Studio Comparison

By Sam Spencer and Rishi Sanyal

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 'Web', with the latter two offering 'normalized' comparisons to more fairly compare cameras of differing resolutions by ensuring equivalent viewing sizes.

With the a7 II, our main question was: has anything on the image quality (IQ) side changed over the first-generation a7? Taking a look around the scene at base ISO shows virtually identical images. Even a well-tuned eye cannot detect any difference in Raw IQ between the I and II versions of the a7 at base ISO. The JPEG engine also remains consistent between the two cameras. High frequency details exhibiting similar sharpness levels in Raw at ISO 100 look exactly the same between the two cameras when switched over to JPEG mode, and stay similar up to ISO 3200. The difference in JPEG noise reduction algorithms between the two cameras starts to show at ISO 6400, where you may notice a bit more grain in a7 II images. These differences become obvious at ISO 25,600, where low contrast detail is better preserved by the a7 II. The JPEG engine in the a7 II has a smarter noise reduction algorithm that tends to smear less details in exchange for leaving a bit more grain behind. That said, we'd still recommend you change the 'High ISO NR' setting from 'Normal' (default) to 'Low' in order to preserve more detail in low-light images.

High ISO Raw performance also remains unchanged, which isn't exactly a good thing. Using the same sensor as the a7 means somewhat dated low-light performance at high ISOs, which puts the a7 II at a disadvantage when compared to some of its peers. Although at base ISO the a7 II displays similar sharpness and resolving power as Nikon's D750, the D750 comfortably clocks in far better high ISO performance. The differences are quite visible, with the D750 pulling ahead by a full stop at ISO 6400, and perhaps even more than a stop at ISO 25,600, where the images from the D750 at ISO 51,200 look slightly less noisy than the a7 II's ISO 25,600 shot. It's not just the D750 that stays a stop ahead of the a7 II. The Canon 5D Mark III also shows similar results. When compared to its other a7 brethren, the a7s pulls ahead by nearly two stops as expected, and the higher resolution a7R shows better ISO performance compared to the a7 II, despite having 50% more pixels. In fact, in terms of ISO performance, the a7 II appears to fall near performance levels of the smaller, APS-C sensor in the Nikon D5300, showing similar noise in midtones. This somewhat nullifies the noise advantage one typically expects from larger sensor cameras, although, to be fair, it also speaks to performance increases in APS-C sensors.

The take-home here is that the a7 II shows a bit more refined JPEG processing at high ISOs, but otherwise shows identical performance to the a7 when it comes to image quality. And since the ISO performance of the a7 sensor is a bit dated, so is the a7 II's low-light performance when compared to the better full-frame cameras available today. That said, the a7 II's image stabilization might help get you back a couple stops of ISO performance by allowing you to use slower shutter speeds - as long as your subject isn't moving. But low-light performance isn't everything when it comes to a camera, and on the next two pages we examine Raw image quality in greater detail, especially as it pertains to dynamic range.