Image Quality

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.

Key takeaways:

  • The a7 III is among the best low-light cameras on the market
  • Great sharpness, at the expense of some moiré patterns
  • Excellent dynamic range
  • Best JPEG noise reduction and sharpening on the market
  • Color is improving, particularly skintones

For a closer look at these, scroll on and check out our studio scene for yourself.


Raw capture

Raw detail capture is about as good as we can expect given the 24MP sensor, with plenty of color aliasing on the white-on-black text. Raw files are also sharper than the Sony a9, which uses a stronger AA filter in both directions. Elsewhere in the scene, the a7 III exhibits plenty of detail and aliasing to go around.

At higher ISO values, the a7 III pulls ahead of the D750, and is up there with the best performing low light cameras in terms of deep shadow noise, which is indicative of increased dynamic range at those ISO values. This is in part due to the a7 III's dual gain architecture, which switches the sensor to a higher sensitivity mode at the pixel level; check out the jump in dynamic range at ISO 640 when compared to the D750 in Bill Claff's quantitative measurements. The greater high ISO dynamic range gives the a7 III, and most recent Sony sensors, a leg up in noise performance of pushed high ISO shadows compared to more traditional sensors.

Notably, the a7 III far outperforms its predecessor at high ISO.

JPEG

In terms of JPEG color, the red patch looks incredibly similar to the Canon EOS 6D Mark II (which itself looks very similar to the Canon EOS 5D Mark III, still one of our color benchmarks). This has a remarkable impact on skintones, which look more traditionally 'Canon-like' on the on the a7 III than Canon's own 5D Mark IV. However, greens in particular continue to show more of a blueish cast from the Sony, and the yellows skew slightly more green than we'd like to see.

When we switch over to low light and auto white balance, the scene generally keeps tones on the warm side, including greens. It's worth noting that there is an additional automatic white balance setting that keeps warm tones even warmer (first seen in Sony's a9), should you prefer.

Sony's context-sensitive noise reduction is better than ever, meaning it's probably the best on the market right now, made even more impressive by comparison to the Raw image. Even in areas of low-contrast detail, the a7 III excels. Sharpening is well-judged with no real sign of haloing on edges due to large-radius sharpening, and areas of fine detail are nicely accentuated.

Moiré

One of the more fashionable trends in digital cameras over the last several years has been the removal of the anti-aliasing (AA) filter, which traditionally sits just in front of the sensor. While Sony has included an AA filter on the a7 III, it only filters horizontal, not vertical, detail. That means overall it's relatively weak: the a9 in comparison has AA filters for both horizontal and vertical detail. This shows up as increased moiré across the test scene, more so than the a7R III, a9, or 6D II at common viewing size.

So we wondered how big a of a problem it is with one of the most moiré-prone subjects an a7 III shooter is likely to encounter - a wedding dress.

Sony FE 50mm F1.4 ZA | ISO 100 | 1/60 sec | F5.6
Flash off to camera left, processed in Adobe Camera Raw using the Adobe Standard profile

We did three trial sets of images, from full length to close-up, and this is among the worst in terms of moiré that we came up with. There is some visible near the bottom of the right side of the dress, and in the subject's hair.

Bottom left of dress Hair

So, despite the appearances of our studio scene, we were hard-pressed to get moiré to be a huge problem in the real world. Interestingly, using the Sony 'camera standard' or other profiles increased the appearance of moiré, so we'd stick to using Adobe's profiles for now. We also have to admit that in Adobe Camera Raw, the 'Moiré Reduction' local brush does a pretty incredible job of removing artifacts without damaging image quality.

In any case, if you do find this level of moiré to be an issue for your style of shooting, the a7R III is a better option and proves more resistant to moiré patterns than its lower resolution sibling.

Flare and striping artifacts

When we published our original Sony a7 III sample gallery, we and our readers had some concern over odd striping artifacts viewable in some images shot with the FE 85/1.8.

It's known as 'PDAF striping' and it's not limited to a single camera, or even a single brand. It's likely due to light reflections off the metal masks of on-sensor phase-detect pixels. Masked pixels, as opposed to a split dual-pixel design that obviates the need for metal masks, is to the best of our knowledge a design choice: the approach enables high performance AF even during 10 to 20 fps bursts.1 The unfortunate side effect is the potential - albeit rare - for single pixel stripes in transitions from blown areas to darker ones with certain lenses in toughly backlit scenes.

This isn't an issue unique to the a7 III: many other Sony cameras have it (like the a7R II/III, a9, R100 V), as do other cameras using masked pixels for on-sensor PDAF (like Olympus). The occurrence of this 'striping' is very hard to predict, rarely occurring with some lenses but readily occurring with others, under the right conditions to induce them. For example, we weren't able to reproduce visibly distracting striping with the Sony FE 35/1.4 (left), but did so quite easily with an adapted Canon 35L (right).

Striping is barely visible with the Sony FE 35/1.4

Striping is readily visible in the toddler's face and hair with the Canon 35/1.4L II. There are tools to easily and convincingly remove most of the artifacts (see here).

We set up a stress test in our studio (see setup here) and checked many lenses. We haven't found a pattern that allows one to predict which lens will be problematic, but we were able to differentiate lenses that produced a strong pattern (85/1.8, Canon 35L II, Canon 85L II), a mild one (50/1.4 GM, 85/1.4, 70-200/2.8 GM), or none at all (35/1.4, Rokinon 35/2.8, 55/1.8, 24-105/4, 70-200/4). Striping wasn't very dependent on aperture.

The good news is there are workarounds already available, and others in development. We dive into this in our coverage but, briefly, Prof. Hank Dietz at the Univ. of Kentucky has independently developed his own fix that returns you a compressed Raw .ARW file to work with here. Furthermore, our own DPR forum member pippo27 has implemented a fix in the Raw processing pipeline of the open-source RawTherapee Raw converter, based on an understanding of the exact locations of the masked PDAF pixels.2 It's already available in development versions you can download here, and will be included in the next major release. There's even a Photoshop fix developed by DPR forum member Magnar W, if you're past the Raw development stage or have a problematic JPEG.

The take-home? 'Striping' is an unfortunate consequence of the high speed, high accuracy AF that on-sensor masked-pixel PDAF affords us, but in the rare cases it rears its ugly head, you'll likely have a workaround. That said, workarounds are workarounds that typically come at some cost - like slowing down workflow. There's no 'official fix' yet from Sony, so depending on your photography style and lens collection, 'striping' may or may not be a legitimate concern.

Silent shutter artifacts

One of the great advantages to the the latest generations of mirrorless cameras is their performance when shooting silently, using a fully electronic shutter. Especially handy at, say, a wedding or press conference, we did note some banding and other artifacts in some isolated situations with the a7 III.

The LED lighting in this particular restaurant was very susceptible to this 'banding' effect.

In addition, while Sony's a9 sports camera is designed to be used with its fully electronic shutter all the time, even in situations with fast-moving subjects, the a7 III's electronic shutter isn't quite a match in terms of how quickly it can read out an image (nor would we expect it to be). The a9 can read out its sensor at around 1/160 sec, compared to the roughly 1/18 sec we've measured on the a7 III. It's twice as fast (~1/34s) in JPEG or continuous compressed Raw silent shooting, which should help a bit with rolling shutter, but banding in artificial light might still be an issue.

Here's what that looks like when using the electronic shutter to photograph a dancer in mid-air:

Slightly squashed Slightly un-squashed

Because the electronic shutter takes more time to read out than the mechanical shutter, you can get 'squashing' or 'stretching' with subjects moving the vertical direction, or 'leaning' in the horizontal direction.

But in any case, that the mechanical shutter on the a7 III now operates at up to 10fps negates much the need for a silent shutter for action shooting in most situations, with sports such as golf being notable exceptions.

I photographed this couple in the Amazon Biospheres using the silent shutter, to as to avoid disturbing other visitors. Despite the mix of ambient and artificial lighting, I didn't find any artifacts to speak of.
Sony FE 85mm F1.8 | ISO 2000 | 1/400 sec | F4

For the above image, I photographed this couple inside of Amazon's biospheres, and opted to use the electronic shutter throughout the shoot in the interest of avoiding disturbing others. Despite a wide variety of mixed lighting, I didn't encounter any banding or other issues to speak of.


1Both Sony and Canon executives have hinted to us the higher performance of the masked approach, and the computational burden of the dual-pixel approach, respectively.

2Thanks to extensive investigations led by Jim Kasson, Bill Claff and forum member Horshack.