on trial – Panasonic Lumix DMC-GH4
Panasonic Lumix Dmc-GH4
It’s the little camera currently making a big impact in both the photography and video worlds. Panasonic’s new Lumix G mirrorless flagship represents a true hybrid still/video camera and it’s set some lofty standards for any potential competitor to achieve.
Panasonic applies all its expertise at building pro-level video cameras to its Lumix mirrorless flagship with the result that the GH4 sets new standards for compactness and capabilities. Report by Paul Burrows.
The shallow depth-of-field obtainable with full-35mm size sensors has been one of the reasons video-makers have embraced the D-SLR. Size and affordability – compared to pro-level camcorders – have also been key factors, but now Panasonic is taking things a step further with the GH4. It’s the new flagship of the Lumix G mirrorless interchangeable lens camera system so it’s a still camera in form factor, but it has video recording capabilities that enable it to challenge not only the best HDV D-SLRs, but also the semi-pro video camcorders.
Of course, the GH4 is based on the Micro Four Thirds sensor format which Panasonic also uses in a number of high-end camcorders and others, such as Black Magic, have adopted for dedicated video cameras. MFT is smaller than 35mm – in fact, it’s more like Super 16mm in movie format terms – so there isn’t quite the same inherently shallow depth-of-field, but it’s still a sensor size that’s being quite widely used in a number of areas, including news gathering, documentaries and independent film-making. However, compared to the small format video camcorder, MFT still has greater scope for selective focus while also allowing for a physically smaller camera.
The GH3 hinted at the way Panasonic might be thinking in regard to a hybrid still/video camera, but the GH4 has gone a lot further than anybody expected. In fact, it almost demands reclassification as a video camera that also happens to be a very accomplished still camera. Consequently, it goes beyond anything seen on a mirrorless camera to date and its closest rival in the D-SLR world is probably Canon’s EOS-1D C which, of course, is primarily designed as a video camera.
As we noted with its predecessor, while the GH4 is technically a compact system camera, it’s not really all that compact, especially compared to the likes of the Olympus OM-D E-M1 or Fujifilm’s X-T1, but alongside its main competition in the video world, it’s very small indeed. It’s also much smaller than the EOS-1D C or even the 5D Mark III, likewise Nikon’s D4S and D810.
Like the EOS-1D C, the GH4 can record 4K video, either at the Ultra HD resolution of 3840x2160 pixels at 25 fps or the Cinema 4K resolution of 4096x2160 pixels at the cinematic speed of 24 fps. Both the 4K resolution settings are recorded at a bit rate of 100 Mbps (using the IPB compression regime) which is double the standard mostly set for broadcast quality (and, by the way, represents a massive data-crunching exercise). Furthermore, when the GH4 records at the Full HD resolution, there’s the option of using a bit rate of 200 Mbps (with All-Intra compression) which enhances the picture quality by a significant margin. The GH4 is the world’s first mirrorless interchangeable-lens camera with 4K video recording and, importantly, it also records this resolution simultaneously to its memory card rather than just to an external recorder via the HDMI output.
Given 3D has pretty well flopped (again), 4K is the next big thing in video and the Ultra HD TVs are starting to come thick and fast, but there’s not a lot to show on them beyond what you can record on 4K cameras like the Lumix GH4. The 4K image quality is discernibly better than Full HD – even when downsampled to FHD – so there is justification for upgrading even at this early stage. Given the EOS-1D C arrived back in 2012, 4K has been a slow burn up to now, but the momentum is gathering and it looks like it will become a major part of the video-making landscape, especially as the GH4 it makes it more accessible to both enthusiast-level and professional shooters. In fact, here Panasonic has been very clever because the GH4 can be easily integrated
“The GH4 is the world’s first mirrorless interchangeablelens camera with 4K video recording and, importantly, it also records this resolution simultaneously to its memory card rather than just to an external recorder.”
into a professional video production workflow via the optional DMW-YAGH Interface Unit (also confusingly called the AG-YAGHG, but it looks like the former designation is being used in this market as that’s how it’s described on the Panasonic Australia Website) which has the industry-standard BNC-type connectors for the video output (4K or HD) and balanced XLR-type connectors for the audio inputs, the latter with phantom power for condenser-type microphones. Even though this is quite an expensive component, the combined cost with the GH4 body is still well below what you’d pay for a comparable semi-pro HDV camcorder such as, for example, Canon’s Cinema EOS C100.
Externally, the GH4 doesn’t look hugely different in either styling or size to its predecessor and its magnesium alloy bodyshell is again fully weather sealed. However, both the OLED-type EVF and the external monitor screen step up in resolution; the former to 2.36 megadots and the latter to 1.036 megadots. The monitor screen is adjustable for both swing and tilt, and has capacitive touch controls.
The control layout is centred around a main mode dial (now lockable) on the top deck with front and rear input wheels, a selection of function buttons (for direct access to key items such as ISO, white balance and exposure compensation), and a combined navigator keypad and control ring on the rear panel. As before, there are five multifunction hard keys, but this number is now matched with the ‘Fn’ soft keys that are tabbed in the monitor screen, giving a total of ten user-assignable controls. A total of 54 functions are available for each of the hard keys and 50 for each of the soft keys so the scope for customisation is extensive. There’s also the ‘Quick Menu’ control screen which can be operated using touch control or more conventionally via the navigator and the input wheels. Alternatively, everything is still included in the standard menus so Panasonic has covered all the bases in terms of how the GH4 might be flown – from traditional D-SLR style to touch operations which include autofocusing and shutter release.
The live view screen can be configured in a variety of displays, including a dual-axis electronic level, an exposure meter (with aperture and shutter speed scales), a real-time histogram, guide grids (selected from a choice of three) and a centre marker (particularly useful when shooting video). The histogram can be moved around – by simply dragging it – and positioned as desired while one of the grid displays allows for the grid lines to be moved around by touch as well.
The image review screens number five and can include a highlight warning, a full set of histograms and a detailed info set. The playback functions include thumbnail pages of 12 or 30 images, a calendar thumbnail display, zooming up to 16x and a slide show with a choice of transition effects. The touch controls here include a swipe action for browsing and the pinch action to enlarge or reduce the image size.
On the inside, the GH4 is quite different from the GH3 because just about everything has been either up-graded or tweaked – sensor, processor, shutter, AF system, metering, the WiFi module and more.
The sensor is again a 4:3 ‘LiveMOS’ device with a total pixel count of 17.2 million and an effective count of 16.05 million, but it’s actually a new imager with an extended dynamic range, increased sensitivity range (equivalent to ISO 200 to 25,600) and a faster read-out speed of up to 200 MB/second. It’s supported by a new quad-core processor – called the ‘Venus Engine 9 AHD’ which is really the star of the show given it’s got some heavy-lifting to do, not
just in the video department, but also with the GH4’s up-rated stills capabilities. The maximum continuous shooting speed increases to a rapid-fire 12 fps (with the AF/AE locked to the first frame) and a still handy 7.0 fps with continuous AF adjustment. The burst length with RAW capture increases to 40 frames and 100 frames for maximum quality JPEGs.
The new processor is also behind the GH4’s autofocusing system which still relies solely on contrast-detection measurement, but gets a new control element called ‘Depth From Defocus’ or DFD. This works on data stored in the camera for all the Lumix G lenses, enabling their out-of-focus characteristics – derived from grabbing two frames in quick succession as the lens is focusing – to be used to determine the subject distance and this calculation is then referenced to the contrastdetection AF’s measurement. The lens is then driven pretty well directly to the focusing distance with only minor fine-tuning at the end just as happens with phase-difference detection AF. This increases both the speed and the reliability of the system so it’s particularly beneficial to the continuous AF and focus tracking operations. When a new model of lens becomes available, its out-of-focus characteristics will be automatically uploaded to the GH4 body when it’s first fitted. Additionally, the number of focusing points increases from 23 to 49 – arranged in a 7x7 pattern – which gives a much wider coverage, and the low light sensitivity extends down to -4.0 EV (at ISO 100). A single zone can be adjusted to any desired size to determine selectivity or, alternatively, clusters of nine zones can be selected, but more usefully, there’s a ‘Custom Multi’ mode which allows the number of points and how they’re shaped to be freely adjusted to suit the subject. Manual focusing
“Whichever way you decide to operate the GH4, it’s fast and efficient, but the touch screen controls are particularly well presented.”
is assisted by a magnified image section (which is easily moved around the frame), a simple distance scale and now the much-demanded focus peaking display (selected from two levels and three colours, but yellow and high is particularly effective).
As on the GH3, the GH4 has both a conventional focal plane shutter and a sensor-based shutter which is referred to as an ‘electronic shutter’, although the former is still electronically controlled. Its top shutter speed is lifted to 1/8000 second and the maximum flash sync speed to 1/250 second. Additionally, Panasonic now rates the shutter assembly at 200,000 cycles. The sensor shutter offers the advantages of completely silent operation and no lag so it enables a continuous shooting speed of 40 fps with JPEG capture.
The GH4’s built-in flash is supplemented by both a hotshoe and PC terminal, but as on the GH3, it’s a pretty capable unit in its own right. In addition to the standard modes of auto, fill-in, red-eye reduction, slow speed sync and second curtain sync, it also allows for manual control (down to 1/128 power) and can served as the commander for a wireless TTL flash set-up. Flash compensation is available over a range of up to +/-3.0 EV, and the angle of coverage matches the 12mm focal length in the Micro Four Thirds format (effectively 24mm). Incidentally, all exposure settings can be adjusted in either one-third or full stop increments.
Light And Shade
The GH4 gets Panasonic’s latest 1728-zone multi-pattern metering system and the alternative measuring methods are centre-weighted average and spot.
The standard set of ‘PASM’ exposure modes are supplemented by program shift, an AE lock, up to +/-5.0 EV of compensation (applied in 1/3 EV increments) and auto bracketing. But the GH4 goes without any manually selectable subject/scene programs – which makes sense on a camera of this calibre – although the ‘iAuto’ modes have automatic scene selection which chooses from ten possible scenarios. The other ‘iAuto’ components include backlight compensation, dynamic range expansion processing, sensitivity adjustment, focus tracking,
face detection and recognition, red-eye removal and ‘Shading Compensation’ which corrects for lens vignetting. There’s also an ‘i.Auto+’ mode which provides limited manual adjustments for depthof-field, brightness level (i.e. exposure compensation) and colour balance. These are done via touch control using on-screen sliders.
The key ‘i.Auto’ processing functions are also available for use with the ‘PASM’ modes, including dynamic range expansion processing – called ‘Intelligent Dynamic’ – long exposure noise reduction and ‘Intelligent Resolution’ processing. ‘Intelligent Resolution’ can be set to Low, Standard or High, and it detects outlines, textures and areas of soft gradations, subsequently enhances the edges to increase the definition and the appearance of sharpness. Interestingly, the GH4 inherits the Highlight/Shadow adjustment control from the Olympus OM-D cameras, but with some added capabilities such as being able to save three adjustments as well as access a number of presets. It works in the same way as on the Olympus cameras – i.e. like a simplified version of Photoshop’s Curves – with adjustments applied to a tone curve displayed in the monitor screen. The front wheel tweaks the highlights while the rear dial works on the shadow. Still on managing exposure and contrast, there’s a multi-shot HDR capture mode with the choice of an Auto setting or three manual settings for exposure adjustments of +/-1.0 EV, +/-2.0 EV and +/-3.0 EV. There’s also an auto align function. The choice of ‘Creative Control’ special effects increases to a dizzying 22, but the choice of ‘Photo Style’ picture presets remains at six. The five colour presets have adjustable parameters for contrast, sharpness, colour saturation, hue and noise reduction. The Monochrome preset has a colour tone adjustment (from sepia to cyanotype) and a set of contrast filters (i.e. yellow, orange, red and green). One customised ‘Photo Style’ can be created. The white balance control options are the same as those provided on the GH3 and comprise auto correction supplemented by five presets and four custom measurements (increased from two) plus manual colour temperature setting from 2500 to 10,000 degrees Kelvin. Fine-tuning is available along either the blue-to-amber or green-to-magenta ranges with auto bracketing in one or the other performed over a sequence of three frames.
As noted at the start of this review, the GH4 can record in the ultra-high 4K resolution – either Ultra HD at 3840x2160 pixels and either 25 fps (PAL TV standard) or 24 fps; or Cinema 4K at 4096x2160 pixels and 24 fps (which actually is a true 24 fps). With IPB compression, the bit rate is an impressive 100 Mbps, delivering a huge amount of picture quality. Here there’s the choice of using the MOV or MP4 formats, but this is really just the start. For Full HD capture there’s also the AVCHD Progressive and AVCHD formats on the table, plus the choice of the IPB or All-Intra compression regimes. So, for example, you can record at the Full HD resolution in either MOV or MP4 (at 50, 25 or 24 fps) with All-Intra compression, giving a massive bit rate of 200 Mbps; or choose between 50 and 100 Mbps using IPB compression. ALL-I compression is performed frame-by frame (rather than in multiple frames as happened with IPB) so it allows for much easier editing, but the file sizes are comparatively large. The bit rates with AVCHD are obviously lower, but the best is still 28 Mbps (at 1080/50p). Incidentally, unlike the GH3 which was region-specific in terms of television standards, the GH4 allows for the selection of either NTSC or PAL frame rates (plus the 24 Hz cinema mode) which is done in the Set Up menu. For those delving deeper into video performance, the GH4 delivers a ‘clean’ uncompressed feed (4:2:2 colour space at 8-bit or 10-bit) to its HDMI connection for recording to an external device. Of course, firstly you’ll need to find a recorder that handles 4K video at 10-bit 4:2:2. More importantly, the data is also simultaneously recorded to the memory card to provide a backup (albeit at 4:2:0 and 8-bit). Perhaps the biggest surprise here is that the GH4 only has one memory card slot rather than two, but it does support the new ‘Speed Class 3’ (U3) SDHC and SDXC cards which are optimised for 4K video, having a minimum write speed of 30 MB/per second.
While the GH3 had a few pro-level video camera features such as time code support and a choice of frame rates for creating fast or slow motion HD footage, the GH4 gets pretty much the full suite. There isn’t space here for full explanations of each, but the important ones are a zebra pattern generator (indicates overexposed areas), master pedestal (sets the black level as a reference for subsequent brightness adjustments), ‘CineLike Gamma’ (two settings – Cine D and Cine V – giving different tonalities, a bit like colour presets), colour bars and a 1.0 kHz test tone (for benchmarking the colour and sound respectively), and luminance level (sets tonal range, based on histogram brightness levels – i.e. 0-255).
The GH4 offers a big choice of variable frame rates (VFR), ranging from just 2.0 fps up to 96 fps which, when recording at 24 fps, gives a quarter speed slow-mo. The selection of settings varies according to the recording format. Time-lapse and stop motion animation modes are also available.
On the audio side, the GH4 has built-in stereo microphones with adjustable levels (-12 dB to +6 dB), a level limiter (or attenuator) and a wind-cut filter. It has both a stereo audio input and an output – both standard 3.5 mm minijack terminals – while in either the MOV or MP4 video modes, soundtracks can be recorded in the higher resolution LPCM (Linear Pulse Code Modulation) format.
The features available when shooting video include the full set of ‘PASM’ exposure control modes, continuous autofocusing with tracking and face detection, the ‘Photo Style’ presets and the key ‘i.Auto’ corrections of i.Dynamic and i.Resolution plus the Highlight/Shadow adjuster.
A potentially significant aspect of 4K video is that it’s possible to extract still images sized at a useful 8.3 megapixels. A firmware update for the GH4 adds the new ‘4K Photo’ mode Panasonic has introduced on two subsequent Lumix models. Pressing the ‘Fn1’ button during recording tags a frame which can subsequently be extracted as a JPEG image with a resolution of 3840x2160 pixels. This upgrade also adds 4K video recording at 24 fps in the MP4 format. By the time this article is published, the upgrade will be available at http://panasonic.jp/ support/global/cs/dsc.
Speed And Performance
Panasonic supplied one of its new Gold-series Speed Class 3 SDHC cards so we could record 4K video with the GH4, but for our speed tests for still capture we reverted to our reference 64 GB Lexar Professional SDXC card which is a UHS-I device (but Speed Class 1 just to confuse things). With continuous AF/AE operating, the GH4 fired off 75 JPEG/large/ fine frames in 10.71 seconds which represents a shooting speed of 7.0 fps. We just chose 75 frames as an arbitrary number, the camera would happily have motored on at full speed to the buffer’s maximum of 100 frames. With the AF fixed to the first frame, a burst of 80 frames was rattled off – and that’s what it sounds – like in 6.625 seconds so the shooting speed was 12.07 fps. While these numbers are impressive in themselves, just when you’d need bursts of 75 or 80 frames is debatable, but then not much is going to get away from 12 fps! While much of the hoopla surrounding the GH4 has been about its remarkable capabilities as a video camera – and
they are undoubtedly remarkable – it’s a very fine still camera too. Both Olympus and Panasonic have conclusively proved the naysayers wrong with the image quality that they’re now extracting from Micro Four Thirds size sensors. Certainly with the Lumix GX7 and both the OM-D E-M1 and E-M10 models we’ve seen performances that at least match that of comparable ‘APS-C’ CSCs or even do better in some areas… including, interestingly, sharpness. The GH4’s maximum quality JPEGs are a joy to behold – beautifully detailed, richly coloured and with a surprisingly wide dynamic range (without resorting to any form of expansion processing). Good detailing is held in both the deeper shadows and the brighter
“On the inside, the GH4 is quite different from the GH3 because just about everything has been either upgraded or tweaked – sensor, processor, shutter, AF system, metering, the WiFi module and more.”
highlights. Colour reproduction is accurate across the spectrum and the camera handles both subtle shades and fully saturated tones with equal aplomb. Noise just isn’t an issue up to ISO 1600 – very good for an MFT camera – and only starts to become noticeable at ISO 3200 as the reduction processing starts to diminish definition. You can still shoot at ISO 3200, but the higher sensitivities become restrictive in terms of how large these images can be reproduced. The ISO 25,600 setting is probably a last resort, assuming there is just no other way of getting more light into the camera.
The new AF system is so fast the image simply snaps into focus in the EVF or on the monitor screen and we didn’t encounter any situation where it wasn’t absolutely reliable. Whichever way you decide to operate the GH4, it’s fast and efficient, but the touch screen controls are particularly well presented. However, having the WB, ISO and exposure compensation buttons situated close to the shutter release makes them easy to access in a hurry. The WiFi functionality is enhanced by the provision of NFC which makes for a fast hook-up with mobile devices and the remote control capabilities facilitated through the Image App could be particularly useful when the camera is in a video rig. Right now evaluating 4K video isn’t exactly straightforward – although this will change as more displays become available – so we shot some Ultra HD footage and then had a look at it in Final Cut Pro X which subsequently downsamples it to Full HD. Shooting in 4K provides scope for both cropping or enlargement without sacrificing quality, and the downsampled 1080p footage exhibits clarity, colour and contrast that are nothing short of stunning and, worse, addictive. Prepare to upgrade! The still frames pulled from 4K footage are also remarkable – well, they’re around 8.0 megapixels – and you’d have to think there are going to be implications here in the future.
In a nutshell, the Lumix GH4 is a masterpiece and it will undoubtedly have rivals banging on the doors of their product planning departments, demanding action. On the video side, it’s nothing short of brilliant even if you take the 4K recording out of the equation (but it’s ready and willing). The combination of capabilities, compact size and sheer affordability is unmatched anywhere else in the video world. Even throwing the comparatively bulky Interface Unit into the mix – which turns the GH4 into a fully-fledged pro video camera – doesn’t alter the equation in terms of capabilities-versus-mobility.
As a still camera, the GH4 is equally accomplished, although perhaps not as precociously talented here as its video alter-ego. Nevertheless, the combination of capabilities, usability and performance is a highly desirable one. And even if you’re resisting video’s siren song right now, if 4K really takes off you won’t be able to anymore, and then you’ll be thankful for Panasonic’s foresight. Ironically though, while the GH4 may be the most advanced hybrid mirrorless camera on the market, it also has one of the most traditional of control layouts so it still handles and works like a D-SLR.
So, just about any way you look at it, the GH4 is the answer.
On the inside the GH4 has a new sensor and processor, a faster shutter, and upgrades to its AF and metering systems.
Main mode dial provides direct access to the GH4’s ‘Creative Control’ special effects which now number 22.
Bodyshell is magnesium alloy and fully sealed against the intrusion of dust and moisture. Styling and size little changed from those of the GH3.
Old-style dial sets drive modes, auto bracketing and self- timer. With the AF/AE locked to the first frame, the GH4 can achieve a shooting speed of 12 fps.
The GH4 is compatible with the new breed of super-fast ‘Speed Class 3’ SDHC and SDXC memory cards to enable the recording of 4K video. There’s still only one slot though.
Built-in stereo microphones are adjustable for recording level and have a wind-cut filter.
The OLED-type electronic viewfinder upgrades to a higher resolution of 2.359 megadots and is one of the best EVFs around right now. Buttons for direct access to white balance, ISO and exposure compensation very handily placed
just astern of the handgrip.
Live view screens showing (from left) a dualaxis level display, real-time histogram (which can be moved around) and an exposure meter.
Test images captured as JPEG/large/ fine frames with the Lumix G X Vario 12-35mm f2.8 ASPH zoom lens. Definition, colour, tonal gradation and dynamic range are all excellent and noise isn’t an issue until ISO 3200.
‘Quick Menu’ control screen in live view allows direct access to a wide selection of capture functions.
The monitor control screen can be used with touch control or navigated conventionally.
Replay screens showing basic capture info (left) and a set of LRGB histograms (right).
The GH4 menus are logically arranged and easy to navigate.