Even with a monitor that is less than 1080p I can see a gigantic difference between 1080p @ 60 FPS and 4K @ 30 FPS. It just simply isn’t even close.

One of the things I am really looking forward to is cropping the 4K to 2.7K and doing software image stabilization on it. The resulting 2.7K video will still have more resolution than almost all displays can render.

However, the extra crop factor makes the 35-100mm F2.8 a lot less desirable. It is still wonderful for stills. However, I really wish I had the 12-35mm F2.8 lens now. That lens would be better with the GH4 for the things I shoot now.

Auto ISO in Manual mode has changed the way I shoot stills. I had to resort to Shutter Priority with Auto ISO for indoor sports before. That left me with no way to control aperture. Now I have switched to Manual with Auto ISO and I gained aperture control.

I still wish they would let m4/3s have the Program priority mode from their LX7. That camera allows a minimum shutter speed for Auto ISO.

PLEASE, PLEASE, PLEASE, Panasonic add the Program Priority Auto ISO min shutter speed with a firmware update. I love that you added Auto ISO for manual mode. That works best for an experienced user.

However, I want to be able to hand my camera to a novice and say “Don’t touch any buttons. Just point and shoot and hold the shutter button down till I tell you to stop”. I need the minimum shutter speed settings because 1/60 of a second is just too slow when I have wider angle lenses on there. The camera is rock solid up to ISO 12,800. Let that ISO go up into the stratosphere so we can have more appropriate shutter speeds.

They also took away the Flicker reduction setting from the stills mode. I used that to fix my shutter speed to 1/120 in videos while in stills mode. It worked perfectly on the GH3. Please add this back.

I know the new synchro scan function does a better job but that only works in creative video mode. We really need both.

I did further testing of GH4 with various class 10 cards (Sandisk 64 GB 95MB/s, Sandisk 32GB 30MB/s, and Transcend 64GB SDXC I believe to be 20MB/s). I mounted the camera on the tripod and zoomed at the TV screen using Panny 14-140 lens. I tried various combinations of MP4 (LPCM) and MOV modes with different Rec Qualities including 4K (30p, 24p) FHD 200-I (60p, 24p, 30p), FHD 100 (60p, 24p, 30p). I recorded clips ranging from 10 - 20 minutes (specially 4k and 200-I for 20 minutes). All tests worked with no failures and spanned multiple times. Class 10 cards look promising.

Think of it this way. 100 mb/sec video is 12.5 MB/sec. All class 10 cards are rated for 10 MB/sec. It would be very rare that a true class 10 card could not write at 12.5 MB/sec when it is guaranteed for 10 MB/sec. All of the class 10 cards I have write at 18 MB/sec or more in real world tests that I have done.

The only issue would be the 200 mb/sec(25 MB/sec) All I 1080p mode. A lot of class 10 cards won't keep up with that and I had failures with the 200 mb/sec mode last night with class 10 cards.

If you don't use 200 mb/sec All-I you probably won't have any trouble even with class 10 cards.

EDIT: Resolved.

I noticed when I do timelapse in camera that the monitor goes to sleep. Is there any way to keep the monitor on while the timelapse is going? I tried going into the economy setting but didn't see any options there.

I purposely did not buy 128 GB cards because I suspected they wouldn’t work. Therefore, I can’t test them.

Took delivery of my GH4 this afternoon (thanks, Samy's!) and I've had just a little while to get the lay of the land. My overall impression is very positive.

My biggest reasons for upgrading my GH3 were as follows:

1. Improved video features -- primarily 4K and the new Cinelike D profile. Still very early days, but so far these look every bit as good as I'd hoped. FYI, the Cinelike D profile provides much flatter footage than Panny previously offered for wider DR and more latitude for color correction. Need to do more testing, but it also seems as though 4K modes work fine with my older Class 10 SD cards;

2. Focus peaking: I was very disappointed that this never made it into the GH3 and so far I'm thrilled with the way it's working with the GH4. It makes working with fast manual lenses SO much nicer!

3. Zebra stripes: I've always been jealous of Olympus users who had those blinky highlights in record mode as an aid to setting exposure. The zebra display works brilliantly for that purpose;

4. Improved EVF optics: I found the GH3's EVF perfectly useable but still unpleasant due to its very small sweet spot. I'm pleased to report that the GH4's EVF is miles better. Not only is it sharp from edge to edge, but it's also sharper overall. The rear monitor is noticeably sharper, too;

5. Better AF tracking: not a huge deal for me since I don't use it that much, but I found it virtually useless with the GH3 and GH2. In early tests it seems to work very well indeed with the GH4 ... at least for tracking in video. I haven't had a chance to see if it's up to BIF. I don't think it will be as it will probably struggle to acquire such a small target. In terms of straight AF speed, to be honest, the GH3 was perfectly adequate for my needs. The new burst rate is just silly without AFC. With AFC it seems slower than advertised, but I will have to test more;

Random observations:

1. The addition of auto ISO to manual mode is great, but it's limited to stills recording. This seems nonsensical and hopefully it can be addressed in a firmware update;

2. All of the function buttons can now be assigned to any of the available functions. This is nicer than the GH3 where certain FN buttons were limited to a subset of available functions;

3. The movie record button is less recessed than before. I think it strikes a nice balance as I thought it was too hard to activate on the GH3;

That's it for now. In the coming days I'll do some detailed photo/video comparisons to the GH3 and post additional thoughts.

When asked about SD cards in the Zacuto vid, the Pana rep made reference to 256gb options, so hopefully there wont be any limitations in that regard.

Just picked mine up at the shipping terminal. First impressions are in line with comments already made here on PV. The AF is just BEASTLY. The extra focus points are great. I thought it would be difficult to improve on GH3 lock times but this is just ridiculous, instantaneous lock ups - with an Olympus lens!! The viewfinder is super crisp and HUGE... It looks to be about four times bigger to my eyes because the edges are no longer blurred out. Looking forward to running some tests up to and through the weekend.

Hey @mpgxsvcd, can you comment on low light abilities relative to GH2?

Here is a simple GH3 vs. GH4 test. This is Standard color mode in both with Default settings. The difference is that it is IBP 50 mb/sec for the GH3 and 200 mb/sec All-I for the GH4. Not a striaght up fair fight but life isn't always fair.

The GH4 can do it better so that is how I tested it. I would say this is a noticeable improvement even for 1080p.

Some more pleasant test results. I loaded GH4 with a fully charged genuine Panasonic battery and Sandisk 64GB 95MB/s card. I recorded UEFA Champions soccer game between Chelsea and Atletico Madrid from TV using FHD 200-I 60p. Recording continued without any problems until the card was full spanning 14 times and recording 50 minutes with bitrates reanging from 140 - 208 mbits. Surprisingly the battery still had three bars (full). I replaced the card with Transcend 64GB SDXC card and recorded the rest of the game in FHD 100MBS 60p. The card filled up with 1hour and 40 minutes of recording. The battery still showed two bars after 2.5 hours of non-stop recording. That's impressive.

While I'm using Movie mode on a GH3, I try and keep the Shutter Speed at 1/60 (for 30fps) and the Aperture at f5,6-f8. So I use the ISO to keep the exposure correct. On the GH3, when changing the ISO, it turns off the Exposure Meter - is this something corrected on the GH4? If changing ISO - does the exposure meter stay on screen?

@Zaven13 Dude... thanks for all this great info! Any chance you can give details on the disappearing info? Audio meters?...exactly how long and what's still on screen?