The rumor is completely latest and published online that revealed Sony Alpha a7000 could use HDR feature sensor and will have dynamic range upto 15.5 stops. Still not cleared when to release but rumors say that it will be on late summer. However nothing more specs related news we got but it expected that the video may b 4K recording, weather sealed and fastest auto-focus speed.
Know how HDR video recording works:
To achieve true HDR video recording, the advanced Exmor RS camera sensor in Xperia Z changes the exposure every two lines of pixels. This creates a spatially varying exposure (SVE) array image, which is then used to make an image that is perfectly exposed in both dark and light areas.
To simplify the concept, for each frame the camera shoots one picture with two different exposure levels at the same time, one light and one dark. Then, an intelligent software algorithm is used to combine (synthesize) the two shots into one picture, pixel by pixel. This allows you to see the details of both the dark and the bright parts of the picture.
HDR for still images
With HDR for still images, the camera quickly captures the image twice with different exposure levels and stitches the two shots together to create one optimized photo. This way, HDR lets you capture clear photos even against strong backlight. HDR is automatically activated when Superior Auto detects scenes with strong backlight
source – sonyalpharumor.com