Image quality and samples
The video quality of the GH4 is excellent, especially when filming in 4K and downsampling to 1080p in post. This is another reason to record in UHD rather than cine 4K, as it maintains the same aspect ratio as 1080p.
The “straight” 1080p mode is not bad at all (see the short sample clip on Vimeo), but given there are relatively few disadvantages to recording in 4K, the main reason to record in 1080p would be for higher bitrates for possible broadcast use, or to ease workflows with other 1080p footage. The GH4 can also record 50i/60i footage, as well as AVCHD; we have not yet tested any of these settings.
The image quality from 4K (and 1080p) is detailed, and sharp. The samples here are all with stock settings, but adjusting the sharpening can produce a more pleasing, film-like result. Certainly, it is worth trying out different settings, especially if using the GH4 alongside other cameras.
The test footage here was filmed primarily with two Panasonic lenses: the 20mm f1.7 prime, considered one of Panasonic’s best, and the 35-100mm f2.8. Initially our GH4 came with some dirt on the sensor, which is apparent in the test shots; several rounds of the in-built sensor cleaning mode appear to have solved the issue. We have not corrected the sensor dirt, as not to manipulate the test footage.
As well as a good, detailed image, the GH4 handles low light far better than previous Micro Four Thirds systems. It is not on par with a full frame or even the best APS-C cameras – such as the Nikon D810 or Sony A6000, let alone the Sony A7s. The dynamic range for the GH4 is on par with current pro camcorders, but lags behind cameras such as the Nikon D800 or D810.
The GH4’s native ISO is 800, and the lowest is ISO100; ISO 400 seems to give the cleanest image, perhaps at the expense of some dynamic range. Although the 4:3 sensor is not as sensitive as a full-frame chip, the GH4 will need ND filters for real-world use.
Some reports say it’s best to under-expose on the GH4 slightly, and again this rings true from our tests. Highlights, certainly, are more likely to burn out than on a D800 or 5D, or indeed a camera like the Canon C100. However, anyone who usually uses a conventional pro or news camcorder, in the 1/3 to 2/3 inch chip range, will be happy with the GH4. It just can’t handle quite the wide range of lighting as the 5DmkIII, the D810 or the Sony a7s.
Balancing colours can, though, be an issue with the GH4, and is perhaps one of its principal drawbacks in real-world use.
Nikon DSLRs, although not always the first choice for video, produce an image which cuts together easily with Sony (and other) camcorder clips; the Canon 5D’s footage also seems more edit-friendly.
The GH4 does have quite a distinctive “look”, especially with the native Panasonic glass, but it is not as easy to match colours to other cameras as it could be.
In a multi-camera set up, GH4 footage needs a little more work. Some film makers may also feel its footage is too “video like”, especially set against a camera such as the Canon EOS C300. But Panasonic’s promised Log mode should address this, and in the meantime there are quite a few in-camera controls which can be used to tweak the image.
Another consideration is the GH4’s AF system. Although most film makers prefer manual focus, the GH4’s system, with native lenses, is of the “fly-by-wire” type rather than a full, manual focus control.
Autofocus uses a technique known as “depth to defocus”, which is meant to give smoother transitions between in focus and out of focus shots than conventional, video AF systems. It is fairly accurate, but perhaps not as reliable or versatile as the dual-pixel CMOS AF installed on Canon’s 70D, C100 and now, the 7D mk II. If AF is more of a priority than 4K, then certainly consider Canon instead.
Next: Audio aspects