Refined for improved speed and low-light performance, the full-frame 24.2MP Exmor R BSI CMOS sensor and BIONZ X image processor pair to realize an impressive 10 fps continuous shooting rate and improved autofocus performance for faster, more reliable subject tracking along with wide frame coverage. This updated Fast Hybrid AF System employs a combination of 693 phase-detection points and 425 contrast-detection areas for quicker acquirement of focus in a variety of lighting conditions, and also maintains focus on subjects more effectively. In addition to speed and AF, the processing improvements also help to realize greater image clarity and reduced noise throughout the sensitivity range from ISO 100-51200, which can further be expanded to ISO 50-204800. Video recording capabilities have also been extended for enhanced quality when recording UHD 4K video with the full width of the full-frame sensor to minimize moiré and aliasing. Additionally, benefitting both stills and video operation, the a7 III utilizes a 5-axis SteadyShot INSIDE sensor-shift image stabilization, which is now effective to minimize the appearance of camera shake by up to 5 stops.