Studio test scene

Our latest test scene is designed to simulate both daylight and low-light shooting. Pressing the 'lighting' buttons at the top of the widget allows you to switch between the two. The daylight scene is shot with manually set white balance aimed at achieving neutral grays, but the camera is left in its Auto setting for the low-light tests (except Raw, which is manually corrected during conversion). We also offer three different viewing sizes: 'Full', 'Print', and 'Comp', with the latter two offering 'normalized' comparisons to more fairly compare cameras of differing resolutions by using matched viewing sizes. The 'Comp' option chooses the largest-available resolution common to the cameras being compared.

Raw Performance

Sony made no claims of improved image quality from the new 'stacked' BSI-CMOS sensor at its announcement, but frankly we were hoping that the stacked sensor might have allowed for some of the electronics to be further pushed off the imaging sensor to allow for a larger active pixel area. Unfortunately, comparing Raw low light, high ISO noise performance between the Mark III and IV versions essentially shows no advantage to the new sensor design this time around.

A worthy competitor to the RX100 IV is one of our favorite compacts, the Panasonic LX100, so it's worth noting that the LX100 has an edge in sharpness, as its larger sensor puts less stringent demands on the resolving power of its lens. Low light performance slightly favors the LX100's larger sensor, but only by a modest half stop or so, far less than the 1 EV theoretical advantage the 2x larger sensor of the LX100 should enjoy, all else equal. This speaks to the high efficiency of the RX100 IV sensor, which allows it to punch above its weight. At 20.2MP, the RX100 IV bests the LX100 in resolution, not to mention in overall size.

JPEG Performance

The JPEG engine has been substantially improved in the RX100 IV over the Mark III. In fact, it's safe to say the RX100 IV JPEG engine is one of the better ones around in certain respects. Context-sensitive noise reduction has been substantially reduced, meaning fewer artifacts caused by transitions between regions where noise reduction has and hasn't been applied. The borders of the color patches look far more natural because of this, and the decreased noise reduction means that low contrast detail is retained even at high ISOs. Far more detail is preserved than Canon's G7 X, which obliterates low contrast detail readily despite fairly conservative overall noise reduction.

Sharpening has also been tamed: the large radius, somewhat over-aggressive sharpening we saw with the RX100 III has been dialed back, resulting in less pronounced sharpening halos around edges, which were particularly evident in the borders around color patches in our Gretagmacbeth chart. This is a welcome tweak: we often found out-of-camera JPEGs from the RX100 III to be irreversibly over-sharpened.

Electronic Shutter

New to the RX100 IV is a fully electronic shutter option. This allows for fully silent operation (though the leaf shutter was already very quiet) and, more importantly, shorter blackouts during continuous shooting due to the lack of mechanical shutter actuation. The fully electronic shutter helps the camera attain a higher frame rate, as well as maintain formidable autofocus during continuous shooting. Importantly, the electronic shutter appears to have no noise cost associated with it, which means you can use it - and the camera will automatically do so in bursts - without worry of any impact on image quality, save for a slight increase in the potential for rolling shutter with fast moving subjects. We'll dive into the potential impacts of the electronic shutter on dynamic range on the next page.