Panasonic GX8 Field Test

Panasonic GX8 Field Test

Great design & great sensor make for a fantastic camera

by Jeremy Gray | Posted 11/17/15

Introduction

The Panasonic Lumix GX8 is Panasonic's new flagship GX-series camera and it includes many improvements over the popular GX7. Compared to the predecessor, the GX8 features a new 20.3-megapixel Four Thirds imaging sensor, improved autofocus performance and a new image processor from the Panasonic GH4 camera, a tilt-swivel screen, and 4K video. While the GX7 is still available for sale, the GX8 has a strong feature set and provides very good performance across the board. 

Key Features

• 20.3-megapixel Digital Live MOS Four Thirds sensor
• Tilting OLED EVF and 3" OLED tilt-swivel rear display
• 49-point contrast-detect autofocus system with 0.07s focus acquisition time and new tracking algorithms
• Dual image stabilization
• 1/8000s mechanical shutter speed and 1/16000s electronic shutter speed
• Up to 10fps continuous shooting using the electronic shutter
• Native ISO range of 200-25,600 (expandable to 100-25,600)
• 4K video at up to 30fps
• 4K photo (8-megapixel images captured at up to 30fps)
• Built-in Wi-Fi and NFC

A well-built camera body with many easy-to-use controls

Despite using a Four Thirds sensor, the GX8 is a decent-sized camera. Weighing in at 17.2 ounces (487 grams) with the battery inserted, the GX8 is quite a bit larger than the GX7, but this extra size makes the camera more comfortable to use for extended periods of time, in my opinion, and also affords space for more manual controls and dials. With its deep front grip and numerous physical controls, the GX8 feels excellent to hold and use. The GX8 looks great, too, with styling reminiscent of old rangefinder cameras.

Underneath the rotating mode dial on the top of the camera is the exposure compensation dial. (Editor's Note: Panasonic has since flipped the values on the EV dial, placing positive exposure compensation values toward the front of the camera.) I really like this stacked dial design as it makes efficient use of the space on the camera without sacrificing usability. Further to the right on the top of the camera is a rear dial, the shutter release, and surrounding the shutter release is a front dial. Both the rear and front dials rotate well and provide good tactile feedback. There are also a couple of function buttons on top of the camera (in addition to the ones on the front and back).

The back of the camera is dominated by the GX8's fully-articulating 3" OLED touchscreen. The display looks really nice, even in bright light, and the touchscreen features work well. The articulation range of the display is very impressive, and it's quick and simple to get the display exactly where you want it. The swiveling mechanism itself works well, but it doesn't feel very strong and the display is slightly loose when moving it around. The OLED electronic viewfinder on the GX8 also tilts, which is unusual, but it certainly provides extra utility. To the right of the rear display are a standard variety of easy to reach buttons, including a particularly useful Quick Menu (Q. Menu) button.

Overall, while the GX8 might be a bit large for a camera with a Micro Four Thirds sensor, it handles very well. There is a wealth of control provided to the user and everything is well-placed and designed. The fully-articulating touchscreen is a highlight on an already great camera body. The body itself is also dust- and splash-resistant.

New 20.3-megapixel sensor captures excellent images

The GX8's new 20.3-megapixel Live MOS sensor produces great images. The sensor is the highest-resolution Four Thirds sensor available right now and also provides noise and dynamic range improvements over the GX7's 16-megapixel image sensor. Along with the higher resolution sensor, the GX8 includes a new Aperture Filter that uses more natural edge processing to intelligently sharpen in-focus areas of an image while sharpening smoother, out of focus areas less. There is also diffraction compensation to limit the softening effect of capturing images at small apertures. The GX8 also includes an improved image processor, utilizing the same Venus Engine image processor as Panasonic's flagship GH4 camera. With the improved image processor and image sensor, the GX8 is reported to have better color processing than the GX7 and dynamic range that is about 1/3 stop better than the GX7.

The GX8, with its many features, captures really nice images. Image files contain good detail, smooth transitions, accurate colors, and plenty of freedom to adjust images and maintain good results. After a bit of sharpening and processing, RAW files look very nice. I was also able to push the shadows a fair bit with RAW files and reduce highlights as needed. In addition to Photo Styles like Vivid, Natural, Portrait, and more, the GX8 allows the user to adjust the brightness of dark and bright areas in an image using preset or custom curves, i. Dynamic (automatically adjusts brightness and contrast), and i. Resolution (automatically adjusts sharpness and resolution). These features can certainly improve image quality in certain situations.

The GX8 shines out in the field

With its wealth of controls and great performance, the GX8 handles very well out in the field. Adjusting important shooting settings is easy, and I found that using the touchscreen was quicker for selecting an AF area. When shooting in partially- or fully-automatic shooting modes, the GX8 performs well and provides consistently good results. The GX8 has a new dual image stabilization system as well. While the lenses I used with the GX8 include optical image stabilization, the GX8 itself also has in-body stabilization that is achieved via sensor shift. The new stabilization works really well and allows for sharp images to be captured at impressively slow shutter speeds.

While I touched on how the camera body handled earlier, it is worth noting again that everything feels great when using the GX8. The tilting EVF and the tilt-swivel rear display are very useful out in the field. The EVF itself works really well and provides 0.77x magnification compared to the 0.70x magnification of the EVF on the GX7. Further, the amount of highly-customizable function buttons is impressive. The only handling aspect of the camera that I don't like is that it takes too many steps to move an AF area or point using the camera's buttons (using the touchscreen works fine provided you have the camera stabilized or don't mind pulling it away from your face to interact with the display). With that said, having touch enabled did create some issues for me at times. With the display set to automatically switch between the EVF and the rear display, there were numerous instances when the camera would switch to the display despite me looking through the EVF and then my face would touch the display and move the AF point around. This took a little getting used to.

The GX8 offers multi, center-weighted, and spot metering options, with spot metering thankfully not locked to the center of the frame. Being able to move the spot around the frame is convenient for metering. In most situations, I utilized multi metering, and the performance was good, proving to be consistent and predictable. In widely varied lighting situations, the camera had a slight tendency to overexpose when using multi metering, but with the exposure compensation dial within reach when using the camera, making any necessary exposure compensation adjustments is easy.

When using Intelligent Auto or Intelligent Auto+ (this mode allows you to adjust brightness and color yourself), the GX8 captures pleasing images. In many cases, the camera does opt for a wide aperture and faster shutter speed so if you want a smaller aperture, you will have to use aperture priority or manual shooting modes. Disappointingly, the GX8 records only JPEG files in Intelligent Auto mode, but it can record RAW files in Intelligent Auto+ mode.

There are numerous additional shooting modes on the GX8. Panorama mode is available in 8176 x 1920 and 8176 x 960 resolution options and provides decent results. The final panoramic is not very high resolution, but it can be a useful and neat feature nonetheless. There is also Creative Control mode, which allows you to select from a wide variety of filter effects, including High Dynamic Range and multiple monochrome options. The HDR option is a filter effect rather than a true HDR image, but the GX8 does offer quick exposure bracketing options via the Drive Mode button on the back of the camera. In addition, when recording only JPEG image files, a true HDR option becomes available in the menu. You can set HDR to Auto or to an amount of EV from 1 to 3. The results are pretty good and the GX8 processes the files quickly.

The GX8 has an interesting Clear Retouch feature that allows you to trace unwanted items on an image and then the camera will remove them (in a similar vein to Photoshop's Spot Healing tool). While the feature is a neat idea, it doesn't do a particularly good job except with very small items. It introduces a lot of artifacts and blocky areas to an image. The GX8 also has built-in RAW processing options. You can adjust white balance, exposure compensation, Photo Style, contrast, noise reduction, and a number of other parameters, and then process a RAW file into a JPEG with your selected settings. There is a slight delay when changing settings as the display goes black, but it is overall a smooth experience that makes editing images in-camera really easy and enjoyable. Along with the ability to crop and resize images inside the camera, you can do an impressive amount of editing and processing right on the GX8.

Quick autofocus in many situations

The GX8 uses a contrast detect autofocus system that provides quick and accurate autofocus. Panasonic reports that the GX8 can acquire focus in just 0.07s, compared to the 0.11s acquisition time of the GX7. This is due to the GX8 including the Depth from Defocus technology from the GH4 camera that provides faster autofocus performance when using Panasonic lenses.

The GX8's 49-point autofocus system can be utilized in a wide variety of ways. The GX8 has Face/Eye detection, Tracking, 49-Area, Custom Multi, 1-Area, and Pinpoint AF modes. 49-Area AF mode works well at accurately determining the subject in most situations. It is also the AF mode used in Intelligent Auto shooting mode. Custom Multi AF mode is new to the GX8 and allows you to either choose from a focus area preset such as horizontal line, vertical line, and central pattern or create your own shape. This is a very cool feature.

When using 1-Area AF mode, you can quickly move the AF area around using touch. To move the AF area around using the directional buttons, however, you have to first go into the AF menu by pressing the left directional button and then select 1-Area AF mode to be able to move the area around the frame, which takes much more time than a simple tap on the screen. By enabling direct focus in the custom menu, you can instead move the AF area around by just pressing the directional buttons, but this means that you lose the quick access to the ISO, AF, white balance, and drive menus. I found that using touch is the best way to move the AF area. The AF area covers a really large portion of the frame as well, so you can place the autofocus area pretty much wherever you need it. Pinpoint AF is similar to 1-Area AF mode except that the display zooms in on the focus area for very fine focusing, which can be very useful when working on a tripod and want to get focus on a precise spot.

The continuous autofocus performance of the GX8 is improved over the GX7. The GX8 uses new tracking algorithms that, according to Panasonic, is more than 200% better than that of the GX7. Having not used the GX7, I can't confirm that improvement, but I can say that the GX8 does a very good job with subject tracking. Once the camera has locked onto the subject, it does a good job of keeping the focus area on the subject and maintaining focus as it moves through the frame or moves towards or away from the camera. There is a slight delay, particularly in lower light, but the GX8 is often able to catch back up to the correct subject and reacquire focus.

Good low light performance, but no flash

The GX8 has a native ISO range of 200-25,600 and can expand down to ISO 100. It includes a random noise filter to make noise smoother. I found that the GX8 has great overall high ISO performance and produces very usable RAW files all the way up to and including ISO 3200. At ISO 800, noise starts to become visible when viewing image files at full resolution. However, it isn't until ISO 3200 that the visible noise becomes problematic. Even so, images look pretty good at ISO 3200 without any noise reduction applied in post-processing, appearing only slightly less sharp than images captured at ISO 1600, which itself looks only marginally noisier than images taken at ISO 800. At ISO 6400, visible color noise becomes much more apparent and a lot of fine details in the image file are lost. These issues become much more dramatic as you go up to ISO 25,600, which is not an ISO speed that I would ever use with the GX8. Personally, I would like to capture images at ISO 1600 or less for large prints, but I think that ISO 3200 is very capable for small prints and sharing on the web.

The GX8 handles visible noise on JPEG files very well due to its automatic noise reduction. There isn't a standalone noise reduction setting as this is handled among other Picture Styles options. The cost of the GX8 handling visible noise so well automatically is that sharpness decreases dramatically as you increase the ISO. At ISO 1600 and 3200, I think that the JPEG files look pretty good, but fine details start to be lost and there are some blocky areas around edges and fine details when viewing files at 100%. At ISO 6400, JPEG images become really soft and unnatural in appearance. The already compromised appearance at 6400 just gets much poorer at ISO 12,800 and 25,600.

In low light, the autofocus performance is quite impressive. The GX8 is rated to autofocus down to -4 EV. The GX8 also has a starlight AF feature that turns on when the camera displays 'Low' on the display (or EVF). When activated, the camera is able to detect and focus on stars within approximately the central 1/3 of the frame. The camera also has an AF assist lamp for low-light focusing. Unlike the GX7, the GX8 does not have a built-in flash but it does have a hot shoe and a maximum flash sync of 1/250s.

The GX8 performs well in low light overall. I was impressed by its ability to capture good detail at even ISO 3200 without having excessive visible noise. JPEG files manage to avoid the visible noise that affects RAW files, but the downside is that you also lose a lot more detail than you do in the RAW files. I think that the default noise reduction applied by the GX8 is on the excessive side, personally, as I would prefer to have more noise and also more detail when shooting JPEG files at higher ISO speeds.

A quick camera, with a few caveats

The GX8 has impressive speed performance. Without continuous autofocus, the GX8 can shoot at up to 10fps when using the electronic shutter. When using the mechanical shutter, the maximum speed is a still impressive, but slightly slower at 8fps. When shooting with continuous autofocus, the GX8 can shoot at up to 6fps. The buffer depth is pretty good when shooting RAW and RAW+JPEG image files, at 30 and 32 frames respectively. The JPEG buffer depth is limited by your memory card rather than by the camera, as you can shoot JPEG files until you've run out of space. The buffer is somewhat slow to clear RAW files (JPEGs are very quick to clear), but you can still operate the camera and take images while the files are processing.

Good 4K video, but lack of phase detect autofocus is apparent

The GX8 offers video recording up to 4K at 30fps. In addition, the GX8 can record 1080/60p video, and offers both AVCHD and MP4 video formats. Video performance is quite impressive overall, as the camera makes smooth adjustments to both exposure and focus when recording video. However, the continuous autofocus can be somewhat slow to react to a moving subject, perhaps due in part to the GX8 utilizing contrast detect rather than phase detect autofocus. Autofocus tended to stay locked on quite well when a subject moved only slightly during my testing, but it had a tendency to be slow to catch up to a quickly moving subject.

The sensor-based image stabilization available when shooting still images is not available when recording video, but there is a Hybrid I.S. that combines lens stabilization with lens-based I.S. that works for 1080p or lower resolutions (but not available when recording 4K video). The lack of image stabilization when recording video at 4K is unfortunate, but lens-based I.S. still operates in 4K mode. There are other neat features here too, such as full manual control, on-screen adjustments (allowing you to avoid button and dial noises getting picked up in the audio), focus peaking, and flat picture controls (called Cinelike on the camera). You can even tap on the display to select focus, which works quite well when the camera might otherwise be a bit slow to automatically adjust focus.

There is an external mic jack on the GX8, but it is 2.5mm rather than the more common 3.5mm, so you will potentially need an adapter to plug in a standard mic, but it is a nice inclusion nonetheless. The built-in stereo mic does a good job of recording audio, although it seemed very sensitive by default as it picked up my relatively quiet movement out in the field. Another slight issue I had when recording video is that it is difficult to stop a video recording without jostling the camera because the movie record button is smooth against the top of the camera body and requires a firm press.

4K Photo mode is an interesting feature on the GX8 that allows the capture of 8-megapixel images at up to 30fps -- essentially recording still frames from a 4K/30p video. There are numerous 4K Photo modes, including 4K burst, 4K burst s/s, and 4K pre-burst. When using this feature, a 4K burst file will be saved as an MP4. You cannot record RAW images when using 4K Photo mode, but the image quality is still impressive for what it is. There will of course be a trade-off when recording images at 30fps, but the mode is more than capable of delivering good images when the full-resolution continuous shooting just won't cut it.

Overall, the GX8 has a ton of interesting features for videographers, and it delivers strong performance across its available modes. With full manual controls and on-screen controls, the GX8 has a lot to offer those looking to take control over their video recording. The more automatic video recording options work great as well and provide really solid results for those just looking to easily record great looking video files.

Excellent remote control capabilities

The GX8 makes great use of its Wi-Fi/NFC capabilities through the Panasonic Image App. Connecting the GX8 to the app is easy via Wi-Fi and even easier if using NFC. Once the camera is connected, you are given extensive remote control of the camera. In addition, you can also remotely view and download images from the camera.

For remote functions, you have control of pretty much every important aspect of the GX8. You can change metering, white balance, focus mode, drive mode, file quality, and much more. Unlike many cameras I have tested, you can also change settings on the camera without disconnecting the phone, such as changing exposure mode or focus drive mode. The connection itself is stable and the live feed to my phone was good, especially after increasing the picture quality via the application's settings. Using the display for focus and exposure, which can be set independently on the screen, worked well and the focus point did a good job of keeping up with the touch. You can record video from the app as well. Overall, the GX8 may very well have the best remote control capabilities of any camera I've used. It feels full-featured and could prove to be very useful out in the field in certain situations.

Panasonic GX8 Field Test Summary

The GX8 is an excellent successor to the GX7

What I like:

• Lots of manual controls and a deep front grip
• 20.3-megapixel image sensor captures great images
• Autofocus performance is fast in many lighting conditions
• Impressive high ISO performance
• Very good remote control capabilities

What I dislike:

• Moving the AF area without using the touchscreen is too slow by default
• Lack of built-in flash is disappointing
• The movie record button is difficult to press
• No hybrid image stabilization when recording 4K video

The Panasonic GX8 is a fantastic camera. The camera is a pleasure to use, and its performance is great. The new 20.3-megapixel sensor captures high-quality images, and the camera's metering and autofocus performance ensure that you are able to take full advantage of the sensor. The GX8 also handles well in low light, and its high ISO capabilities impressed me. Ultimately, the GX8 takes what made the GX7 great and makes it even better.