Raw Dynamic Range

Exposure Latitude

In this test we look to see how tolerant of pushing exposure the G7'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 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, in real-world shooting situations you may well be limited by what shutter speed you can use, so this test gives you an idea of the amount of processing latitude different formats give.

The G7 shows very similar amounts of noise to the Olympus OM-D E-M5 II all the way up to a 5EV push (if you can overlook the differences in brightness and tint that probably relate to Adobe Camera Raw calibration). This suggests the G7 will offer a good level of processing flexibility in terms of pulling detail out of the shadows in high dynamic range images.

This result is some way behind the Nikon D5500, which produces slightly cleaner results at every given shutter speed - meaning more flexible Raws. But the little Panasonic's files are actually more flexible than those of the Canon EOS 750D/Rebel T6i, which shows extensive shadow noise when shot a similar shutter speed (The Canon may have captured a little more highlight detail, thanks to its lower base ISO, but it is likely to be less than 1EV, so it's fairest to compare the images shot at the same shutter speed).

However, the bad news is that there is visble shake in the G7's output, especially around 1/160th of a second. This isn't present in the Olympus (which was shot using electronic first-curtain shutter). The shake can be eliminated by using the G7's (fully) electronic shutter. However, while this eliminated the shake, it also adds noise, which in turn reduces the degree to which you can adjust the files before the detail is overwhelmed. Unfortunately, an electronic first-curtain option, which in most cameras that offer it eliminates shake while not introducing additional noise, is not available.

The slight softness induced by shutter shock may only be visible in side-by-side comparison with shots that don't exhibit it, but it's worth being aware that it can reduce sharpness at certain shutter speeds and there is a way of protecting against it, but this has its own costs. At which point, in shooting situations where image quality is critical, you need to decide which price you'd rather pay.

ISO Invariance

A camera with high (base ISO) dynamic range has a very low noise floor, which has an interesting implication: the low noise floor can reduce the need to amplify the sensor's signal in order to keep it above that noise floor. This can afford you benefits in situations conventionally demanding 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) or digitally correcting the brightness, later.

As you can see, there's virtually no difference in noise performance between shooting at ISO 1600 and shooting the same exposure at ISO 200 and brightening. This means that, when in mechanical shutter mode, you are likely to be able to under-expose ISO 200 by 3EV and brighten the Raw file later, rather than shooting at ISO 1600. Why would you do this? Because using less hardware amplification means that you don't end up over-amplifying the top 3EV of highlight data: so you retain highlight data but with essentially no noise cost. This is essentially the same outcome as the Olympus OM-D E-M5 II.

This isn't true in Electronic Shutter mode, though. Just as the additional noise started to creep into the exposure latitude images. A 2EV push of a file starts to exhibit more noise than natively shooting at ISO 1600 and after a 3EV push it's really obvious. Given how much of your image is likely to be made up of dark tones in the situations in which you might use high ISO settings, this difference is likely to be very obvious.