First, let’s clarify the concept of dynamic‑range value. For example, a dynamic range of 120 dB means the illuminance ratio between the brightest and dimmest areas distinguishable by the camera is 1,000,000:1, namely 10⁶:1.

10⁶:1 corresponds to 120 dB. The industry‑standard formula for wide‑dynamic‑range ratio is:

dB = 20 log (Illuminance of brightest area [lx] / Illuminance of dimmest area [lx])

Calculation example: 20 log(1 000 000/1) = 20 × 6 = 120 dB

While comparing the differences between IMX334 and IMX678, we notice that IMX678 adopts a distinctive HDR technology known as Clear HDR.

DOL HDR (Digital‑Overlap High Dynamic Range) is a widely‑known HDR solution. Taking advantage of the rolling electronic shutter, it interlaces exposure and readout to achieve “quasi‑simultaneous” exposure.

The image sensor first captures a short‑exposure frame optimized for bright areas, then a long‑exposure frame optimized for dark areas. The two frames are overlapped and fused to generate the HDR output.

Nevertheless, a slight time offset exists between the two frames. When shooting fast‑moving subjects, artifacts such as blurred contours or color shifts may appear on moving parts. Besides, DOL‑mode HDR fusion is generally processed on the ISP, which consumes main‑chip computing resources.

By contrast, Clear HDR works as follows: the image sensor simultaneously captures a low‑gain frame for bright scenes and a high‑gain frame for dark scenes, and then performs frame overlay and fusion.

Since both images are acquired at the same instant, artifacts like color distortion are avoided even for high‑speed moving subjects. This makes Clear HDR ideal for applications capturing fast‑moving objects, such as traffic surveillance and dashcams, especially for tunnel‑transit scenarios.

Differences between DOL HDR and Clear HDR

1. In DOL mode: the sensor captures two frames sequentially — one long‑exposure frame and one short‑exposure frame.
2. In Clear HDR mode: the sensor captures two frames concurrently — one low‑gain frame for bright regions and one high‑gain frame for dark regions.

Per Sony’s official statement: “To generate the final image, the camera needs to fuse these output frames. IMX585 can perform on‑sensor fusion when Clear HDR is enabled.”

Excerpt from IMX678 datasheet regarding STARVIS 2:

STARVIS 2 is a registered trademark or trademark of Sony Group Corporation or its affiliates. STARVIS 2 is a back‑illuminated pixel technology for CMOS image sensors targeting security cameras. It delivers sensitivity of 2000 mV or higher per 1 µm² (color sensor, measured under 706 cd/m² light source, F5.6, equivalent to 1 s integration time). With identical pixel size and single‑exposure mode, its wide dynamic range (12‑bit AD) is 8 dB higher than STARVIS. It achieves superior image quality in both visible and near‑infrared spectrums.

In short, IMX678 offers 8 dB higher dynamic range than IMX334.

IMX334 is gradually phasing out of the market. The IMX678, a STARVIS 2‑grade image sensor with Clear HDR, can deliver full performance when paired with a suitable ISP.