GH3 GX7 thread

kuyagreg

New member
Hi all!
Does anyone have any experience filming with the GX7? It seems very similar to the GH3. Would appreciate any advice on getting the best quality footage from this awesome camera.

Thanks,
Greg
 
There is no mic input and no headphone jack but that's no problem really unless you're one man banding it and working to a tight schedule. Oh, and it's not weather sealed either, so not ideal if you also have weather sealed lenses and tend to brave harsher environments.

Besides that, I think the GX7 is better in every way. It's nice and small and looks sexy (especially the silver version). I feel like a rock star using it.

It can do 50/60P. It has better resolution, so less moire and aliasing. It has better dynamic range retaining highlights better. It can shoot at about two stops better (ISO 3200 is cleaner as the EOSHD tests also prove). Despite the GX7 recording in a lower bitrate, it compares favourably to the ALL I on the GH3. I haven't noticed any major compression issues and the smaller file sizes are better. I prefer adding in a little extra grain anyway to disguise the 8bit ness and compression.

I would also suggest shooting in AVCHD and not MP4. The AVCHD is at 24Mbs but is in High Profile and has CABAC. The mp4 is only Baseline profile, and despite claiming it is 20Mb, it seems to record 3x less bitrate on average than the AVCHD and the grain quality looks more stiff/blotchy.

By default, the contrast and sharpness is probably a notch higher on the scale than the GH3, so you may wanna lower it down to avoid the over baked in look.
Enjoy!
 
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I just returned from Samy's camera in San Francisco, and it's clear after doing a couple of AB tests with my GH3, the GX7 has a much wider sensor. Possibly wider than the GH2's, 1.86 crop. Does anyone have any more knowledge about this? I'm not finding much on Google. This is great news, as I often feel I'm just not getting wide enough with my 14 to 140 on the GH3, but I do need the long lens. Also, the GX7 seems head and shoulders better than the GH3 in lowlight and seemingly much better with aliasing as well.
 
Going to head back to Samy's later today or tomorrow and will bring a GH2 to compare with. I have to say, that little bit of extra width on the wide end has really been tough to live without with the GH3 (which I love, BTW, mostly for the great looking 60p).
 
What did you find? I didn't notice my GX7 looking any wider than the GH3 though?
 
I find GX7 to be a superb B-Cam.
It is a "day to day I have you with me all the time" photo/video cam.
I treat it as a training camera of some sort as well. The fact that you have it with you all the time makes you shoot so much more and you end up experimenting with subjects and ideas you normally would not it. Dress it up with a Fotasy 35mm 1.4 C mount "Idiot" and you have got yourself a best friend:)
Ergonomics, size, screen, ok battery life , 60P and wifi all amount to its attractiveness. It does seem to outperform the GH3 in lowlight also. The fact that you can set your curves also helps. It will probably drop down in price to 500$ by the summer.

Little tests I have shot with it.

https://vimeo.com/82816678

pass:12345

https://vimeo.com/79528623

pass:12345

https://vimeo.com/79773157

pass:12345
 
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@Lammy - for sure the GX7 is wider, very close to the GH2 in video mode. However, it seems the camera only uses this part of the sensor in video mode, not in stills mode, and so it's not referred to as a multi aspect radio. Strange undocumented feature. - I'm in no man's land: Have the GH2, GH3, C100.... have an order in for the GH4 with Samy's (they had me put 10% of what they thought would be the price of the camera). I did go back for another test and for sure there is less moire/aliasing on the GX7 than GH3. I'd say similar, possibly slightly better than GH2. Black are clean and nice. But when I really 'peep' the footage, the codec does seem to break up more than on the GH3. Everything is a compromise in one way or another (size, weight, shooting comfort, res, latitude, etc, etc, etc), right?

Also, the GX7, for those who haven't handled it, just feels lovely in the hand, elegant design.
 
Cossimo Bullo : Good point about the codec breaking up.
I guess the lower bitrate when compared to the GH3 has to show its face somewhere.

There is one puzzling white balance issue I am noticing.
Whenever I press record the WB value I have set or at least its preview on screen shifts to a slightly warmer tone.
So let's say when in Custom WB mode, I set my balance to a value which corresponds with my reading, then I press REC and the display turns slightly to a warmer tone.
I also own a GH3 and it does not do that.

Cossimo have you noticed such behaviour with yours ?
Or anyone else for that matter ?
 
Whoa- if this has the multi-aspect ratio for video like the GH2 did, that would be HUGE! Anyone have access to these bodies that can do some comparison shots using the same lens? I'd love to see how the FOV differs between the GH2, GH3 and GX7.

I've been considering replacing my GH2s with the G6 because of the 60p and in-body peaking, but was sad to hear that despite using the same sensor, it does not go wider in video mode. I figured the GH2 was just going to be the first and last with that awesome perk. If the GX7 does it, I'm really going to be leaning towards this going forward.
 
Yeah I've noticed there's a colour shift when pressing record, very similar to the issue the GH2 has.

I don't have a GH3 or GH2 at hand to compare right now. Though my friend has a GH2 so in the next few days I could pop around have a look.

GX7's video mode simply crops the top and bottom of the still image (I can confirm this by just flicking the mode dial from stills to video). If it is wider, then that effects stills too?
 
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Yet another procrastinating GX7 test. Might come in handy for someone considering the purchase.
This time around a Sigma 28mm 2.8 was used.
I like the feel of this lens on the GX7. A bit of hazy soft look combines well with sharp quality of GX7 video.

https://vimeo.com/88725120

pass:12345

cheers
 
Awesome work dude! Do you change the curves on the GX7 at all on these vids?

I got a little scared using the fujian c-mount lenses. I recently bought the 35mm but the adapter that came with it almost got really stuck on my GX7 mount. Since then haven't really tried using it, tempted to look for ways to keep the adapter always fixed to the lens itself.
 
Lammy, yep, I have -2 hightlight , +2 shadow curve set up at all times pretty much.
Gives me a flatter look from the box.
 
Pulled the trigger on a GX7 today. So far, really loving the overall look of the footage. I didn't realize there is no 30p 24/28mbps mode. So it's 60p 28mbps all the time, I suppose. That's what I've ben using most of the time with the GH3. Truly amazing how much sharper the viewfinder is than the GH2/3/G6.

Quick question: Have we decided, is there a difference in quality between AVCHD and MP4 at the same bitrate/framerate. Or is that just a wrapper?
 
Quick question: Have we decided, is there a difference in quality between AVCHD and MP4 at the same bitrate/framerate. Or is that just a wrapper?

Unless the GX7 is an exception, I'm pretty sure the AVCHD and MP4 internal codecs are handled very differently by the camera.

I'm really itching to get a GX7 now, but I keep eyeing the GH4 around the corner.
 
The AVCHD is at 24Mbs but is in High Profile and has CABAC. The mp4 is only Baseline profile, and despite claiming it is 20Mb, it seems to record 3x less bitrate on average than the AVCHD and the grain quality looks more stiff/blotchy.

Very different implementation of the codec aye.

Did ya manage to see if your GX7 was wider in crop than GH3?
 
Yes, it is slightly wider than the GH3, slightly less wide than the GH2 (have all three here to test). But that extra 1mm (or something close to that) does make a difference.

The main thing is that the sensor is clearly in another world compared to the GH3 in low light, and aliases MUCH less than the GH3 in all light. Also, the curves in camera are great with shadows and highlights, and the ETC mode, which works in 60p unlike the GH3, seems considerably cleaner.

Can anyone elaborate more on the various modes of 60p (AVCHD vs MP4)? Shooting with it tomorrow and need to pick a setting.
 
BTW, I was wrong, there is a 30p 24mbps mode in the AVCHD settings.

Also, just did the same shot with 60p in AVCHD and MP4 and I can't see any difference between them for what it's worth, even in the sky.
 
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Ooh interesting so it's only a few mm crop difference? Coupled with a small body seems like a great advantage.


You're right - I just did a test at 50P (I have the PAL version so don't have 30/60) and I can't see a difference either.

Unlike the 25p, it turns out the 50P of the AVCHD and the MP4 use the same encoding implementation?


MP4:
Format : MPEG-4Format profile : Base Media / Version 2
Codec ID : mp42
File size : 32.9 MiB
Duration : 9s 600ms
Overall bit rate mode : Variable
Overall bit rate : 28.7 Mbps
PANA : DMC-GX7


Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.2
Format settings, CABAC : Yes
Format settings, ReFrames : 2 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 9s 600ms
Bit rate mode : Variable
Bit rate : 27.2 Mbps
Maximum bit rate : 36.9 Mbps
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 50.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.262
Color primaries : BT.709-2, SMPTE 274M, SMPTE 296M
Transfer characteristics : BT.709-2, SMPTE 170M, SMPTE 274M, SMPTE 293M, SMPTE 296M
Matrix coefficients : BT.709-2, SMPTE 274M, SMPTE 296M


AVCHD 50P

Format : BDAV
Format/Info : Blu-ray Video
File size : 34.4 MiB
Duration : 10s 161ms
Overall bit rate mode : Variable
Overall bit rate : 28.2 Mbps
Maximum Overall bit rate : 28.0 Mbps


Video
ID : 4113 (0x1011)
Menu ID : 1 (0x1)
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.2
Format settings, CABAC : Yes
Format settings, ReFrames : 2 frames
Codec ID : 27
Duration : 10s 100ms
Bit rate mode : Variable
Bit rate : 26.9 Mbps
Maximum bit rate : 26.5 Mbps
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate : 50.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.260
 
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