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GH5 VlogL effective bit rate and viability of usage.


Ryan Constantino

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Hello, I recently purchased the GH5 vlogL upgrade from Adorama, and came across this negative review in the comments section of the product page:

 

 

 

....Although V-log provides more dynamic range, it causes so much noise that you have to crush the shadows in post resulting in a loss of dynamic range, so really there is no gain there. the only way to fix the noise is by overexposing your footage, but this just results in some very bad banding and macroblocking issues due to the highlight compression done in camera. These issues could've been resolved by matching V-log to the highlight and shadow values of the camera's color space which is 0-255 or 8-bit but instead, since Panasonic wanted the profile to match VariCam, they threw away highlight and shadow information resulting in only a 30-190 or 7.32-bit color space. So every time you shoot V-log you're only getting 7.32-bits instead of 8-bits and most likely lots of noise, macroblocking, and banding.....

 

I still have a lot to learn with regards to Log recording methods and am curious if what this reviewer is saying holds any truth? From my experiences with VlogL so far, it seems like it's stretching what the GH5 sensor can do. Anyone know more about this?

 

Adorama link: https://www.adorama.com/r/ipcvl-reviews

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Panasonic uses the same activation codes for the GH5 as for the GH4. The review you've quoted is true for the GH4, which could only record 8-bit internally, as well as for the 8-bit recording modes of the GH5.


If you choose a 10-bit recording format on the GH5, V-Log-L will use the range from 128-768 out of a possible 1024. So while it's still not the full 10-bit range, there are 640 possible code values in 10-bit V-Log-L compared to the 160 code values in 8-bit V-Log-L (or compared to the 256 total possible values in any 8-bit recording format). This is a significant improvement for color grading, and will reduce the types of artifacts that the review you quoted describes.

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I've used the GH5 on 10 bit 4:2:2 mode quite a bit and the microblocking is insane even on 1080p. I have no idea how anyone uses these cameras to create a decent image. Coming off a Blackmagic Pocket cinema camera which has zero microblocking ever, the GH5 seems like a toy codec wise. Everyone I know who gets a decent image from one, is using an external recorder.

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I've used the GH5 on 10 bit 4:2:2 mode quite a bit and the microblocking is insane even on 1080p. I have no idea how anyone uses these cameras to create a decent image. Coming off a Blackmagic Pocket cinema camera which has zero microblocking ever, the GH5 seems like a toy codec wise. Everyone I know who gets a decent image from one, is using an external recorder.

Is this mitigated with the GH5s? So if an external recorder is used, there is no problem or less of one? Considering this camera for micro budget doc. Might have to look elsewhere.

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