Panasonic DMC-GH2 Review
Video and the GH2 (cont.)
Video Image Quality
One of the issues with all HDSLRs, including the GH2 is aliasing and moiré. The reason for this is that although these cameras all have AA filters on their sensors, they are optimized for high-resolution still images, not ~2MP 1080p video capture. Being a dedicated video camera, the Panasonic AF100 features an AA filter for 1080p but as a result it cannot produce high-resolution stills.The GH2 actually controls moiré very well, much better than some of its competitors. Where moiré is visible at all, it is monochromatic rather than colored, which is far less intrusive.
|Normally, in a scene like this we'd expect to see moiré in the roof tiles, accentuated by the panning of the camera. However, this video shows virtually no moiré, which is impressive from a camera designed first and foremost to capture stills. Usually we would expect to see more moiré from footage captured at 720p compared to 1080 but as you can see, footage from the GH2 in either resolution is impressively clean.|
Anyone familiar with video in DSLRs knows about rolling shutter. Also known as 'jello cam', rolling shutter (where vertical lines appear slanted when the video is panned) is a consequence of how CMOS sensors are designed. Data from the sensor is read out in lines from top to bottom, which means the bottom lines are read later than the top. This is fine for still images, but in video it can result in 'jello cam'. We're pleased to report that although the rolling shutter effect is noticeable when the camera is very rapidly panned from side to side, it is well-controlled and in no way problematic in normal use.The GH2 offers automatic focus during video recording but during our shooting we found that it is hard to get predictable results. Experienced videographers are more likely to focus manually, and fortunately, the GH2 supports a very powerful magnification mode that makes manual focus very easy. If you set the GH2 to MF and use Micro Four Thirds or Four Thirds lenses, simply rotating the focus ring on the lens activates a magnified view. With other lenses the magnified view is activated by pressing the adjustment dial inwards. The Panasonic AF100 also features focus aids but they are not as powerful, or as useful as the GH2's magnified view - one area where the GH2 clearly scores points, especially when using older, third-party manual focus lenses via adapters.
Most of Panasonic's Micro Four Third lenses feature Mega O.I.S image stabilization. Whilst we have found this system to be highly effective for still photos, it isn't quite so useful for video footage. It's fine for grab shots and casual shooting, but for critical video work we really would recommend a tripod, or at least some sort of external support. When mounted on a tripod, O.I.S. is best set to "off".
Mega O.I.S 'On'
1920 x 1080, 60i, 20.6MB. Click here to download original .MTS file
|With Mega O.I.S turned 'on', footage is far from completely stable, but compare this clip with the one below - Mega O.I.S has done an extremely good job of reducing the worst of the camera shake. This clip still displays a slightly queasy up/down, left/right 'snaking' but this is partly due to the system's response to the camera being panned. It is interesting to note that this amount of biaxial movement is just enough to show the rolling shutter effect, too.|
Mega O.I.S 'Off'
1920 x 1080, 60i, 12.26MB. Click here to download original .MTS file
|This video was shot handheld using the Panasonic 100-300mm f/4-5.6 at 200mm with Mega O.I.S turned off. If you compare this clip to the one above, you can see how much work the system has to do to stabilise the GH2's video at this focal length. Camera shake is so intense that it renders this clip completely unuseable.|
Moving on to audio, and as far as we're concerned, the GH2's internal stereo microphone is about as good as things get in this type of camera. Professional filmmakers don't tend to bother with internal microphones, but naturally they can come in handy on occasion and the GH2's built-in audio is perfectly acceptable for everyday video shooting and 'grab shots'.
Adding an external microphone to the GH2 is easy via the 2.5mm audio jack. There are plenty of microphones available to fit a 2.5mm jack (and needless to say, Panasonic makes one, the DMW-MS1) but if you already own recording equipment that uses the more standard 3.5mm, you'll need to invest in an adapter.
Something that can be a problem with internal microphones is wind noise in footage shot outdoors. The GH2's inbuilt microphone is very good, but wind noise can be an issue in some situations. Fortunately, the GH2 has an effective wind noise reduction feature for its inbuilt mic.
Wind Cut 'Off'
|1920 x 1080, 60i, 15.06MB. Click here to download original .MTS file|
|The GH2's inbuilt microphone is very good, but wind noise can be an issue, as you can hear in this video clip, shot on a windy (and rainy) day with wind cut turned 'off'.|
Wind Cut 'Standard'
1920 x 1080, 60i, 14.02MB. Click here to download original .MTS file
|With wind cut set to 'standard', the impact of wind noise on the GH2's footage is reduced, as you can hear from this clip.|
Wind Cut 'High'
1920 x 1080, 60i, 15.06MB. Click here to download original .MTS file
|Set to 'high', the GH2's wind cut function is very effective at reducing moderate wind 'boom', whilst letting (most of) the ambient noise through onto the audio soundtrack. It can't work miracles though, and in windy conditions, an external microphone with a physical wind cut filter is far preferable.|
Still on the topic of audio, modern professional audio equipment uses XLR cables and connectors. This is where higher-end video cameras like Panasonic's AF100 shine. Incorporating these big XLR inputs in a small camera like the GH2 just wouldn't be possible. If you want to create perfect sound with the GH2 you'd be well advised to invest at least in an accessory microphone, but ideally an external sound recorder.
Shooting Video with the GH2: ConclusionIn our opinion, the Panasonic Lumic DMC-GH2 defines the current the state-of-the-art for video in DSLRs and interchangeable lens cameras. The large, high-resolution EVF is a big plus compared to some other HDSLRs, and we love the manual focus assist magnification feature. For nature and wildlife filmmakers the ETC (Extra Tele Conversion) function allows long telephoto movies not possible before at this quality, price, size and weight. More fundamentally, at its core the GH2 also features an improved video codec compared to the GH1.
Comparing the GH2 to consumer camcorders at a similar price point is problematic, since the Four Thirds sensor is so large - a fact that has huge implications for image quality and depth of field control. On the other hand, the fact that the GH2 (like all interchangeable lens still cameras) does not feature a motorized zoom or built-in ND filters is relevant, and both omissions might limit its usefulness to serious videographers.
Ultimately, as well as built-in ND filters, we would like the GH3 to feature a swivel EVF with larger magnification, and some better tools (such as a waveform monitor) for controlling exposure. Also, although the GH2's video codec improves on the GH1, there is still room for improvement: 10 bit color depth, higher bit rates and 4:2:2 color compression would be nice, as well as improved continuous AF. Overall though, the GH2 is a big improvement over the GH1, and a major step into the right direction. Putting specification to one side for a moment, it is also a pleasure to use, both as a video and stills camera.
Uwe Steinmuller is a photographer, filmmaker and writer based in California, and is the co-author of Mastering Video with Your DSLR. You can see more of his work at www.outbackphoto.com
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