Sony Cyber-shot DSC-RX100 IV sensor review: Performance stacked in favor

70
DxOMark Sensor

Introduction

Specifications and Features

Sony’s RX100 series of premium-quality compacts for enthusiasts has proven hugely popular and garnered worldwide acclaim. The RX100 IV is the fourth iteration, and like the model it replaces, has a stabilized Zeiss Vario Sonnar T* 24-70mm (equivalent) f1.8-2.8 zoom and pop-up EVF, but in place of the 1.44m-dot res screen, it has a new 2.35m-dot OLED.

Although the pixel count remains unchanged and the image sensor utilizes the now commonplace back-side illumination, the RX100 IV uses what Sony is calling a “stacked CMOS” design. This new design incorporates recent advances in the supporting electronics with, for instance, on-chip DRAM and shorter-length circuitry, resulting in a physically closer buffer and allowing such features as high bit-rate (up to 100 Mbps), UHD video (albeit with five-minute max clips), and 960 fps slow-motion recording.

Like its predecessor, the RX100 IV has a 3.0-inch, 1.03m-dot multi-angle (tilting) LCD, and built-in Wi-Fi connectivity with NFC.

The Sony RX100 IV measures 4.0 x 2.4 x 1.6” / 10.2 x 6.1 x 4.1cm and weighs 10.51 oz / 298g, body only. It is available now at around $950 (USD).

Key Specifications

  • 20.1-Mpix Exmor RS BSI CMOS sensor
  • Zeiss Vario Sonnar T* 24-70mm (equivalent) f1.8-2.8 stabilized zoom
  • 2359k-dot OLED EVF
  • Bionz X image processor with ISO12800 max sensitivity
  • 3.0-inch 1.03m-dot multi-angle LCD
  • UHD (3840 pixel) video with S-Log2 Gamma
  • Slow-motion video option at 960 fps
  • 16 fps continuous still shooting
  • Built-in Wi-Fi connectivity with NFC

Excellent sensor scores for a one-inch type sensor

With an overall DxOMark sensor score of 70 points, the Sony RX100 IV sensor performs very well indeed and achieves a high mark for this size sensor. Color sensitivity is a high 22.9 bits, meaning it has relatively low chroma noise at low ISO, and dynamic range at base ISO is a wide 12.6 stops.

It’s not just a good result at base, however: DR is improved at every ISO setting. Even the low-light score of 562 ISO is an improvement of around 0.25 stop over similar pixel count one-inch type BSI sensors.

Sony_RX100_IV__Score__920

For a physically small sensor, the new 20-Mpix Exmor RS BSI CMOS chip ranks high, coming in at 116th in our database for sensors of all sizes. Performance ranks alongside recent Micro-Four-Thirds models and even APS-C-equipped DSLR models such as the Canon EOS 7D Mk II and EOS 760D.

Sony Cyber-shot DSC RX100 IV vs. Sony Cyber-shot DSC RX100 II vs. Sony Cyber-shot DSC RX100 III: Small but worthwhile improvement in sensor dynamics

With the new sensor architecture, the RX100 IV shows some very slight (and welcome) improvements in sensor performance over the conventional BSI sensor used in its predecessors, the RX100 II and III. The new sensor offers a slight improvement in dynamic range throughout the scope of ISO settings as well as a gain of around +0.25 stops in low-light performance.

Sony_RX100_IV__RX100_II__RX100_III__Dynamic_Range__920

A small improvement in DR can be observed not just at base ISO, but also throughout the ISO range

Sony Cyber-shot DSC RX100 IV vs. Canon Powershot G7X vs. Nikon 1 J5

The new sensor compares favorably with the class-leading performance of the 20-Mpix one-inch sensor in the Canon PowerShot G7X. With a DxOMark sensor score of 71 points for the Canon, the difference of one point is for the most part negligible, and the sensor performance of the PowerShot G7X is indistinguishable in real terms.

Still, it’s an excellent score, and although the relatively new Nikon 1 J5 isn’t that far behind, the new “stacked” sensor technology brings with it more that just a slight improvement in noise, dynamic range, and low-light performance — there’s the faster frame rates for video and stills. This includes the more useful 30/25/24 fps 4K (UHD) option, as opposed to the Nikon’s rather low 15 fps. Improvements in dynamics are similar between the Nikon and the Sony predecessor, indicating that they most likely share a related sensor.

Sony_RX100_IV__Canon_G7x__Nikon_1_J5__Colour_Sensitivity__920

Color sensitivity or chroma noise in the Sony practically matches the class-leading Canon

Sony_RX100_IV__Canon_G7x__Nikon_1_J5__Dynamic_Range__920

There’s no appreciable difference in DR between the Sony and the Canon, while the difference between them and the Nikon using the previous-generation BSI is clear in the graph

Conclusion

Although the increase in sensor performance is evolutionary rather than revolutionary, it’s still significant. The new stacked design (and accompanying processor) has allowed some remarkable increases in frame rates both with 4K capture and Full HD, notably the 30/35/24fps at 4K (UHD) and the slow-motion options up to 960fps. There’s also been an increase in still capture rates to 15 fps from 10 fps in the third-generation model. Advances like these are especially promising for future models with small sensors, but if it can be scaled to larger sensors, the potential benefits are equally intriguing.