Comparing them is not entirely fair, though, as there is some age difference. The Sony NEX 3N was released in February 2013, while the GF3 was launched in June 2011. The GF3 has been replaced by the Lumix GF5 in April 2012, and then later by the Lumix GF6 in April 2013.
The GF5 is basically the same camera as the GF3, except that it adds a rubber grip surface on the front, which is actually a big difference. The GF6 is a big improvement, though, with a newer sensor, better ergonomics, and a tiltable rear LCD.
In this article, I compare the video output of the two cameras. Both were set to the base ISO, 1080p, 25fps. I used the Lumix X PZ 14-42mm f/3.5-5.6 at 14mm f/3.5, while the Sony NEX also had the kit zoom lens Sony 16-50mm PZ lens was set to 20mm, to match the field of view of the Lumix lens.
Here is the comparison:
Here are also some still images for comparison:
|Sony NEX 3N||Lumix GF3|
|Sony NEX 3N||Lumix GF3|
Even if the Sony NEX 3N is two years newer than the Lumix GF3, I still find that the GF3 outperforms the 3N in terms of video performance. It focuses faster, it generally exposes better, and has better colours. The startup delay is also significantly shorter with the GF3. The Sony NEX appears to have the upper hand by a small margin when it comes to handling of rolling shutter, but that is hardly a problem with either of them.
I find the same conclusion with the still images: The Lumix GF3 generally exposes better, and I like the out of camera colours better. If I had spent some time editing the images with a RAW converter, I think I would get better images from the Sony NEX 3N, though.
Overall, it is fair to say the Lumix GF3, the oldest model, focuses the fastest by a good margin. This applies during video recording, as shown in the video above, and also for still image use. I found this to be true especially when using the long end of the zoom lens.
Both cameras use CDAF technology for focusing. The speed of CDAF during video largely comes down to image processing power. Hence, it is not unexpected that the premium camera Panasonic GH3 outperforms them both in this aspect. I have tested the AF during video here, and the GH3 performance is very impressive.
Some newer and more expensive Sony NEX cameras feature on-sensor PDAF. This will probably give better autofocus performance. For example, the Sony NEX 5R has this feature. However, the real life benefits of on-sensor PDAF is somewhat uncertain.
The power zoom lever is longer on the Sony NEX lens, spanning a larger part of the lens diameter, so that it can be easily operated both in landscape and portrait mode. That is not as easy with the Lumix X PZ 14-42mm, having only a small lever.
On the other hand, though, the Lumix lens has two zoom speeds, while the Sony lens only operates at one zoom speed. This makes a huge difference, and it is much more pleasant to use the Lumix lens when zooming. Especially when taking still images, it is very awkward and annoying to try to get the desired field of view with the Sony camera, by pushing the zoom lever briefly to get the change you need. On the Lumix camera, just pushing the zoom lever slightly operates the motor at the slowest speed, in which case small and accurate adjustments are very easy to make.
When it comes to video recording, the Sony camera has one clear advantage over the Panasonic cameras: It displays the exposure settings in the display while recording. A very annoying feature of the Panasonic Micro Four Thirds cameras, even the "video optimized" GH3, do not display the aperture, shutter speed, and ISO settings while recording videos. Unless you set these manually, that is. Seeing the exposure settings while recording makes it easier to use the Sony NEX 3N for video, in my opinion.
In general, the Sony camera feels a bit less responsive, perhaps this feeling is magnified by the somewhat slower autofocus, especially with the lens in the longer end of the focal range.
The Sony camera adds a tilting LCD display, which I find very useful. When having the camera in a neck strap, one can keep it at waist level, while looking down into the tilted display. This way, it is easy to achieve stable video recording. With the GF3, one must keep the camera at arm's length in front of the face, where it is quite hard to hold steadily. The newer Lumix GF6 also adds a tilting LCD display, so Panasonic is aware of this problem.
The Sony NEX-3N is an interesting camera, with a large APS-C sensor in a very small body, and a compact and light power zoom lens. I find that it does not operate as smoothly as the older GF3, though, and it does not perform as well when it comes to video colours and autofocus. The camera feels solid, but the lens wobbles a bit when extended. This is in contrast with the Lumix X PZ 14-42mm lens, which is rock solid even when extended.
In terms of pricing, the Sony NEX-3N with the power zoom kit lens is very competitively priced. The lens extends to 16mm in the wide end, corresponding to 24mm equivalent, which is more interesting than the focal length range of the Lumix lens. All in all, the Sony camera kit is quite interesting for people who want to get started with mirrorless cameras at a reasonable cost.