Introduction and features
With G, GM, GF, GH and GX lines, Panasonic’s G series of compact system cameras can get a little confusing. The GX models have a flatter, more rectangular shape than the SLR-like G and GH ranges, and they’re more advanced than the GF and GM cameras. The latest introduction, the GX8, is an upgrade from the very successful GX7, which continues in the line for the foreseeable future.
Naturally, Panasonic is hoping the GX8 will be as popular with enthusiast photographers as the GX7 was, and it makes a good start by featuring the company’s first Four Thirds type sensor, with a pixel count over 16 million. In fact it has an effective pixel count of 20.3 million, and Panasonic claims this enables the camera to produce the highest image quality from any G-series camera, beating both the flagship GH4 and the recently released G7.
To complement the 25% increase in pixel count, which Panasonic claims brings a 15% improvement in detail resolution as well as better signal to noise ratio and dynamic range, the GX8 has a new processing engine. However this is new to the GX line rather than to the G-series, and it’s the same engine as in the GH4 and G7.
This enables a native sensitivity range of ISO 200-25,600, with an expansion setting of ISO 100, as well as a top continuous shooting rate of 8fps at full resolution. This frame rate is available in single autofocus mode; if you want to shoot full-resolution images with continuous autofocus the rate drops to 6fps.
There’s also a new 2,360,000-dot OLED electronic viewfinder (EVF) which is much bigger than we’ve seen on previous Micro Four Thirds cameras. It offers 1.54x magnification, which is equivalent to 0.77x in 35mm format – the same as the Fuji X-T1. Panasonic claims there’s less fringing and blurring in its finder than Fuji’s. As on the GX7, the GX8’s EVF can be tilted up for easier viewing from above.
In a change from the GX7, the GX8 has an OLED screen with 1,040,000 dots. Also, rather than being mounted on a tiltable bracket, it has a vari-angle hinge, which makes portrait and landscape-orientated image composition easier at high or low angles. As you’d expect from Panasonic, the screen is touch-sensitive.
Panasonic has also introduced a new Dual Image Stabilisation System, which combines lens and sensor-based stabilisation to reduce image blur when you’re hand-holding the camera. The lens applies 2-axis stabilisation, while the body applies 4-axis compensation. Apart from in 4K mode, there’s 5-axis stabilisation in video mode.
Being a Panasonic camera, the GX8 can record 4K videos (as well as Full-HD), and has 4K Photo mode with three shooting options: 4K Burst Shooting, 4K Burst (Start/Stop) and 4K Pre-burst, which are designed to record footage from which 8Mp still images can be extracted.
In 4K Burst Shooting mode the camera records 4K footage for as long as the shutter release is held down, and in 4K Burst (Start/Stop) mode recording is started with a press of the shutter release and is stopped by a second press.
In 4K Pre-burst mode the camera starts scanning as soon as the mode is activated, but only the 30 images immediately before and after the shutter button is pressed are recorded, giving 60 shots in total.
In addition to these three modes, a new focus-shifting 4K Photo mode is planned, and will be introduced with a firmware upgrade. In this mode the camera shoots a sequence of 10 images at 30fps, each with a different focus distance – you can then select where you want the focus to be post-capture.
It’s possible that Panasonic may also create a focus-stacking option to enable the creation of images that are sharp from front to back.
As with the G7, the 4K Photo modes can be used when shooting in program, aperture priority, shutter priority and manual exposure mode, so it’s possible to take full control over exposure if you want.
Images can be shared directly from the GX8 using the built-in Wi-Fi, which can show a QR code for making the first-time connection so that you don’t have to enter a password. There’s also NFC (near field communication) technology for making fast connections to NFC-enabled devices.
Build and handling
As mentioned, the GX8 has a flatter, more rectangular shape than the G7 and GH4. Nevertheless it has a deep, effective front grip and a shallow thumb-ridge that gives just enough purchase – though it wouldn’t hurt if this was a little more pronounced and more ergonomically shaped.
While I find there’s enough space to accommodate my thumb on the back of the camera, those with bigger hands may find that their thumb feels a little confined, and may accidentally press the Quick Menu or Display buttons from time to time.
That said, its magnesium alloy body gives the GX8 a higher-quality feel than the G7, and it’s also splash- and dust-proof, so it can be used in more inclement conditions. The new camera is also noticeably larger than the GX7 in every dimension, but it looks a little cleaner and has a bigger front grip.
Like the GX7, the GX8 has a dual-dial control system, but the GX8’s dials are bigger and/or easier to reach. The front dial, for instance, which surrounds the shutter release, is easier to reach because the shutter button has been moved forwards to the top of the grip, while the rear dial is larger, and located on the top plate within striking distance of the thumb rest.
Like the GX7, the GX8 has a mode dial on the top plate for selecting the exposure mode, but this has now shifted from the far right towards the middle, and it sits above a new exposure compensation dial that has settings running from -3EV to +3EV in 1/3EV steps. As well as making it very quick and easy to adjust exposure, having a dedicated dial enables you to check the setting even before the camera is turned on; I was able to adjust exposure compensation using my thumb on the dial while looking in the viewfinder.
After shooting with the Panasonic G7, I found that I missed its drive mode dial on the GX8. Amongst other things, on the G7 this offers a quick way of switching between single shooting, continuous shooting and 4K Photo mode. While 4K Photo mode is useful for shooting developing action, it only generates 8Mp JPEGs, which have to be extracted from the video footage. Consequently, there’s good reason to want to switch back to 20Mp raw file shooting quickly.
On the GX8 there are several ways of accessing the various shooting options. The most obvious are via the drive mode button or the Quick Menu – which is accessed by pressing the Q button. By default there’s an on-screen function button to access 4K Photo mode, and it’s possible to customise a physical button to reach the options, but neither is quite as quick as flicking a dial round.
Having a vari-angle screen is a big improvement on a tilting unit – it’s much more versatile, enabling you to compose low- or high-level shots in landscape or portrait format, and to make the most of the facility to adjust settings using the touchscreen.
One issue I encountered when shooting at a high or low angle, however, was that it can be hard to locate some of the buttons on the back of the camera by feel alone. The Review, Display, Delete and navigation buttons all protrude clear of the camera body, making them pretty easy to find, but the Quick Menu and lower Function buttons are flush with the body, which makes them harder to locate. There’s also no on-screen option to bring up either the Quick or main Menus.
I’m a fan of Panasonic’s Touch Pad AF system, which enables you to set the AF point using the screen while looking into the viewfinder. However, when using it on the GX8 there were a frustrating number of occasions when the AF point started to resize rather than move to where I wanted it to be – it would be nice to be able to lock-off the resizing.
When shooting in landscape format, left eye users may find that they sometimes shift the AF point with their nose when using Touch Pad AF. I found it only happened occasionally, as the GX8’s EVF protrudes quite some way beyond the screen, and if necessary the viewfinder can be tilted upwards a little to prevent your nose from touching the screen. It can also be an issue when shooting in upright format, as the top of the screen is within touching distance of your nose.
The new electronic viewfinder (EVF) is also a step up, providing a clear view with no visible texture or noise, and the image it displays is a good match with the captured shot. It’s also a big device, and I found that when shooting upright images I had to consciously look up and down towards the outer edges to check composition – but that’s a problem I don’t mind having.
In addition, the viewfinder’s refresh rate seems high, and I was able to follow the movement of body boarders and surfers as they zipped along some stormy waves.
There’s also a sensor which activates the EVF and turns off the screen when the camera is held to your eye. As usual this can be a pain when you’re adjusting settings or manipulating the camera into position, as your hand turns off the screen as it passes near the viewfinder, but there’s a handy button that can be used to override the sensor and keep the screen on.
Although an electronic level can be useful, the GX8’s has quite a wide margin of error, which means it’s possible to produce images that look significantly tilted when the level indicates that the camera is straight.
While it’s aimed at experienced and enthusiast photographers, the GX8’s controls and menus are arranged well, and it’s relatively easy to get to grips with using it. The build is reassuring and the camera responds quickly to adjustments, whether it’s a tap on the screen or a press of a button.
It’s helpful that the Quick Menu is customisable, but it would be nice if there was a customisable main menu screen as well.
Because it has an electronic viewfinder that’s capable of previewing images with the settings applied, as well as reviewing shots, browsing through my shots from the GX8 doesn’t bring any major surprises. On the whole the camera produces pleasant colours and good exposures.
As it’s the first Micro Four Thirds camera to offer a pixel count of greater than 16 million, there’s a lot of interest in how much detail the GX8 can capture, and how well noise is controlled – it’s good news on both counts.
With the right lens the camera is capable of capturing an impressive level of detail. In our lab it matched the 24Mp Sony Alpha A6000 for detail at the lowest sensitivity setting, and its JPEGs beat it for much of the range. It also compares very well with the Olympus OM-D E-M5 II, although it doesn’t have the same neat trick for increasing resolution.
The GX8 also impresses in the noise control stakes, with chroma noise only making the faintest of appearances in raw files shot at ISO 1600 when all noise reduction is turned off – you really have to look for it in images sized to 100%. Push up to ISO 3200 or 6400 and there’s naturally an increase in the level of noise in raw files, but it’s still subtle.
Meanwhile, JPEGs taken at the default settings look very good with lots of detail and a very slight smoothing of some details; at 100% raw files look a little more natural. Noise is more pronounced in raw files recorded at ISO 12,800, but there’s also a good level of detail visible.
At ISO 25,600 there’s a noticeable drop in saturation, and raw files are very noisy while JPEGs are soft, making them only suitable for use at relatively small sizes – but that’s not unusual.
Panasonic has issued firmware upgrades for some of its lenses to enable them to work with the GX8’s hybrid stabilization system. When shooting at the telephoto end of the Panasonic G X Vario 35-100mm f/2.8 lens, which with the Four Thirds type sensor has an effective focal length range of 70-200mm, I found that on a regular basis I was able to get images that look sharp at 100% using a shutter speed of 1/10 sec; even some shots taken at 1/8 sec were sharp.
Turning on the stabilization system also has a significant effect on the view in the viewfinder – it becomes much more stable, but there isn’t the nauseating yaw that can occur with some older systems. It also has a positive impact upon video footage; you can’t hand-hold the camera while walking and expect super-smooth movies, but the minor tremor and shake that we normally expect is gone.
Panasonic’s general purpose Multi metering system has impressed me in the past, and this continues with the system in the GX8. There were a few occasions when I needed to use the exposure compensation dial during my time with the camera, but none of these were situations in which I wouldn’t expect to. In many instances the camera manages to cope with quite large bright areas in the frame without dramatically underexposing the rest of the scene.
In some images the sky looks burned out, but it’s possible to retrieve quite a bit of detail from the raw file to create a better-looking end result. It’s not just the raw files that have good dynamic range though – the JPEGs are also decent.
With very high-contrast scenes the dynamic range enhancing system, iDynamic, is worth using to boost the tonal range of JPEGs. Even when this is set to its highest value it produces natural-looking, rather than overtly HDR, results.
The effect isn’t always predictable, but it often has more noticeable effect on shadows than highlights, brightening the darker areas to bring out detail. Using it also often triggers the camera to set a lower exposure to capture more detail in the highlights, which means it has an impact upon raw files as well as JPEGs.
Using the automatic white balance setting and Standard Photo Style usually produces good results from the GX8, although if you want a little more warmth in overcast conditions it’s worth switching to the Sunny setting. As is often the case, the Cloudy and Shade settings warm things a little too much.
The Standard Photo Style is a good all-rounder, but the other options – Vivid, Natural, Monochrome, Scenery and Portrait – are also worth exploring. Each can be adjusted to taste, and there’s an option to save your own custom Photo Style.
Although I would usually convert raw files to mono in software, I found it was possible to produce some very nice in-camera black and white and toned images using the Monochrome setting.
There’s also a collection of 22 filter effects that can be applied to JPEG files, with simultaneous raw files if you select the option. As usual these effects will appeal to some tastes and not others, but some can produce excellent results in the right situation, so it’s worth experimenting with them. The Sun filter, for example, can add a colour cast along with a large white patch to simulate flare, and while it doesn’t suit every scene there are times when it works very well.
Panasonic claims that its DFD (Depth from Defocus) autofocusing technology, first seen in the GH4, has a response time of 0.07 seconds in the GX8, and that there’s a 200% improvement in AF tracking performance. I can’t verify the figures, but I found the GX8 capable of keeping pace with moving subjects when the active AF point is held in the right place, and the tracking system can follow fairly fast-moving subjects.
I used the GX7 in the photographer’s pit at Fairport Convention’s Cropredy Festival 2013, and I was able to do the same with the GX8 this year. The newer camera’s AF system was able to cope much better when light levels fell and the stage lights provided all the illumination, making the camera much more versatile than the previous model.
Lab tests: Resolution
We’ve carried out lab tests on the Panasonic GX8 across its full ISO range for resolution, noise (including signal to noise ratio) and dynamic range. We test the JPEGs shot by the camera, but we also check the performance with raw files. Most enthusiasts and pros prefer to shoot raw, and the results can often be quite different.
Panasonic GX8 resolution charts
We test camera resolution using an industry-standard ISO test chart that allows precise visual comparisons. This gives us numerical values for resolution in line widths/picture height, and you can see how the Panasonic GX8 compares with its rivals in the charts below.
JPEG resolution analysis: The GX8’s resolution scores compare favourably with those from the Olympus OM-D E-M5 II, Fuji X-T10 and Sony Alpha A6000 up to ISO 6,400.
Raw (converted to TIFF) resolution analysis: While scores at low sensitivity settings are good, they drop off as sensitivity rises and achieve a lower score than the JPEGs, although this isn’t really reflected in real-world images. However, the files are subject to a standard conversion using the supplied Silkypix software, with all noise reduction turned off. A bespoke conversion, made to suit the image, is likely to produce better results.
Sample Panasonic GX8 resolution charts
This is the chart we use for testing camera resolution. The key area is just to the right of centre, where a series of converging lines indicates the point at which the camera can no longer resolve them individually. We shoot this chart at all of the camera’s ISO settings, and here are two samples at ISO 200 and ISO 6400.
Lab tests: Dynamic range
Dynamic range is a measure of the range of tones the sensor can capture. Cameras with low dynamic range will often show ‘blown’ highlights or blocked-in shadows. This test is carried out in controlled conditions using DxO hardware and analysis tools.
Dynamic range is measured in exposure values (EV). The higher the number the wider the range of brightness levels the camera can capture. This falls off with increasing ISO settings because the camera is having to amplify a weaker signal. Raw files capture a higher dynamic range because the image data is unprocessed.
Panasonic GX8 dynamic range charts
JPEG dynamic range analysis: The GX8 produces JPEGs that have a consistent tonal range throughout much of its sensitivity range, with good detail in shadows and highlights.
Raw (converted to TIFF) dynamic range analysis: The GX8’s high dynamic range score continues into the upper sensitivity values, confirming our findings that raw files have a good range of tones.
Lab tests: Signal to noise ratio
This is a test of the camera’s noise levels. The higher the signal to noise ratio, the greater the difference in strength between the real image data and random background noise, so the ‘cleaner’ the image will look. The higher the signal to noise ratio, the better.
Panasonic GX8 signal to noise ratio charts
JPEG signal to noise ratio analysis: These scores are consistent with the GX8’s ability to capture a good level of detail while controlling noise well for the majority of the sensitivity range.
Raw (converted to TIFF) signal to noise ratio analysis: This is an especially strong set of results from the GX8, which indicate that raw files don’t have a huge level of noise.
Sample Panasonic GX8 ISO test results
The signal to noise ratio charts use laboratory test equipment, but we also shoot a real-world scene to get a visual indication of the camera’s noise levels across the ISO range. The right side of the scene is darkened deliberately because this makes noise more obvious.
Panasonic has been using a 16Mp sensor for a long time, so the jump up to 20Mp is a major step, and it has the desired impact upon detail resolution. What’s more, this has been achieved while keeping noise in check, with images looking very good when sensitivity is set to ISO 100-6,400.
The improved stabilization system is also very good, enabling sharp images to be captured at shutter speeds that would normally rule out hand-holding the camera. In addition it makes the image in the viewfinder much more stable, and video footage smoother.
While it is possible to make A3 prints from 8Mp files shot in the 4K modes, many photographers will feel uncomfortable about buying a 20Mp camera and shooting at this lower resolution, even if it is at 30fps; however, it brings considerable satisfaction when you realise that you’ve caught a fleeting moment. It will be interesting to see how Panasonic implements the focus-shifting option.
It’s clear that the GX8’s AF system has made a step forward from the GX7’s. It’s fast and effective in a wide range of lighting conditions, including low light, and keeps up well with moving subjects.
The GX8 has an extensive feature set, and a pleasantly solid build that should appeal to enthusiast photographers. It’s also very flexible to shoot with, as it has an excellent viewfinder than can be tipped through 90 degrees to make it easier to see and a vari-angle screen that’s useful for composing images in either orientation.
It’s also possible to control the camera using either the touchscreen or the well-appointed collection of buttons and dials, and the exposure compensation dial is a welcome addition to the top plate.
Panasonic’s 4K Photo mode is a fun feature that makes capturing fleeting moments very easy, but it seems quite a wrench to drop from 20 million pixels to just 8Mp, even if you can make decent A3 prints.
Many photographers will also appreciate the image stabilization system, which does a great job of correcting for the little shakes and wobbles that can blur images taken in low light or at the telephoto end of a lens.
The GX8 is quite a bit bigger than most other Micro Four Thirds cameras, especially the popular Olympus OM-D E-M10. While some may appreciate its larger dimensions, this doesn’t translate into much more space for your hand on the back of the camera. In addition, some of the rear buttons are hard to locate when your eye is at the viewfinder.
The GX8 is a nice solid camera with a couple of flourishes, such as the tilting viewfinder, vari-angle touch screen and 4K Photo mode, that give it added appeal to creative and enthusiast photographers.
Given its higher pixel count, better viewfinder and high-quality vari-angle screen it could prove more popular with this market than the recently released G7, but there’s a significant step-up in price. Image quality is also very high, making the GX8 a rewarding camera to use.
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