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Panasonic GH5: what do you use to get the correct exposure?

GH5 exposure

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#1 Interceptor121

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Posted 14 June 2018 - 02:02 PM

I have been playing for a few days with the GH5 and I have noticed that in addition to the obvious metering, histograms and zebra pattern the camera has a live waveform monitor.

 

Does anyone use it? Do people with external recorders or monitors use it?

 

I am using HLG to shoot HDR but this applies equally to log or standard shooting


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#2 Pajjpen

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Posted 14 June 2018 - 02:12 PM

I have an external monitor to go with my gh4 as of now but I guess this applies to me as well, but honestly I haven't even looked for waveforms as I quite like the zebra :)

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#3 bubffm

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Posted 14 June 2018 - 11:36 PM

Its of course nice to have that waveform available internally on the GH5. But it restricts / overlays the viewable area, so I never use it. If I monitor on the camera screen, then Zebras. But preferably I use my external monitor, where the waveforms can be tuned to appear below the picture frame so dont overlay anything.

#4 thetrickster

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Posted 14 June 2018 - 11:56 PM

Filming underwater, I find trying to use a fully manual mode is hard, the changing conditions, lighting etc lends itself to using one of the semi auto modes. I use Multi meter mode also, as it doesn't cause big shifts in exposure if using one of the auto modes.

 

With the GH5 and GH5s where AutoISO works with fixed apertures and shutter speeds  (and the ISO performance is a non-issue) the need to 'monitor' exposure to me is a bit of a non-issue, with the GH4 i tried full manual and trying to adjust, but failed most of the time.

 

I only tool I find useful is the RGB parade, if doing a MWB on my monitor. But the GH5 screen I try and leave as bare as poss.


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#5 Interceptor121

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Posted 16 June 2018 - 02:52 AM

So is it fair to say that nobody shoots with manual exposure?
I find manual very tricky unless you are in control of light for example during close up work


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#6 Lionfi2s

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Posted 16 June 2018 - 05:42 AM

So is it fair to say that nobody shoots with manual exposure?
I find manual very tricky unless you are in control of light for example during close up work


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I shoot manual only



#7 Interceptor121

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Posted 16 June 2018 - 05:45 AM

I find manual problematic near the surface because base iso 200 or 400 is too low combined with shutter 1/50 with end up with small apertures easily
On a close up no problem
I wonder what does the camera do in creative mode P? Does it follow some shutter angle rule or not??


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#8 bubffm

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Posted 16 June 2018 - 06:28 AM

So is it fair to say that nobody shoots with manual exposure?
I find manual very tricky unless you are in control of light for example during close up work
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Like Richard, I am mostly fixing my shutter and my desired aperture and let Auto-ISO do the correct exposure. Works most of the time and with the GH5s theres now even more leverage. But for example shooting upwards into the sun, this method results in underexposed footage, ie you need to manage manually. Also out of caves / holes into the light is not turning out correctly.

Only slight drawback is that you dont actually see which ISO the cam is using at any given point in time. But you can set your ISO Limit to avoid overly noisy images.

But most of the time, Auto-ISO gives quite satisfactory results imho.

Edited by bubffm, 16 June 2018 - 10:46 AM.


#9 dreifish

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Posted 17 June 2018 - 02:31 AM

I shoot in manual unless I know I need to follow fast action where the subject might be below me one second and above me the next (exposure can vary quite a bit when shooting down vs up in the water column). Like others, I usually lock down my aperture and shutter speed and then adjust exposure using ISO only, or go into AutoISO where necessary.

 

I like knowing what my ISO is at though, which is why I shoot in manual. It lets me know the conditions in which my lights are going to perform well and when they're going to be too weak to bring back colors. And with the excellent layout of controls on the Nauticam GH5 housing, it's quite easy to adjust the ISO on the fly manually. 

 

In terms of monitoring, I primarily rely on zebras to tell me what's blowing out and the camera meter -- I find that -2/3 to -2 stops underexposed for ambient light (according to the internal light meter) usually produces the most pleasing "blue" water column color for me. So that's what I aim for.

 

For those of you who do use the waveform, what IRE do you aim to expose the background water column at, generally? I'm quite curious what IRE level of blue people find most pleasing as a backdrop.

 

And by the same token, what do you set your exposure by? Topside, I usually expose to get the skintones of people in the right IRE range, and let the rest of the image fall where it may. Since underwater people shots are a lot less common, I'm curious what everyone sets their exposure by? 18% grey? The water column? Expose to the right just shy of blowing the highlights and fix it later in post? 



#10 Interceptor121

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Posted 17 June 2018 - 07:40 AM

The idea of locking aperture seems appropriate if you shoot with a dome port. For example on the 7-14mm I would not go below f/5.6 however with a wet lens on a flat port do you really need to do that? Are you not better off working in S mode with fixed shutter speed and let the camera work things out.

 

If your camera is not moving like a close up or a fixed position wide angle shot then I can agree that manual is fine and there are no real issues like taking a still image net of movement in the frame

 

The IRE question on water column is interesting. I guess for shots with light the water colour will be pretty much dictated by your main subject and the shutter rule. So if you shoot at 24/25p your shutter will be 1/50 and you will get a lighter blue than if you shot double frame rate 1/100 or 1/125

 

For ambient light I do not know really if this concept holds as you set IRE on your subject as you say you do on land and then try to avoid clipping. Generally IRE for broadcast are 10-90% for safety so you need to be careful to underexpose too much or shadows would be gone, this is where filters come helpful as they act only on certain wave not all of it. A filter takes away one stop from the image in general but only from the blue so your water column becomes more pleasing and generates more perceived contrast. White balance a grey card or similar does not have the same effect of a filter and you get an image that has less saturation and less contrast so if the blue is a bit washed out it stays so afterwards. Filters tend to introduce hues so when combined with white balance it works best. This is however a long debate filter no filter and not generally connected with getting the right exposure!


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#11 Davide DB

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Posted 23 June 2018 - 01:07 AM

I can't afford the GH5.
I shot with GH2 GH3 and now GH4.

Always worked full manual.

No problem at all. In many years I missed very few shots.

I used histogram on GH2 and GH3. Zebra on GH4
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#12 Etc

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Posted 05 September 2018 - 12:37 PM

I'm reading here about working on S mode?. Are we talking about Gh4/5 or just the GH5???. The GH4 on Automatic aperture will change in abrupt steps.. useless!!! 



#13 Interceptor121

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Posted 05 September 2018 - 01:16 PM

I'm reading here about working on S mode?. Are we talking about Gh4/5 or just the GH5???. The GH4 on Automatic aperture will change in abrupt steps.. useless!!! 


Generally a camera has an algorithm when light changes
If you fix one variable say shutter speed it will change aperture first and iso after when going in less light iso first and aperture after in bright light
If you fix two settings it will eventually max out which in low light means black image in bright light clipping
Considering you dont zoom underwater when you move slowly the adjustment is quite subtle. Some people fix aperture on dome to avoid depth of field changes and blurred corners but then when you are in bright light unless you are still and the light doesn’t change which happens only with macro shots you may end up clipping...


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