Raw Dynamic Range

Exposure Latitude

In this test we look to see how tolerant of pushing exposure the a6300's Raw files are. We've done this by exposing our scene with increasingly lower exposures, then pushed them back to the correct brightness using Adobe Camera Raw. Examining what happens in the shadows allows you to assess the exposure latitude (essentially the dynamic range) of the Raw files.

Because the changes in this test noise are primarily caused by shot noise and this is mainly determined by the amount of light the camera has had access to, the results are only directly comparable between cameras of the same sensor size. However, this will also be the case in real-world shooting if you're limited by what shutter speed you can keep steady, so this test gives you an idea of the amount of processing latitude different formats give.

The Sony shows a touch more noise than the D7200 after a shadow push, suggesting its files are slightly less malleable than the Nikon's. That said, the D7200 is a class-leader in this regard among APS-C cameras, so this is a very good result. In fact, this performance still leaves it a little ahead of the Canon EOS 80D, despite the improvements Canon has made in this area. It's a little step forward from the Sony a6000, probably at the very least due to true 14-bit readout (the a6000 was limited to 12-bit). However, engaging fully electronic shutter, which drops readout to 12-bit, knocks the result back a bit, nearer to a6000 levels.

One thing worth noting is that the a6300, like most Sony cameras, will drop to 12-bit readout in continuous shooting mode, or in bracketing modes, or if you engage long exposure noise reduction (dark frame subtraction for long exposures). Hence, the small cost in latitude, or dynamic range, we noted above in E-shutter mode carries over to these shooting modes as well.

ISO Invariance

A camera with a very low noise floor is able to capture a large amount of dynamic range, since it add very little noise to the detail captured in the shadow regions of the image. This has an interesting implication: it minimizes the need to amplify the sensor's signal in order to keep it above that noise floor (which is what ISO amplification conventionally does). This provides an alternate way of working in situations that would traditionally demand higher ISO settings.

Here we've done something that may seem counter-intuitive: we've used the same aperture and shutter speed at different ISO settings to see how much difference there is between shooting at a particular ISO setting (and using hardware amplification) vs. digitally correcting the brightness, later. This has the advantage that all the shots should exhibit the same shot noise and any differences must have been contributed by the camera's circuitry.

In standard shutter mode, the camera is close to being ISO invariant (as, for instance, the D7200 is), suggesting it's adding very little noise to its images. This opens up the option of keeping ISO down in low light (while choosing suitably fast shutter speeds), to protect highlight detail and give yourself more processing flexibility.

This is a step forward from the a6000, which had slightly less flexible files. The effects of Sony's lossy compression also make an appearance, meaning the files are less flexible than some of its rivals'.

In this test you can more clearly see the impact of switching to the silent, fully electronic shutter mode, again likely due to the drop from 14-bit to 12-bit readout. For most shooting, you won't see this difference but it's worth disengaging if you're shooting a high-contrast scene where you might want to lift or balance the shadows (or apply a high level of the camera's built-in JPEG dynamic range feature, DRO). Since there's no significant sharpness benefit to using full e-shutter, we'd leave the camera in electronic first curtain mode unless we really needed the camera to be quieter.