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Nick Hope

Panasonic LUMIX GH5 for underwater video

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I have to admit the new Atomos screens (in the Flame and Inferno units) are to die for underwater, ultra bright and sharp and using the RGB parade, I can manually adjust the WB using Kelvin instead of using slates while eyeing the Red channel.

 

Richard, you can do Kelvin tuning on the GH5 natively. Put on the RGB overlay on the DNC and you get the same tool - maybe not as effective as with the Atomos, but it works (see Kelvin in upper right corner with up and down arrow to adjust)

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I'm not a technical expert by any means but the way I understand it, is that any white balancing at depth, whether manual or automatic, will introduce a certain amount of noise, because effctively you are 'artificially' inreasing the red channel - and that will add more noise to that channel, because by white balancing you are not adding any more information to that channel. Things should be better in 10bit because of the addl. color info compared to 8bit, so I am having good hopes in the GH5 in that respect

Whether there is more noise introduced on a Panasonic compared to lets say Sony I dont know. But I can tell you from my time with the Sony AX100 camcorder it was introducing plenty of noise if you where below 15 meters on ambient light only. I guess thats just a critical depth fo most cameras where they start to struggle.

 

Right -- what you're essentially doing when you're white balancing at depth is telling the camera to apply gain to the brightness levels recorded by the "red" photoreceptors. So it's equivalent to boosting the ISO, and will make any existing noise in the red channel more apparent. With the GH4, the noise was quite visible/distracting when trying to white balance around 20 meters (especially if your base ISO was already 400 or 800 to account for the lower light).

 

This step happens before any of the data is encoded into an 8 bit or 10 bit video file-- white balance is processing applied to the 12 bit data coming right off the sensor. So the final recording format isn't going to make a difference to the amount of noise. The GH5 should still be better overall then the GH4 simply on account of newer sensor technology, using a larger area of the sensor for video and better noise reduction, but the differences are probably similar to the overall improvement in low light performance. DXOMark rates the GH4 and GH5 as essentially identical in terms of noise performance, so I wouldn't expect the GH5 to be significantly better than the GH4 in terms of noise when white balancing. A full frame camera like the 1DX Mark II should be 1-2 stops better, which is what the Backscatter guys seem to report as well.

 

As to whether a 10-bit 4:2:2 h.264 file will make it easier to correct a bad white balance in post than an 8-bit 4:2:0 file h.264, it might make a bit of a difference, but it won't be night and day like you would get if you were recording raw. During the encoding process that creates the h.264 file, the 12 bit data in the red channel is going to first get confounded with the signal from adjacent blue and green pixels as part of debayering. Then it's going to get compressed from a 12-bit space where 4096 gradations of brightness can be represented to a 10-bit space that only supports 1024 gradation. That alone throws away 75% of your data. Then you end up throwing away the color data for half the pixels when you go from 4:4:4 to 4:2:2 color. So you're already down to 12.5% of the original data (not accounting for errors introduced by debayering based on the wrong white balance) before you even get to the compression stage. Then you add the fact that h.264 compression tends to preferentially eliminate data in the shadows. Your red channel underwater is mostly going to contain data in the shadows if it's not pre-boosted by a "proper" white balance before this stage is reached.

 

So yeah. If you want to retain information in the red channel when shooting in a compressed video format, you need to make sure that the data is properly baked in by a good in-camera white balance. Since the red channel signal is going to be very weak coming right off the sensor, if you don't boost it significantly before recording it (and more importantly, compressing it substantially using h.264 compression), you'll end up trying to reconstruct what should be dozens of shades of red of various brightness from very little data indeed.

 

All of which is to say that, when recording to any sort of compressed RGB or YUV codec underwater using only ambient light, the camera's ability to do a proper white balance in the 40000-50000 kalvin range with significant magenta push is far more important to the final result than the bit depth or color depth of the recording codec. Good white balance flexibility will get you nice colors even in a 8-bit, 4:2:0, low bitrate codec. Case-in-point: canon dslrs. Whereas if your camera won't let you set a white balance higher than 9900 kalvins (e.g. all Sony mirrorless cameras that, and maybe some of their cinema cameras too), the codec won't matter. At least, not unless you can record the raw sensor data before debayering and compression.

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oooooh that is even better than the Atomos displays! WOW

 

One (serious) grain of salt: the GH5 only seems to be able to tune in Kelvin up to 9900 - which would not be of much use for underwater. How much can you tune in on your Atomos?

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Are you sure you looked at the DNC-7A back then? They have updated the DNC-7 to DNC-7A a while ago, but I dont think it was four years ago but I may be wrong - tiem goes bye fast... Easiest would be for you to ping Alex at diveandsee. I am sure he'll give you some more on his plans.

 

Burkhard

Might've been the DNC-7.. I think it was right around the time of the DNC-7A release though. So let's say 3 years ago :)

 

 

 

Richard, you can do Kelvin tuning on the GH5 natively. Put on the RGB overlay on the DNC and you get the same tool - maybe not as effective as with the Atomos, but it works (see Kelvin in upper right corner with up and down arrow to adjust)

 

Interesting! So in the manual adjustment mode, how high can you push the Kelvin temperature? Past 10000k? Does doing a custom white balance off a white slate let you boost the reds further than just entering the Kelvin temperature manually?

 

EDIT: Just saw your answer above. 9900k sounds like the same limitation as on the Sony's. But perhaps you can actually achieve a higher Kelvin temperature using a custom white balance off a slate at depth.

Edited by dreifish

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Richard, you can do Kelvin tuning on the GH5 natively. Put on the RGB overlay on the DNC and you get the same tool - maybe not as effective as with the Atomos, but it works (see Kelvin in upper right corner with up and down arrow to adjust)

 

Is the overlay at the bottom of the screen generated by the DNC monitor, or by the GH5 itself? Does the DNC have any options for displaying false color or zebras (for exposure)? How about peaking/punch-in and/or other focus aids?

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the overlay is generated by the DNC. You also have the option to overlay false color, vectorscopes, various zoom-ins etc. Peaking and Zebras as well, but I actually use both of those from the GH5 and have them displayed on the DNC as they work so well and I got used to them overland :)

 

Manual WB is supposed to work very well on the GH5 underwater. I am planning to use that primarily, just wanted to see whether that Kelvin tune-in Richard mentioned might be another option. I'll try it out in August when I get underwater anyway...

 

Burkhard

Edited by bubffm

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One (serious) grain of salt: the GH5 only seems to be able to tune in Kelvin up to 9900 - which would not be of much use for underwater. How much can you tune in on your Atomos?

 

Same on the GH4 - up to 9900k. There is no WB adjustment possible on the Atomos units, just eyeballing to make sure the RGB parade levels roughly.

 

Above 20m I'm using Magic Filter (and when they arrive, the Cyan LEDs for my Keldans) - so there is enough movement within the confines of the Kelvin scale to get a good WB, and below that setting it to 5400k, to match my CRI LEDs

 

Manual WB is supposed to work very well on the GH5 underwater. I am planning to use that primarily, just wanted to see whether that Kelvin tune-in Richard mentioned might be another option. I'll try it out in August when I get underwater anyway...

 

I just find using the up/down buttons and looking at the scopes a lot easer than using something to WB off.

 

Have they fixed that with the GH5, where if set to 10bit 4:2:2 and you have HDMI connected, you can now manually set white balance.

 

On the GH4, outputting 10bit to the HDMI, disabled the options to '[sET]' to manual WB, all you can do is use the standard options or adjust it via Kelvin

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Have they fixed that with the GH5, where if set to 10bit 4:2:2 and you have HDMI connected, you can now manually set white balance.

 

On the GH4, outputting 10bit to the HDMI, disabled the options to '[sET]' to manual WB, all you can do is use the standard options or adjust it via Kelvin

 

Yep, that all works with 10bit 4:2:2 and external monitor connected.

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(...)

 

Above 20m I'm using Magic Filter (and when they arrive, the Cyan LEDs for my Keldans) - so there is enough movement within the confines of the Kelvin scale to get a good WB, and below that setting it to 5400k, to match my CRI LEDs

 

(...)

 

 

In your below-20 dives, with magic filters on, how does MWB behave in shallow waters (begining or ending the dive) ?
I guess you have the filter fixed on the lense

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In your below-20 dives, with magic filters on, how does MWB behave in shallow waters (begining or ending the dive) ?

I guess you have the filter fixed on the lense

I remove the filters if my intended dive site is below 20m and use normal lights and get closer.

 

Which are mounted internally. So it's fixed decision before the dive.

 

My GH5 will be with me on Weds, (couldn't refuse at the moment with the Euro being strong against the £ and Panasonic UK doing a £100 trade in offer. I got the body for 1495€ delivered ) alas with that and the CYAN Leds. I'm spent. So the NA-GH5 will have to wait a couple of months.

 

 

Regards - Richard

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I just got back from Dominica shooting the GH5. I fixed the focus problem with custom settings. I will post some video later and what setting I used

 

Sent from my SAMSUNG-SM-G935A using Tapatalk

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(...)

 

My GH5 will be with me on Weds, (couldn't refuse at the moment with the Euro being strong against the £ and Panasonic UK doing a £100 trade in offer. I got the body for 1495€ delivered ) alas with that and the CYAN Leds. I'm spent. So the NA-GH5 will have to wait a couple of months.

 

(...)

What a nice price!!. Can you share with us where you bought it?

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What a nice price!!. Can you share with us where you bought it?

 

I ordered it from CVP.com - http://cvp.com/index.php?t=product/panasonic_gh5_body

 

Base price before tax is £1415.83, take off another £83.33 for the trade in (body only), another £10 with their '10off' coupon on first orders and it was around £15 delivery to Gibraltar, add to that on the day the euro was at 1.115 to £1.

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Just lend me your NA-GH5 and I will test WB at 100m :mocking:

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Lucky if you live near tax-heavens like Gibraltar....

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This is price for the different options of DNC-5A:

DNC-5A(H1) - $2500 HDMI input only
DNC-5A(H2) - $2700 HDMI input, HDMI output
DNC-5A(HS) - $2700 HDMI input, SDI output
DNC-5A(S1) - $2500 SDI input only
DNC-5A(S2) - $2700 SDI input, SDI output
DNC-5A(SH) - $2700 SDI input, HDMI output

http://www.diveandsee.com/products/underwater-monitors/dnc-5a

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Game over

 

 

Professional 400Mbit ALL-I intraframe codec for 10bit 4K 4:2:2

Open Gate High Resolution Anamorphic Mode (4992 x 3744)

Hybrid Log Gamma with view assist feature for HDR shooting

New and improved autofocus engine for video

Performance optimisations and bug fixes

 

http://www.eoshd.com/2017/08/panasonic-gh5-review-and-exclusive-first-look-at-version-2-0-firmware/

http://www.panasonic.com/global/consumer/lumix/gh5_firmware.html

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Apart from the 60fps 422 10bit, makes external recorders like my Inferno, completely redundant.

 

Good play Panasonic, impressed.

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I have big hopes for the AF upgrade. Particularly with bad visibility / many particles underwater focusing the GH5 is a real challenge, and I don't not have focus gear for some lenses to focus manually...

 

The all-Intra truly sounds amazing. I am also thinking about playing with anamorphic overland.

Edited by bubffm

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I'm reading on other forums people writing that 400mb intra codec is just a gimmick actually useless and othet ranting.

Obviously people have different needs and perfect video camera doesn't exist but the fact remains that at that price point you get the best market features/price ratio.

 

Probably it was the same for previous GH models but they struggled a lot breaking market lock-in.

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particularly with bad visibility / many particles underwater focusing the GH5 is a real challenge, and I don't not have focus gear for some lenses to focus manually...

Do you mean with macro?

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