Panasonic Lumix GX850 Review

Performance starts with image quality, which is the criteria used as the foundation of our digital camera ratings. Ergonomic issues may get in the way, but in the end, image quality counts the most. For an ILC, image quality greatly depends on the lens used. While color, noise, exposure and dynamic-range are properties of a camera, distortion, vignetting and chromatic aberrations are properties of the lens. Sharpness and contrast depend on the weakest link. That is, a camera cannot capture more details than a lens lets through. Conversely, it is possible for a lens to transmit more details than a sensor can capture.

Image Noise & Details

The Panasonic Lumix GX850 shows good image quality with low image-noise up to ISO 1600. Noise-reduction can be adjusted in 11 steps, more than most cameras. This ranges from virtually no removal to brutally destroying image details. The default setting is overly aggressive and cause a noticeable degradation of details. At -2, noise-reduction does a nice job of balancing details and image-noise which is almost entirely achromatic.

Noise is minimally visible at ISO 3200 with just a hint of softness. Images remain very usable with good dynamic-range and contrast. The same cannot be said of ISO 6400. There, image contrast takes a dip and the camera loses a substantial amount of dynamic range. Still, colors are well maintained and noise-reduction maintains a very good balance between image noise and details. From ISO 3200, maximum print sizes get affected. Still, mid-size prints can look quite reasonable.

ISO 12800 becomes a little worse yet less than expected. Given how different the jump from ISO 3200 to 6400 is than the one from ISO 6400 to 12800, that must be the point at which the camera switches into Expanded ISO mode, although the GX850 only labels ISO 100 as expanded. There is a little more noise and less detail at ISO 12800, limiting prints to relatively small sizes.

The maximum sensitivity of ISO 25600 is very noisy and details are severely impacted. Only the smallest prints are possible at this point but this can be acceptable for web-use. Dynamic-range is also reduced here. One thing that is impressive is that the camera manages to maintain its color-accuracy throughout the entire sensitivity-range.

While image-noise is much better controlled on the GX850 than on the GM1, this appears to come at the expense of sharpness. Even at base ISO, this mirrorless is never critically sharp. The default sharpness level seems to attempt to compensate for this but shows some artifacts along hard-edges. A Sharpness setting of -1 proves to be better but there is not much room between too-soft and over-sharpened. Shooting RAW can yelp better results, depending on the conversion software.

Color & White Balance

Color accuracy is good but never perfect. Saturation is exaggerated by most styles, except Natural, at the default settings. Since Natural is slightly dull by default yet with good hue, starting with this style and setting Saturation to +1 gives the most realistic output. Contrast is nice at 0, which is the default.

Automatic While-Balance performance is better than average. It compensates well for a good variety of lighting, producing results with a minimal cast under most conditions. To perfectly control color-balance, Custom White-Balance is spot on. One very welcome feature of the GX850 is that the LCD can be adjusted in terms of Saturation and Tint along 2 axis. This makes it possible to calibrate the display so that it correctly previews white-balance. What this effectively does is allow white-balance fine-tuning to to be set reliably.

Exposure & Dynamic-Range

The Panasonic GX850 has a fairly good multi-segment metering system which favors brighter exposures. Overexposure happens regularly in the presence of small highlights but also with moderately-sized ones in scenes of high contrast. Under-exposure is not much of an issue but does happen. Overall, this camera produces optimal exposures more often than not. When it misses, it rarely does by more than 1 EV.

Given that this camera offers two shutters, its behavior at extremes of brightness can be surprising. When using the ultra-quiet Electronic-Shutter, it can capture extremely bright scenes with shutter-speeds up to 1/16,000s. The Mechanical-Shutter, however, only attains a maximum of 1/500s. In low-light scenes, the situation is reversed with the minimum shutter-speed of 60s only possible mechanically. Otherwise, exposures are limited to 1s.

It is important to remember that the LCD is rarely Exposure-Priority so it only previews exposure for scenes which fall well within the metering range while the camera is in an automatic or semi-automatic mode. The optional live-histogram is not entirely reliable either since it represents the display and not the exposure. In Manual mode, the display can optionally be Exposure-Priority.

Dynamic-range on this mirrorless is typical of cameras with Four-Thirds sensors. It manages to capture around 12 stops at ISO 200 which is the native sensitivity of the GX850. From ISO 100 to 800, there is little loss of dynamic-range which can nicely capture typical outdoor scenery. In low light when sensitivities of ISO 1600 or higher are needed, dynamic-range loses a fair amount. This makes clipping of highlights more common which, in turn, requires more negative EC than usual.

Auto Focus

This mirrorless digital camera has a quick Contrast-Detect autofocus system. It usually locks focus quickly and accurately. Even under relatively low-light it nearly always takes under ½s to lock focus. Once again, this is a performance that compares with recent mirrorless cameras, which are faster then when we reviewed the GM1.

To speed things up, Panasonic provides an option called Quick-AF. In this mode, the Panasonic Lumix GX850 starts focusing as soon as the camera is held steadily, presumably because the photographer is preparing to take a shot. When the shutter-release is pressed halfway, the GX850 then only needs to adjust focus a little.

Speed

The Panasonic GX850 is very responsive. Every button press and dial turn is immediately registered. This is just as good as any modern mirrorless camera. Its performance is characterized by the following numbers:

• Power-On: About 1½ second, assuming the lens is not collapsed. Average.
• Power-On to First-Shot: 2 seconds. Average.
• Autofocus: ¼-½s, even in low-light. Very good.
• Shutter-lag: Instant with under ¼s blackout. Excellent.
• Shot-to-shot: ¾s with AF, ½s without. Still average.
• Playback: Instant to enter, ½s to exit. Good.
• Power-Off: Just over 1½ seconds. Below average.
• Video: Just under ½s to start, 1s stopping delay. Below expectations.

For an entry-level digital camera, the Panasonic Lumix GX850 is performs in-line with recent mirrorless models on most metric. The Contrast-Detect AF system though stands out by being quite fast. On the other hand, there are an unwanted delays to start and stop video recording. This must be due to the lack of a dedicated video mode which also causes a jump in framing as recording starts.

The one last performance number is battery-life. At 210 shots-per-charge, this is well below average but is certainly excusable considering the compact size of this camera and its battery. The real problem is that simply buying additional batteries does not quite solve the problem. Charging being internal, each time a battery needs to be charged, the camera must be attached via a MicroUSB cable to another device.

The Panasonic Lumix GX850 improves upon the GM1 on nearly all aspects while maintaining an exceptionally compact size. With image mirrorless image-quality and speed from such a small body, it provides a worthy alternative to Premium Compact cameras, at least with a small lens. Combined with the Lumix G 12-32mm F/3.5-5.6 ASPH Mega OIS, it becomes exactly that: A small camera with exceptional image-quality.

While it offers a minimal number of external controls and just a single control-dial, the GX850 is quite feature rich. Several of its exceptional features revolve around the sensor's 4K output. 4K Ultra-HD video is obviously one of those. So are Panasonic's own 4K Photo Burst and Post Focus modes which enables the camera to perform Focus Stacking. Unusually for an entry-level camera, the GX850 offers Interval Timer, Time Lapse, Spot Motion, HDR and Multiple-Exposure features, plus bracketing for exposure or white-balance.

Output quality from the GX850 shows impressively low image noise, nice colors and better than usual white-balance. Metering is fairly good, only with a slightly higher tendency to over-expose highlights than before. It lags a little in terms of dynamic-range and absolute sharpness, but there is little to complain about when it comes to image quality.

The GX850 is a very responsive mirrorless. It is fast where it counts, like autofocus and shutter-lag. Video is where it literally lags and the lack of a dedicated mode for it should be a deal-breaker for any videographer. The worse performance of this camera comes from its short battery-life which is unfortunately problematic due to internal charging.

The crucial issue with the GX850 is truly what it lacks, a viewfinder. There is no built-in EVF nor support for an optional one. This means that framing must be done with the LCD which is a fairly good one but can can washed out under bright light. At one point, Panasonic produced a GM5
Panasonic Lumix DMC-GM5 to succeed the GM1. That mirrorless had a built-in EVF, similarly to a good number of current premium cameras. When it comes to competing with those premium cameras without a viewfinder, the GX850 is certainly competitive though.

There are two cases where the Panasonic Lumix GX850 is most compelling. First, as a highly-capable premium compact, albeit one without a viewfinder, where the GX850 easily wins in terms of image-quality and autofocus speed. The second case is as a backup to another Micro Four-Thirds camera. It is capable of working with the entire lineup of Micro Four-Thirds lenses from any brand yet takes very little space. This is pretty-much the smallest a backup camera can get.