Lumix GH4 Review

The big news from Panasonic this year is the Lumix GH4. There is a tradition that the version number four is dropped when incrementing a camera model name. For example, there was never a Lumix G4 or GF4. The reason for this is that the word for "four" rhymes with the word for "death" or "disease" in some Asian languages.

However, there are two reasons why Panasonic still used the model name "GH4": One is that professional cameras often still carry the number four. We have the professional Nikon D4, for example. The manufacturer probably reasons that the users of a professional camera is less likely to be superstitious.

The other reason is that the main new feature of the GH4 is 4K video. So it makes good sense to use the model name GH4.

From the outside, the GH4 looks very much like the predecessor GH3:

The body is molded slightly differently over the flash, but other than that, the shape of the camera bodies is pretty much identical. The button layout is also the same. However, there are some small, but important differences.



Not visible in this picture, the inside of the grip is molded slightly differently. When holding the grip, you can notice that there is an additional ridge which gives a more confident grip for your fingers.

On the left shoulder, there is the drive mode wheel:

Lumix GH3 (left) and Lumix GH4 (right)

The drive mode wheel gains another setting for time lapse mode. But more important, for me anyway, is that it has become more stiff. With the GH3, the drive mode wheel would often be dislocated as I took the camera out of the bag, but that just doesn't happen anymore with the GH4. This little details is important for me.

On the right hand shoulder, we again have the same layout. This time, the mode dial has lost one setting, the scene modes. I guess most people would agree that scene modes don't belong on a professional camera anyway, so I don't see this as any loss.

Lumix GH3 (left) and Lumix GH4 (right)

Also, the mode dial of the GH4 gains a locking function. Press the top button once, and the model dial is locked. Press it one more time, and it is unlocked. The mechanism is the same as the one found on retractable ballpoint pens.

The SD card door looks the same, but again, it has been improved. On the GH3, the door would easily open by a mistake when taking the camera out of the bag, but the GH4 implements more friction in the locking mechanism, so that this doesn't happen. Good stuff!

Also, while the red movie button looks just the same, the new one has a better feel to it. You feel like you have more control over it. With the GH3, I had to just press the button hard and hope the camera reacted. With the GH4, the button gives me better feedback.

The GH4 gains a new drive mode for time lapses	and loses the mode setting for scenes
The ISO button gets one more dot, making it easier to feel	The front Lumix logo loses the cheesey gold colour

Even if the top side of the flash is molded differently, the flash itself has the same pop up mechanism, and provides the same coverage as before.

EVF

The GH4 gets a bigger rubber eyecup around the EVF. This is a good thing. After all, one typical use for the EVF is in strong sun light. And a bigger eye cup better protects against the sun, making it more probably that you can actually use the EVF. This is especially good news for people who wear glasses.

Lumix GH3 (left) and Lumix GH4 (right)

Even if the viewfinder optics appear the same from the outside, I find the GH4 EVF to be a solid improvement over the GH3. Even when wearing glasses, I can see more of the image at once, and much more clearly. It has a 35% higher resolution, as well.

In use

The Lumix GH2 had a big flaw: The buffer clearing speed was horrible. If you took a series of pictures in RAW, the camera would clog up for an annoying period while writing to the SD card, even if you had a very fast SD card. The GH3 fixed this, and the GH4 is even faster.

Speaking of SD cards, I've found that a Sandisk Extreme 45MB/s SD card is good enough for all video modes. However, if you plan on using the 200Mbps All-Intra mode a lot, you could invest in the even faster Sandisk Extreme Pro 95MB/s card.

The most recent and very expensive Sandisk Extreme Pro UHS II cards are not needed, in my experience. Read mode about my test here.

Photography

The Lumix GH4 has a new sensor, compared with the GH3. However, the image quality improvements are not massive. You should notice somewhat cleaner images at high ISO, and there is a slight improvement of the dynamic range.

One significant improvement is the mechanical shutter unit. It is faster, and slightly less audible. This gives you a higher frames per second rate, and it also ups the flash sync speed from 1/160s to 1/250s. The maximum shutter speed also increases from 1/4000s to 1/8000s.

Another improvement is the electronic shutter mode. The GH3 had a very slow electronic shutter readout speed of 1/10s. This gave very severe rolling shutter artefacts, see some examples here.

With the GH4, this readout speed increases to 1/30s. This is still not fast enough to be safe against all rolling shutter artefacts, but this should be less of an issue.

The downside of the new electronic shutter implementation is that it drops two (out of 12) bits when reading of the sensor values. This gives you less dynamic range when using the electronic shutter. It is not much of an issue, you would typically only notice more noise if you lift the shadows a lot in post processing. Read more about this here. So to get the best possible image quality, use the mechanical shutter, not the electronic shutter. For most real life situations, though, the difference is very small.

Video

The Lumix GH4 gets faster video processing, allowing for faster autofocus during video recording.

There is a comparion of the video speed with some prime lenses here, and with the two f/2.8 zoom lenses here. The GH4 generally performs better, as you would expect.

One thing to notice, is that the autofocus performance while recording 4K video is very poor. So if you need to rely on continuous autofocus during video recording, go for the 1080p mode. That will give much more dependable autofocus, and a higher framerate to boot.

But 4K video is the big news. The Lumix GH4 is the first mirrorless camera to support 4K video.

Resolution	Framerates
4096x2160 (17:9, 1.85, Cinema 4K)	24p
3840x2160 (16:9)	25p, 30p
1920x1080 (16:9)	24p, 25p, 30p, 50p, 60p
1280x720 (16:9)	24p, 25p, 30p
640x480 (4:3)	25p, 30p

There is a drawback with 4K video, though, the camera only uses parts of the sensor at this resolution, as illustrated below:

As the Lumix GH4 does not have the multi aspect ratio sensor, just like the Lumix GH3, there is a crop factor when switching from photos (4:3) to 1080p video (16:9). The sensor diagonal is 8% shorter in 16:9 than 4:3, meaning that there is an additional crop factor of 1+8% = 1.08. So in 1080p video, a 14mm lens behaves like a 15mm lens in terms of the diagonal field of view. This is just like the Lumix GH3.

With the Lumix GH4 in 4K video mode, though, the crop factor is much larger. In 4K mode, multiply the focal length with 1.31, and in Cinema 4K mode, use 1.24. So the 14mm lens becomes equivalent to 18mm and 17mm, respectively. See the table below:

Resolution	Sensor area used	Diagonal	Crop factor
Photos (4:3)	4608x3456	5760	1
1920x1080 (16:9, Full HD)	4608x2592	5287	1.08
4096x2160 (17:9, 1.85, Cinema 4K)	4096x2160	4631	1.24
3840x2160 (16:9, 4K)	3860x2160	4406	1.31
1920x1080 (16:9, Full HD, ETC mode)	1920x1080	2203	2.6

So all your lenses become "more narrow" when using the 4K feature. The reason for using only a part of the sensor area for 4K video is processing power: If the camera would use the whole sensor area and then scale it down to around 4000 pixels horizontally for each frame, this would require far too much processing. A high quality rescale, to avoid artefacts, requires a lot of CPU resources.

Another welcome news, is that the Lumix GH4 is the first Panasonic Micro Four Thirds camera to be multi region, in the sense that it can record both 25p and 50p (PAL region) and 30p and 60p (NTSC region) using the same unit. The camera requires a reboot when switching region.

This means that you can choose between using 50p or 60p (for full HD video capture), and between 25p and 30p for 4K video capture. Previously, you were only able to use one of them, depending on where you bought the camera in the first place.

Normally, you would want to use the "correct" setting for your own location. For example, if you are in a PAL region, and use 30p, you could risk getting an interference between the video framerate and the frequency of artificial light, causing an annoying flickering. Here is a demonstration of how this might look like. However, having the choice between 25p and 30p is very good.

The Lumix GH4 is the first Panasonic M4/3 camera to handle 50/60 FPS combined with the video ETC mode. The GH3 could only do ETC in 24/25/30 FPS.

There are other improvements as well. For example, the GH4 features a zebra pattern to warn against overexposure during video recording, and also implements focus peaking. See focus peaking demonstrated with the Sony NEX-3N.

The competition

Here's the thing: Not many cameras feature 4K video yet. If you want an interchangeable lens camera with 4K video, the only other choice is the Canon EOS 1D C, which is a rather large DSLR camera. There are also the professional RED digital video cameras, but they are out of the scope for the consumer market.

Blackmagic say they have a 4K video camera in the works, however, it has been delayed a lot. In the mean time, they have the Cinema Camera capable of 2.5K video at a high dynamic range.

About a year ago Nikon said that they would implement 4K video in their Nikon 1 range of mirrorless cameras. However, nothing of the sort has surfaced, and the Nikon 1 range does not appear to be doing well in the market.

Looking at the non-interchangeable lens market, there are some offerings: The Sony FDR-AX1 is large and expensive, but you can buy it now. There is also a less expensive Sony FDR-AX100 expected to ship in March. And from JVC, the GY-HMQ10. All of these have fairly small sensors, though, compared with the Lumix GH4.

Camera	Form factor	Sensor size	Crop factor	Max FPS	Price	Available
Sony A7s	DSLR	Full Frame	1.1	30, needs external recorder	$2.500	September 2014
Canon EOS 1D C	Large DSLR	APS-H (4K mode)	1.5	25	$12.000	Now
Blackmagic Production Camera	Compact, tripod mounted	Super 35mm	1.5	30	$3000	February 2014
Lumix GH4	Small DSLR	Four Thirds	2.5 (4K mode)	30	$1900	May 2014
Lumix FZ1000	DSLR like superzoom	1''	3	30	$900	June 2014
Lumix LX8	Premium Compact	1''	3	30	$800	August 2014
Sony FDR-AX100	Small Camcorder	1''	3	30	$2000	March 2014
Sony FDR-AX1	Camcorder	1/2.3''	5.2	60	$4500	Now
JVC GY-HMQ10	Camcorder	1/2.3''	5.2	60	$5000	Now
GoPro Hero 3+ Black ed	Action camera	1/2.5''	5.7	15	$400	Now

Shortly after Panasonic announced the Lumix GH4, Blackmagic said it would ship it's "Production Camera", which is 4K capable. It is going to be sold at USD 3000, 25% less than originally announced. It has a Canon EF mount capable of electronic aperture control. Compared with the GH4, you get a slightly larger sensor, but a much less ergonomic camera body. It essentially must be tripod mounted. You also lose the autofocus, compared with the GH4.

The Sony FDR-AX100 is probably the closest competitor to the Lumix GH4, with a similar price, and a slightly smaller sensor. It comes with a non-interchangeable lens, though, and cannot use the host of Micro Four Thirds and legacy lenses that you can mount on the GH4. Choosing between the Sony FDR-AX100 and the GH4 comes down to what type of camera body you want, and whether you want to be able to change lenses or not.

The Sony A7s was announced in April 2014, and offers 4K video from a Full Frame sensor, almost without any cropping. You lose some pixels on either side, bringing the crop factor to approx 1.1. The downside is that it does not record 4K video internally, you need an external HDMI recorder, like the Atomos Shogun, priced at around US$2000, to be available around the end of 2014.

One of the reasons why Sony used a 12MP sensor on the Sony A7s is just this: To be able to do 4K video with very little cropping. Had they used their 24MP sensor, they would have needed to record 4K video off the centre 8MP portion of the sensor, or to sample the 4K video from individual pixels in a grid off the sensor surface.

Cropping has negative side effects, of course, and the sampling can lead to line skipping artefacts. A quality down scaling from a larger resolution sensor to 4K video is very computer intensive, and cannot be done in real time by any consumer camera with todays technology level. That is one of the reasons why they chose a low resolution 12MP sensor for the Sony A7s.

More recently, Panasonic announced the Lumix FZ1000 bridge superzoom camera. With a one inch sensor and a healthy 24-400mm equivalent zoom lens, it is designed to go head to head against the Sony RX10. The Lumix camera sells at a lower price, and has the 2014 must have feature, 4K video.

We also expect Panasonic to release their new premium compact camera Lumix LX8 in July 2014. It will also have a one inch sensor, and features 4K video. Just like the predecessor Lumix LX7, it will have a fast zoom lens.

Conclusion

The Lumix GH4 is a game changer. It is still the only 4K video capable mirrorless interchangeable lens camera. It is very ergonomic, compact, and cheap. Also, there is a healthy lineup of native lenses, plus a host of legacy lenses that you can use with an adapter.

All of this makes it the perfect camera for serious amateurs and indie movie makers.