The first obvious things that are different about the GX1 as compared with the GF1 are:- New grip, New viewfinder, Virtual "spirit level".
BODY
The body doesn't feel quite as "metallic" as the GF1, but its certainly well put together. The silvered retro look is very nice and the grip is OK. Lets just say its better than the G3, but the enthusiasm for it in other reviews I've seen, isn't something I'd share.
Its well endowed with knobs and buttons and seems well laid out, though I haven't used it in the field as yet. Certainly its a different looking and handling camera to the GF3. It will be very familiar to Panasonic GF1 users, and while people may not like the fact that a few things have been moved around, there's certainly nothing that I anticipate as being a real problem. If some operational problems crop up, I will of course report on that.
VIEWFINDER
At last!!! A decent add-on viewfinder for a Panasonic camera. It does work very well, and seems very similar to the G series EVF's and the Olympus VF-2. The usual problems with low light and its not as good as the Sony OLED viewfinder for the NEX-5n. However it has one great feature. It actually locks into its socket properly and doesn't keep working free all the time. This irritates me a lot on the Sony and on the Olympus Pens. Yes it moves into a vertical position, but it has a release knob which moves this from the horizontal position. It is possible to move it upwards without using this, but it takes a fair amount of effort. I'm assuming it wont move by just putting my eye and forehead to it, and certainly that hasn't happened so far.
Its not OLED, but its just about usable with polaroid sunglasses, as is the screen.
VIRTUAL SPIRIT LEVEL
Very nice. A great feature for us landscape and architecture photographers. Its switchable on and off with a display or function button. Like on my Sony a77, I will probably have it on all the time.
So thats all good.
In terms of image quality change from the GH2 / G3, its pretty similar. Panasonic are constantly tweaking their sensors and there are some small improvements. There is still the incidence of luminance noise at all ISO's, even ISO 160, but there does seem to be a slight imrovement in the upper ISO performance. Unfortunately the jpgs. from 3200 to 12800 are pretty terrible. Smeared and basically quite unpleasant. Somewhat similar to what Samsung have chosen to do with the NX200. Raw however isn't too bad. Here's a couple of examples.
For larger versions click on image > flickr > Actions > View all sizes > Original
Here's one of the ISO 6400 files above with my own noise reduction appplied to a raw file in Photoshop. Somewhat more to my taste than the jpgs.
All in all this isn't that bad, and somewhat astounding to those of us who bought and used a G1. This is not Sony NEX levels of high ISO performance, and of course a long way short of Nikon and Canon full-frame DSLR results, but its now got to a state where its reasonable and the criticisms that could be levelled at m4/3 in this area aren't applicable any more. If you are a heavy duty low light photographer then you'd be using something else anyway, but for those times when its needed, it will produce a viewable image. However I would recommend using raw for this. If you don't have a fast lens that is, which is always my preferred option.
On first impressions it seems a nice upgrade. If you liked the GF1, then I would be surprised if you didn't like the GX1. I've been using m4/3 for so long now that I'm used to the system, how it works and the results it comes up with.
For my own use, I'm wanting to use this mainly with the 20mm f/1.7 lens. Despite trying most of the m4/3 lenses, including the excellent 25mm f/1.4 and the Olympus 12mm f/2 and 45mm f/1.8, the lens I love more than than any other is the little Panasonic pancake lens. These days its not quite the sharpest or the fastest, but there's something about the focal length and the overall look of the files that I really like. I'm definitely in one of my going out with one prime lens phases, and I've always enjoyed my excursions with the 20mm. My new (and fourth!) copy is arriving today, and if and when the sun comes out I'll be out trying the combination.
I'll post some more thoughts and experiences in the days to come, and certainly if the weather is as dull as it is today, I can see myself doing some comparison tests with the NEX-5n and NX200.
As far as I'm concerned, the GX1 is easily Panasonics most "stylish" camera, though I'm not sure thats saying much! Its nice to see that they have decided to pander a little to us "retroheads", even though it took a while. With small cameras I'm much happier with this rangefinder style design, and having handled the GF3 this is much more to my taste. Despite all my positive feelings about the NEX-5n, I still get a great sense of enjoyment from using m4/3 cameras, though despite my love of it as an artefact, the Olympus E-P3's 12MP and IQ just wasn't enough, despite my attempts to persuade myself that it was! At low ISO's the GX1 will produce great images, I'm sure, and despite the advantages of the Sony NEX system, this Panasonic sensor has the better colour for what I do. I wanted to like the GX1, and I do, and if you like m4/3 then do have a look at it. If you like the system already, then I don't think you'll be disappointed by the new kid on the block.