on April 20, 2015
I had intended to "upgrade" my Olympus E-M1 with the Panasonic GH4, but it didn't quite turn out that way.
My main reasons for wanting to switch to the GH4 were:
1) For my style of shooting, a fully articulated LCD is more useful
2) The new firmware update gave the GH4 the 4K video/photo mode
The truth is, right after I got the E-M1, the GH4 came out and I've off and on wondered if I got the right camera. So after almost a year of using the E-M1 (which I actually really like, except for a few things such as the lack of control during video recording such as exposure compensation, shutter, aperture, etc, and lack of fully articulated LCD), finally pulled the trigger and got a GH4 (with the 12-35mm f/2.8 Power O.I.S.).
Although I knew Panasonic's Power O.I.S. isn't as good as the IBIS of Olympus, I wasn't prepared for the vast difference I saw between the videos I shot with both cameras. The E-M1 videos are so much better stabilized in comparison to the jittery and shaky video from the GH4. And yes, I did check to see if the Power O.I.S. was indeed working (by turning it off and comparing the result), and with it turned off, it's far worse, so the O.I.S. is definitely working, just not nearly as well as IBIS. This is the biggest deal breaker for me at the moment.
The reason why this is a deal breaker for me, is because I shoot a lot of casual/home videos of my wife, and it's all done in run and gun style, such as us walking around while out shopping, or me following her around the house as she goes about her day being her adorkable self. With this style of shooting, I need excellent image stabilization or else the videos end up being too shaky and uncomfortable to watch (headache-inducing). I do not want to use any kind of steady-cam rig because that defeats the purpose of having a MFT camera as the light-weight and smaller complement to my bulky and heavy 5D Mark III.
I wanted the GH4 for a couple of other reasons--fully articulated LCD, and the ability to control exposure compensation during video recording. And yes, I do like those features on the GH4, although it's a little disappointing that exposure compensation only works when you switch the dial to Creative Movie shooting mode and is not available in the other modes. That means if I'm shooting photos and then want to shoot a video, I have to remember to switch to the Creative Movie mode in order to access exposure compensation during video recording, and if I forget to do that and just press the red record button, I'll have to stop and switch mode and then restart recording. So considering that, I don't know if it's actually much better than me using the E-M1 and changing the metering mode to center-weighted metering or spot-metering before pressing the record button (which gives me a similar result as using exposure compensation, when the subject walks in front of a brightly lit window or doorway and I need the expose the subject correctly).
As for the fully articulated LCD, I find that when we're out walking around, the tilting LCD of the E-M1 is good enough, because if I flip it up into horizontal position and holding it at roughly shoulder height, I can see it pretty well when I'm walking next to her and shooting her with the camera pointed to the side and me walking forward, or even me walking in front of her and pointing the camera behind me at her. It's really only in very specific circumstances where I have to be in the shot that a fully articulated LCD becomes necessary. Situations like that are quite rare, and it's definitely not as important as having good image stabilization. And when at home, if we need to record videos that have both of us in the shot, I'd rather just use the Panasonic X920 camcorder for situations like that (though it's not as convenient to have to grab another camera for specific needs).
Another reason I wanted the GH4 was to use its 4K photo mode feature, but it turned out that it not as easy to use as I had hoped. First of all, having to go through the video and find usable frames is extra work that's much more tedious than going through photos, because so many frames are extremely similar, and slight motion blur might make one specific frame sharper than the others, and the process of finding that ideal frame is very time-consuming. Then, there's the issue of only getting a JPG from the frame instead of the more robust and and flexible RAW file. And finally, the 4K files are massive and fills up hard drives quickly (if you shoot a lot of them). I suppose you can extract the stills you want from them and then convert to 1080p, but that's yet another extra step, and once you do that, you can't go back, and in the future when everything's 4K, you'll miss those 4K files.
In comparison to shooting 4K photo mode, shooting high-speed continuous stills will end up taking up a lot less storage space, since you can find the shots you want and delete the rest, but you don't end up with a video you can keep though, and must shoot the video separately, which means it'll be extremely difficult to decide whether a special moment should be recorded with video or photos. I just don't know if it's better to shoot the videos separate from photos but potentially miss shots of footage, or just don't think about it and shoot 4K video by default and then deal with extracting stills and large file sizes and not having RAW files to work with.
Another thing I noticed with 4K photo mode on the GH4, is that its usefulness is only limited to situations where the needs of good photos and good videos intersect, and it's more common to have those situations in professional photography than casual home video/photo--especially when so much of home video/photos are in low-light environments. The video compression and extracted jpg's just have this brittle look compared to RAW files when the ISO is higher. In very well-lit environments, the 4K photos look much better--as good as the RAW files. I think in brightly lit studio shoots, or sports, kids and pets playing in sunny daytime, is where the 4K photo mode will be really useful.
In the end, I decided to return the GH4 and continue to use the E-M1 (along with my Canon 5D Mark III and Panasonic X920 camcorder), since the disappointing image stabilization of the GH4 during video isn't something that will be fixed in a firmware update, and I shoot just as much video as photos nowadays, and they're all run and gun styled home videos. The E-M1 is just so much better at image stabilization, and I don't need broadcast quality for home videos, so GH4's superior image quality and video features don't really mean much for my needs. With thasaid, if I were to shoot a professional project, then I would definitely pick the GH4 over the E-M1.