GH4 Moiré Tests: GH4, GH3, and a Hacked GH2

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Benjobe

Well-known member
I made a simple demonstration of the moiré for the GH4, GH3, and the hacked GH2. I will let everyone draw their own conclusions based on the video. It's going to blow your shirt off.


I used a 1080 24p timeline in Premiere Pro and downscaled the 4K clips by 50%. The original upload file is available for download.

I used a Voigtlander 25mm with the same focus, f5.6, and Tiffen Variable ND filter on each camera. I used the same locked-off tripod position for each. I used the same shirt for each too! I subtly panned each camera left and right for each test. The variable picture profile settings are displayed in the video. The constant camera settings were:

GH4: Highlights/Shadows flat curve, i.Dynamic Standard, Lumen space 0-255
GH3: i.Dynamic Off
GH2: Flowmotion v.2 100Mbps
 
Ben,

When you look at the 4K GH4 footage at full resolution do you see any moire in the shirt ? ( if you don't own a 4K monitor, you will have to crop to view with a 1:1 pixel ratio )

Without being able to view the original 4K footage, I expect the GH4 4K will be close to flawless when viewed at 1:1 pixel ratio when it comes to evaluating moire.
 
Absolutely brilliant test.

FYI, just got off a helicopter where I was shooting 4k with 11-16 and speedbooster (picked up last week). Nice and wide and the rolling shutter was not an issue at 11mm.

Back to your test. I've been saying for a while, there's still something special about the hacked GH2 re moire. Way better than GH3 and still better than GH4 in 1080 mode as well. I can see running around with the wide on the GH4 at 4k and the tele on the GH2. The question is getting them to match in post. I'm sure many will be testing such things in the coming weeks.
 
TheDingo said:
Ben,

When you look at the 4K GH4 footage at full resolution do you see any moire in the shirt ? ( if you don't own a 4K monitor, you will have to crop to view with a 1:1 pixel ratio )

Without being able to view the original 4K footage, I expect the GH4 4K will be close to flawless when viewed at 1:1 pixel ratio when it comes to evaluating moire.
Click to expand...

The GH4 is as clear and moire free pixel to pixel as the GH3 in extended tele mode, if you have that to compare. It's clean as a whistle, really.
 
Cosimo Bullo said:
The GH4 is as clear and moire free pixel to pixel as the GH3 in extended tele mode, if you have that to compare. It's clean as a whistle, really.
Click to expand...

The beauty of grabbing a 1:1 pixel readout from the sensor and a reason I am so very glad Panasonic made the decision to grabe 4k this way instead of pixel binning the entire sensor.

For those who do not have a GH4 you could do this by shooting extended tele on the GH3 and converting to 960x540 in post. Will have the same basic effect of what is going on with the GH4. Except smaller of course. This will give the rest of you an idea of just how clean the image can be and how good the down conversion process can be.

It really is too bad Panasonic doesn't just make the sensor 4096x2160. I think the stills would still be very good at that resolution. Not the best but that is still a lot of pixels. Here's to hoping we can get a 8192x4320 sensor for the GH5 so we can have a true 2:1 readout for 4k recording or a 2:1 extended tele mode for 4k at 1:1.
 
Nice tests, thanks! I've been particularly curious about the moiré and aliasing on the native 1080p modes on the GH4, and I think you've pretty much answered it. After running through the video twice, it looks to me (comparing only the 1080p modes) like the GH2 is best, GH4 second, and GH3 third. Surprisingly (to me at least), it's not a super dramatic difference between the three. I was expecting the GH2 to have no moiré.

By the way, what tripod did you use? Those pans seemed pretty smooth. :)
 
TheDingo said:
Without being able to view the original 4K footage, I expect the GH4 4K will be close to flawless when viewed at 1:1 pixel ratio when it comes to evaluating moire.
Click to expand...

You're right on the money. And I can't believe that I didn't think to include it from the get go. I just updated the video and it has a 100% 4K comparison near the end. I hope that it's helpful.
 
Cosimo Bullo said:
I've been saying for a while, there's still something special about the hacked GH2 re moire. Way better than GH3 and still better than GH4 in 1080 mode as well. I can see running around with the wide on the GH4 at 4k and the tele on the GH2. The question is getting them to match in post. I'm sure many will be testing such things in the coming weeks.
Click to expand...

The hacked GH2 still has a solid role to play in my productions too. I think it's impressive that such an old camera can still hold its own against the current crop of contenders.
 
Shenan said:
By the way, what tripod did you use? Those pans seemed pretty smooth. :)
Click to expand...

That was the Manfrotto 504HD head. It's been a real workhorse for me. Smooth, durable, and dependable. If I have to do long telephoto work (concert, play, etc.) I'll use the 509HD head which is smoother and handles heavier loads.
 
Benjobe said:
That was the Manfrotto 504HD head. It's been a real workhorse for me. Smooth, durable, and dependable. If I have to do long telephoto work (concert, play, etc.) I'll use the 509HD head which is smoother and handles heavier loads.
Click to expand...
Cool, thanks for the info!
 
What puzzles me is why the moiré is so bad on the GH4 in 1080 mode. The crop factor is different between 4K and 1080 mode too. Is there a connection? Anyone know?
 
Benjobe said:
What puzzles me is why the moiré is so bad on the GH4 in 1080 mode
Click to expand...

The GH4 shoots 4K at essentially the sensor resolution, so very little processing has to take place to record the 4K image. It's the down-scaling from full sensor size to 1080 that is causing the moire.

The solution for moire-free 1080 images is to ALWAYS shoot in 4K, and down-scale to 1080p in post. I've done a few tests and was easily able to produce flawless moire-free 1080 images from the 4K footage.
 
Benjobe said:
What puzzles me is why the moiré is so bad on the GH4 in 1080 mode. The crop factor is different between 4K and 1080 mode too. Is there a connection? Anyone know?
Click to expand...
It's definitely there, but I find the moire on the GH4 at 1080p to be slightly better than the GH3 moire. Of course, the moire at 4K is virtually non existent.

Fantastic test!
 
TheDingo said:
The GH4 shoots 4K at essentially the sensor resolution, so very little processing has to take place to record the 4K image. It's the down-scaling from full sensor size to 1080 that is causing the moire.

The solution for moire-free 1080 images is to ALWAYS shoot in 4K, and down-scale to 1080p in post. I've done a few tests and was easily able to produce flawless moire-free 1080 images from the 4K footage.
Click to expand...


Or shoot in Ext Tele mode, no moire there either and looks quite good at 1080.
 
TheDingo said:
The GH4 shoots 4K at essentially the sensor resolution, so very little processing has to take place to record the 4K image. It's the down-scaling from full sensor size to 1080 that is causing the moire.
Click to expand...

Do you think that is something Panasonic could fix with a firmware update?
 
Benjobe said:
Do you think that is something Panasonic could fix with a firmware update?
Click to expand...

I really have no idea. In theory it might be improved with a firmware update, but only Panasonic knows if it's possible or not.

This doesn't bother me much as I already planned on shooting everything in 4K and doing the down-scaling in post, so moire should be completely invisible by shooting 4K.
 
TheDingo said:
This doesn't bother me much as I already planned on shooting everything in 4K and doing the down-scaling in post, so moire should be completely invisible by shooting 4K.
Click to expand...

This will be my method as well. Not only does it produce less moiré but the noise is finer as well and less noticeable.
 
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