Image quality

Key takeaways:

• JPEGs retain very high levels of detail at both low and high ISOs
• Noise reduction strikes a slightly different balance compared to the a7R IV, opting to reduce more luminance noise at the slight cost of fine detail as light levels drop
• Colors are improved: richer yellows, less magenta-tainted blues, warmer greens
• Class-leading Raw dynamic range compared to professional action / sports cameras
• Almost class-leading dynamic range compared to high-resolution full-frame peers
• ISO invariant over two ranges: 100-400, 500-102,400

Studio test scene

Our test scene is designed to simulate a variety of textures, colors and detail types you’ll encounter in the real world. It also has two illumination modes to see the effect of different lighting conditions.

Raw

In terms of Raw detail capture, the Sony a1 turns in a really impressive performance, easily on par with similar-resolution competitors across the scene. In fact, you have to look pretty closely to spot any extra detail extracted by the Sony a7R IV’s higher-resolution sensor. The Sony a1 can be prone to false-color artifacts though, just like the other options here, which will require a bit of work in post to remove.

Despite being built to have absolutely insane readout speed, which often comes at a noise cost, the Sony a1 performs similarly well to the Canon EOS R5 at higher ISO values, and comes in a bit behind the Nikon Z7 II and a little ahead of Panasonic’s Lumix DC-S1R. Compared to its pro-oriented peers, the a1 remains competitive, falling perhaps a tad bit behind the Canon EOS-1D X III and the Nikon D5, likely due to its increased pixel count.

JPEG

Moving on to JPEGs, we can see that the Sony a1 has fairly aggressive default sharpening, and looks like it’s been ‘turned up a notch’ compared to the Sony a7R IV. And, in spite of looking pretty similar to the Nikon Z7 II at first glance, the Sony holds on to fine detail much more effectively. Despite the high degree of sharpening, the a1 does not suffer from the overshoot at edges that you can see in images from the Nikon.

All of the options here output what we would call pleasing color, with the Sony exhibiting especially rich yellows. Compared to the Sony a7R IV, it looks like the a1 offers a number of improvements, from these richer yellows to far less magenta-tainted blues, warmer greens and slightly less muted caucasian skin tones (similar to what we saw with the Sony a7S III). Reds appear to have taken a slight dip in saturation and don’t appear as Canon-esque as they did with the a7R IV.

At higher ISO values, the Sony a1 unfortunately exhibits a fair bit of color bleed, with the Nikon putting up the strongest showing here by far. All cameras leave behind a degree of luminance noise, and honestly, all do a good job of holding on to low-contrast detail though the Canon and Nikon fall behind the other options here somewhat. Sony’s own a7R IV looks to hold on to just fractionally more detail at these settings than the a1, which becomes a little more apparent when all are viewed at a common size, but it does so at the expense of more luminance noise. With the a1, Sony chose to strike a slightly different balance, sacrificing a bit of fine detail for reduced luminance noise.

Compared to its professional peers, the a1 retains more detail at the highest ISOs than the Nikon D5 and Canon EOS-1D X III, no doubt helped by its resolution, but it does so at a slight cost of increased luminance noise and color blotches.

Raw Dynamic Range

The a1 is Sony’s third camera to utilize a full-frame stacked CMOS sensor. Its first, the a9, traded off low ISO dynamic range for sensor read speed, with the a9 II improving matters by a little over 1/2 EV at its base ISO. But as we’ll see below, the a1 brings an even greater improvement in low ISO dynamic range despite even faster sensor scan rates than either a9 model (or indeed any other consumer camera we’ve tested).

Our Exposure Latitude test does what you might be temped to do in bright light: reduce the exposure to capture additional highlights, then brighten the shadows. Even after a 6 EV push of an ISO 100 Raw file shot on the a1, noise levels remain modest in shadows, and are comparable to – albeit ever so slightly behind – the class-leading a7R IV:

Compared to its professional-oriented peers, the a1 turns in class-leading performance, with the lowest noise levels and greatest detail compared the Nikon D5, Sony’s own a9 II, and the Canon 1D X III. It’s worth noting that the Canon has similarly low noise levels in shadows after extreme pushes, but this is only made possible thanks to noise reduction in Raw which comes at the cost of detail. Switching the a1 to e-shutter mode shows only the slightest increase in noise in the deepest shadows: small enough that it’ll be irrelevant to most photographers.

Next, we take a look at ISO invariance. Our ISO invariance test looks at images shot with the same exposure settings but different ISO settings. This lets us see how much electronic (read) noise is present, that can be overcome using amplification.

At first glance, the sensor in the a1 does not appear ISO invariant, but this is due to its dual gain design. In the crops above, the noise levels of the ISO 100 and 400 shots pushed +6 and +4 EV appear similar, while the noise levels of the ISO 800 and 6400 shots pushed +3 and 0 EV appear similar. The a1 essentially has two ISO invariant ranges, between 100 and 400, and 500 upward, as ISO 500 is the camera’s second ‘native’ ISO where each pixel switches to its high conversion gain mode for better low light performance.

This means that in dim conditions, you can use the shutter speed and aperture settings of a high ISO exposure, but keep the camera set to ISO 500. By the time you brighten up the shot in post, the image won’t be noticeably noisier than it would be if you had shot natively at a higher ISO, but you’ll have saved many stops of highlight information. Similarly, in brighter conditions where fast shutter speeds might require ISOs above 100 but below 500, you can use the exposure associated with the higher ISO, but keep the camera set to ISO 100 to retain highlights. Think sports or your kids running against the backdrop of a sunset where the action requires at least 1/500s shutter speed. You may easily be bumping up against ISO 400 and clipping those skies to white, but you needn’t do so if you retain the shutter speed and aperture associated with the higher ISO but then dial the ISO back to 100 to keep the highlights from clipping.

The fully electronic shutter mode again only shows a tiny increase in noise in the deepest shadows at the lowest ISOs, and any differences in performance disappear at ISOs above 200, where amplification overcomes any extra read noise accompanying e-shutter mode.