GH4 Test show Variable frame rates have different resolutions.

[Ted Ramasola]

I was curious about the soft image when using 96fps so I did some resolution chart test.
I shot the usual chart to be able to compare the various framerates and see if the other framerates are soft as well.
Lens used is a canon24-105 f4L, no speedbooster to remove that equation.
iso are all at 800.
manual whitebalance.


First I shot 4K at 23.976 as a reference.
For FullHD I reframed the chart since 4K has more crop than at 1080p.
Then first HD shot at 200 Mbps to see if the high bitrate improves resolution compared to 100Mbps.
I also shot at 60P.

Then shot VFR from 2fps up to 96fps.

RESULTS,

200Mbps and 100Mbps Full HD shots resolves the same resolution at around 800+ lines. 24p and 60P yield the same result of around 800+.

Then the interesting part, shooting VFR, 2fps up to 60fps yields same result as non VFR fullHD shots, 800+ lines.
starting from 72, 84 and 96 fps is where the degradation occurs. the softness is aggravated and resolution goes down.

Here is a summary chart showing the vertical res.

Here's a summary of the center target.

Go here to see the side by side of all the VFR settings.
https://www.facebook.com/media/set/?set=a.755871411136593.1073741834.312706892119716&type=1

 

[morgan_moore]

Thanks for doing this.

 

[daihard]

Yes, very interesting. Was this all shot at the same frame rate, ISO, aperture - Throughout? I expect so, but just outta curiosity I ask.
I have heard that shooting 96, there is severe morie... so something is going on.

 

[Ted Ramasola]

Thanks for doing this.

Your welcome Sam,

Knowing this, it seems that for mission critical slo mo shots it's best to just stick with 60P rather than go VFR.
The timelapse effect of the low fps settings are useful though.

 

[morgan_moore]

Your welcome Sam,.

Id like to see the same on the A7s.

Sometime I will buy a new small/light gimbal/carmount/steadicam camera to replace my NEX5n.

Been shooting BMC 4k (not mine) recently and feel it is very 'honest' with no HFR of any nature - of course the HFR are a carrot that dangles from the Gh4 over the BMC but to some extent this test rots that carrot!

The bmc gets a step ahead of the GH4 (IMO) if you discount the framerates, having no crop, 'free' SDi, prores, etc.

Im very aware of the FS700 being soft above 60 - which to some extent pushed me to the F3 - which is cheaper than the 700 and has with the right recorder just as high framerate if you actually consider a sharp image.

S

 

[Ted Ramasola]

Yes, very interesting. Was this all shot at the same frame rate, ISO, aperture - Throughout? I expect so, but just outta curiosity I ask.
I have heard that shooting 96, there is severe morie... so something is going on.

At 72, 84 and 96, the moire is not as bad as those found in Canon dslrs, also, there is very minimal to no color aliasing. It is just very soft and low res.

 

[David W. Jones]

Thanks Ted!

 

[wwjd]

awesome thanks! I'm curious how you arrive at the number 800+ (special test pattern?) and if the lens affected resolution.

 

[morgan_moore]

You can see from the 4k that the lens is no problem.

 

[Bern Caughey]

Knowing this, it seems that for mission critical slo mo shots it's best to just stick with 60P rather than go VFR.

Was up late, & the caffeine hasn't kicked in yet, but doesn't your test show VFR up to 60 fps look identical to 60p!?! Typically I prefer VFR so I can immediately check for strobing by reviewing footage in-camera.

And as others stated, thanks for sharing these tests!

Best,
Bern

 

[aljudy]

Nice test and thanks for sharing. This must be a codec issue; I suspect the increased frame-rates degrade the encoding. There are two ways to set the camera for VFR: MOV and MP4(LPCM) but it appears they are both 100Mbps. However I wonder if there is any difference to the encoding (probably not)?

EDIT: Actually VFR can be done with AVCHD also! I wonder how all this affects the resolution issues you highlight here?

 

[Ted Ramasola]

Was up late, & the caffeine hasn't kicked in yet, but doesn't your test show VFR up to 60 fps look identical to 60p!?! Typically I prefer VFR so I can immediately check for strobing by reviewing footage in-camera.

And as others stated, thanks for sharing these tests!

Best,
Bern

Yes Bern, the VFR settings up to 60fps is similar in resolution to 60P non-vfr mode. The benefit of VFR is being able to see it in-camera playback, the advantage of using 60P mode non-vfr is the ability to record in-camera sound, which might be useful in some scenarios.

Definitely, it's not advisable to use 72fps and up when shooting wide detailed scenes when this will be used in an HD or 4k finish. For web delivery, it might be passable.

 

[Bern Caughey]

Thanks again Ted.

 

[hectordsilva]

what will be the max TV lines if 4k down converted to HD

 

[Ted Ramasola]

what will be the max TV lines if 4k down converted to HD

The GH4's 4K image dropped on a FHD timeline should give you more or less 900+ to approx 1K.

 

[Ted Ramasola]

Also, testing how soft 72,84 and 96fps is, I did a chart shot at 1280x720 mode and its still sharper than the high VFR rates 72,84,96.
720p however will introduce more moire that is not found in the high VFR rates shot at 1920x1080.

Center target comparison:

 

[aljudy]

Do you agree that there is no difference in MP4 and MOV? Again, thanks for doing these tests... Al

 

[wwjd]

sweet! Did you post your SHARPNESS setting?

 

[Ted Ramasola]

Do you agree that there is no difference in MP4 and MOV? Again, thanks for doing these tests... Al

Yes, resolutionwise there is non.
I use mov for compatibility across NLEs, MP4 LPCM can't be opened in some NLEs like premiere.

 

[Ted Ramasola]

sweet! Did you post your SHARPNESS setting?

Did all the test in Cine-D at default, meaning all 0 settings.