GH4 Is the V-Log quality comparable with the Blackmagic Pocket Camera dynamic range?

R

rc444

Well-known member
Is the V-Log plug-in on the GH4 comparable or on the same level as the dynamic range on the Blackmagic Pocket camera?

This question is assuming you use a Shogun on the GH4 so you can match the 10 bit on the Pocket camera.
 
It's close, but hard to quantify because the exposure distributions are so different. I own a GH4 with the V-Log plugin, but I still give a slight edge to the pocket cam.
 
I'm actually looking at replacing my GH4 with the BMPCC because I just can't seem to get a clean image out of my GH4. Even at a lowly 400 ISO, the image is just fugly when pixel peeping. I'm so accustomed to the superb Moon Trial 7 image from my hacked GH2, and the GH4 so far hasn't met that standard. It looks like the BMPCC's RAW mode will exceed.
 
I guess it is all in the eye of the beholder. I have used the GH4 since it first came out and have not noticed any problems under 1000 ISO.
 
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Two things that make the GH4 image cleaner are lowering sharpness to -3 to -5, and NR to -5. I try to shoot at ISO 200 whenever possible, which with fast lenses usually isn't hard, but I shoot mainly dramatic stuff where lights are used. One thing I am noticing at ISO 200 is that the highlight roll off is much nicer than the supposedly native 800. 800 and above the highlights clip more harshly.
 
Interesting. I own both cameras and I am constantly going for my GH4. the bmpcc image is definitely FAR superior to the gh4, however the images I've taken on the bmpcc are constantly ruined by moire.
 
Mark Williams said:
I guess it is all in the eye of the beholder.
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That is one possibility. I might just be spoiled by the superb image created by Nick Driftwood's Moon Trial 7 hack. I mean, it was an outstanding image.

Even at a higher bitrate, I can't get the GH4's quality to match.
 
Jim Simon said:
1080, 200 Mb/s All-I.
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The 200mbps mode is still 8bit, 4:2:0 and H264 based. While it may use whole frames as part of the encoding that is about all it has over regular H264. Plus the HD mode on the GH cameras while amazing compared to a lot of other HD DSLR cameras is not a perfect down conversion.

Shooting 4k and down converting in post yields far superior quality. You in essence get HD that is a perfect clean down conversion, 4:4:4 and free of many of the compression artifacts as part of the down conversion. If that still isn't good enough the GH4 will down convert the 4k sensor to HD via the HDMI port to a external HD recorder. You can get an Atomos older HD recorder for $295 which gives you 10bit ProRes422 HQ which is similar to the recording format of the BMPCC (minus raw of course). Even if one doesn't have external 4k in the budget it is extremely cheap to record external HD that is vastly superior to the 200mbps GH4 mode. This external HD combined with V-log is a pretty darn amazing gradable HD image. external 4k is amazing but external HD is not bad at all especially if you normally edit and deliver in HD. You are already getting some of the 4k advantage of the sensor by going this route.

Just be aware that the HDMI down conversion uses a nearest neighbor form of scaling which can yield some extremely fine detail. I sometimes slightly blur in post if it is too much. Shooting with a -5 sharpness helps a lot. Shooting with adapted lenses helps even more. It isn't a mathematically perfect down conversion since it is nearest neighbor but it looks a heck of a lot better than internal with V-log. Nearest neighbor would normally be a horrible way to down convert an image but in one case it actually works fairly well. An exact 1/2 scale which is what the GH4 does with 4k to 2k.

Also check out the Atomos Ninja Blade. This is their older 1280x720 monitor but it now has the AtomHDR support in the latest firmware. This adds the ability to work with log formats including Panasonic V-log so they look like rec709 on the monitor. You cannot load custom luts but this new update is better than nothing. Best part is it is only $495 which is a pretty darn good cheaper option for 10bit V-log monitoring and recording from the GH4 in HD. HD ProRes422 HQ also works well on 7200 RPM drives so no need for expensive SSD drives. This makes external HD a very affordable option for those that cannot afford external 4k and the huge storage requirements.

HD 24p ProRes422 HQ is also only 176mbps so it is actually smaller in file size to the GH4 200mbps mode so your files will be a bit smaller but visually and mathematically so much better.
 
estarkey7 said:
It's close, but hard to quantify because the exposure distributions are so different. I own a GH4 with the V-Log plugin, but I still give a slight edge to the pocket cam.
Click to expand...


Are you using V-log internal or external? While V-log can be used with the internal encoder it really shines when recording 10bit external. Since the BMPCC records 10bit ProRes422 it is only fair to compare the two cameras with a similar recording format to know what the image block itself is capable of.
 
Thomas Smet said:
The 200mbps mode is still 8bit, 4:2:0 and H264 based. While it may use whole frames as part of the encoding that is about all it has over regular H264. Plus the HD mode on the GH cameras while amazing compared to a lot of other HD DSLR cameras is not a perfect down conversion.

Shooting 4k and down converting in post yields far superior quality. You in essence get HD that is a perfect clean down conversion, 4:4:4 and free of many of the compression artifacts as part of the down conversion. If that still isn't good enough the GH4 will down convert the 4k sensor to HD via the HDMI port to a external HD recorder. You can get an Atomos older HD recorder for $295 which gives you 10bit ProRes422 HQ which is similar to the recording format of the BMPCC (minus raw of course). Even if one doesn't have external 4k in the budget it is extremely cheap to record external HD that is vastly superior to the 200mbps GH4 mode. This external HD combined with V-log is a pretty darn amazing gradable HD image. external 4k is amazing but external HD is not bad at all especially if you normally edit and deliver in HD. You are already getting some of the 4k advantage of the sensor by going this route.

Just be aware that the HDMI down conversion uses a nearest neighbor form of scaling which can yield some extremely fine detail. I sometimes slightly blur in post if it is too much. Shooting with a -5 sharpness helps a lot. Shooting with adapted lenses helps even more. It isn't a mathematically perfect down conversion since it is nearest neighbor but it looks a heck of a lot better than internal with V-log. Nearest neighbor would normally be a horrible way to down convert an image but in one case it actually works fairly well. An exact 1/2 scale which is what the GH4 does with 4k to 2k.

Also check out the Atomos Ninja Blade. This is their older 1280x720 monitor but it now has the AtomHDR support in the latest firmware. This adds the ability to work with log formats including Panasonic V-log so they look like rec709 on the monitor. You cannot load custom luts but this new update is better than nothing. Best part is it is only $495 which is a pretty darn good cheaper option for 10bit V-log monitoring and recording from the GH4 in HD. HD ProRes422 HQ also works well on 7200 RPM drives so no need for expensive SSD drives. This makes external HD a very affordable option for those that cannot afford external 4k and the huge storage requirements.

HD 24p ProRes422 HQ is also only 176mbps so it is actually smaller in file size to the GH4 200mbps mode so your files will be a bit smaller but visually and mathematically so much better.
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If you record with an older HD Atomos recorder, can you record in 4K, or do you have to record in 1080p?
 
You need a 4K-capable recorder to record 4K.


Intraframe compression (the GH4's 200Mb/s 1080 modes) is always much much less efficient than interframe compression (IPB/all other modes on the GH4). If you don't have an outrageous amount of motion happening in your shot, the GH4's 200Mb/s intraframe mode is best reserved for the rare cases where motion integrity becomes more important than outright detail/image cleanliness (so, lots of motion happening all at once).


Personally, much of my personal shooting (action-sports followcam with a fisheye lens- so a deep DOF with the whole frame moving quickly) lives exactly in this rare region, so I find the 200Mb/s useful, but for anything approaching "normal" shooting (or even action shooting where the frame isn't moving or is moving slowly/predictably in a pan/tilt/dolly/etc), the 100Mb/s IPB 1080p60 mode is better/cleaner/more detailed. And if I know I won't need to slomo the clip I always go to 4K, which of course looks even cleaner still.
 
Unless you really must have 60p for HD it is a much better solution to shoot in 4k mode in the camera and record externally to a cheap HD ProRes422 HQ recorder. The down conversion is much cleaner this way and ProRes beats the pants off of the 200mbps recording mode which is still based off of a H264 encoder. $295.00 plus a cheap 7200 RPM drive ($70 for 1TB) is not a lot of money to achieve that level of quality.

While many would prefer to record 4k externally if they could the cost exponentially goes up to do so. You really need to ask yourself do you really need external 4k if you are delivering HD or 2k anyway? Most Hollywood films are edited and mastered at 2k and there is nothing at all wrong with shooting 4k for a 2k workflow. In fact that is a pretty standard norm in Hollywood.

In this case you are letting the HDMI port do the down conversion instead of doing it in post.
 
Thomas Smet said:
While many would prefer to record 4k externally if they could the cost exponentially goes up to do so. You really need to ask yourself do you really need external 4k if you are delivering HD or 2k anyway? Most Hollywood films are edited and mastered at 2k and there is nothing at all wrong with shooting 4k for a 2k workflow. In fact that is a pretty standard norm in Hollywood.

In this case you are letting the HDMI port do the down conversion instead of doing it in post.
Click to expand...

But if you record 4K externally, say for example you shoot in 4K 4:2:0 and then go to 4:2:2 1080p 10 bit, won't that give more colour information than simply shooting 4K and then exporting on the timeline to 2K? The image will still look great if you do that in the edit, but if you use an Atomos etc, won't the colour space improve because you're going to 10 bit?
 
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