Panasonic GH2 10 Bar housing test

[matdiver]

Hi,
I finally got around to doing some testing of my GH2/10 Bar housing. Manual white balance using ambient light was disappointing.... but with very basic quick grading in Vegas the colours seem to be pretty good. PZ 14-42 behind flat port and red filter was plenty wide enough for me. I generally just do fish and reefs, not large wrecks. Apart from MWB, image quality was great. 50p is fun!
This is just a test video, nothing artistic:




[video=vimeo;60125847]https://vimeo.com/60125847[/video]

Cheers,
Matthew

 

[ScubaBob92651]

Watching most of the video I was surprised that you weren't able to get better results with MWB - then I saw the Slo-mo footage and the white balance was spot on - what did you do different (was this using video lights or was it ambient light)? I find I've been able get great results using MWB and ambient light - in fact I have yet to grade a single clip of footage. Using my 7-14mm I have been using a red filter between the lens and camera. Though, I have recently started using the 12-50mm oly lens and find I can MWB without a filter, at least down to 45fsw so far..

 

[Interceptor121]

Uhm
I would try a few things, firstly don't use the filter at all and just white balance eventually you can add some tint to it
I also notice quite a fair bit of pincushion distortion at the edges. That may be the flat port effect. The camera is very sharp in the center and the corners are squashed not soft
Have you thought about a dome?

 

[matdiver]

ScubaBob,
thanks very much for the info. I really enjoyed watching your GH2 test (again!) and now I'm thinking that I must be doing something stupidly wrong. Around 4'24" in your video for example, the colours are just perfect.

Please please tell me what you are using as your WB reference - white slate, hand, surface of the water? Whenever I tried to use the water surface I got the message "unable to proceed - scene is too bright". My picture settings were "nature" and everything set to "0", but next time I will try experimenting with vibrant and boosting the saturation in camera. In the exposure settings I think I also need to use aperture rather than manual, so that I can access auto ISO when I need to. If you're filming something impressive like a manta which comes up from below, then wheels up to the surface, the shot would be ruined with fixed ISO.

I've checked the slo-mo part of the video, and this was at a coral head right towards the end of a 90 min. dive, so it would have been after 9 am when the sun was well and truly up, and at about 5m. No grading, just slightly increased the contrast and darkened. There are no lights used on any part of my video, it's all ambient.


Matthew.

---------- Post added February 21st, 2013 at 09:06 AM ----------

Interceptor,
actually the bit with the pin-cushion distortion was when I was experimenting with a dome!!! The results turned out to be unsatisfactory also because the lens flare was pretty bad, particularly at shallow depths. A friend who's been using domes for years has explained that a wide open aperture and the high number of lens elements involved with a 14-42 zoom+ 0.7 x WA converter screwed onto it is not the optimal way of going about things...
WB without a filter - well, I'm desperate enough to try anything! WB of the palm of my hand doesn't make much sense to me, because blotchy whitish-pinkish is so different from my trusty white dive slate. However, I remeber reading on one of the forums about a guy with an HD cam who had discovered that white fins with thick red lines drawn on in marker pen worked best for him.

Matthew

 

[Interceptor121]

Yes this is not exactly like a camcorder, it must have something to do with how the lenses are built. But the pincushion I think is all over the video
I white balance on a white slate and with few exceptions I never correct in post processing.
Maybe start getting the colour right as that is just the camera functionality and on the optics you need to do some more work I guess. Is it possible to put a wet lens outside the housing??

 

[ScubaBob92651]

ScubaBob,
thanks very much for the info. I really enjoyed watching your GH2 test (again!) and now I'm thinking that I must be doing something stupidly wrong. Around 4'24" in your video for example, the colours are just perfect.

Please please tell me what you are using as your WB reference - white slate, hand, surface of the water? Whenever I tried to use the water surface I got the message "unable to proceed - scene is too bright". My picture settings were "nature" and everything set to "0", but next time I will try experimenting with vibrant and boosting the saturation in camera. In the exposure settings I think I also need to use aperture rather than manual, so that I can access auto ISO when I need to. If you're filming something impressive like a manta which comes up from below, then wheels up to the surface, the shot would be ruined with fixed ISO.

I've checked the slo-mo part of the video, and this was at a coral head right towards the end of a 90 min. dive, so it would have been after 9 am when the sun was well and truly up, and at about 5m. No grading, just slightly increased the contrast and darkened. There are no lights used on any part of my video, it's all ambient.

Matthew

I generally white balance as close as possible to the scene, which most often is the sand near where my subject is. The WB slate is a waste of time IMO, unless your subject is going to be exactly the same distance away as the slate you used to MWB. Sometimes it may take me 2-3 attempts to get the right color if the terrain doesn't contain enough contrast. With the GH2, it's nice being able to save a couple of MWB presets throughout the dive as I get deeper or ambient light changes. This is also helpful when switching from close-up using lights back to ambient light, or for mid-water shots where you don't have the time or target to get the MWB. I've left the camera mostly in the default picture settings. Those "cinematic" peeps can talk for ever about capturing footage that can be easily graded in post - but in a non-RAW workflow when it comes to underwater video, it's best to get the correct white balance with your captured footage.

I also always shoot in full manual. I find it easy to change the ISO fairly quickly if needed, or change the f-stop if I have the latitude given the available light and desired DoF.

 

[Interceptor121]

I like the slate as you always have it with you, when you dive on walls you may not have a sandy bit for a long time
I agree on the no need for post-processing for what concerns the manual mode it depends on the camera, in video the shutter priority is pretty much fixed so if you set also the ISO effectively you set aperture too. Generally I think the manual mode is overrated except in macro

 

[matdiver]

Thanks again, to both of you. I clearly have some more testing to do, and a pretty ugly video to delete from my Vimeo page!
Matthew

 

[Interceptor121]

I would recommend you practice white balancing on land with a slate as obviously something is going wrong. I had a Sony RX100 and it would not balance correctly if the exposure was more than 2 Ev off, maybe your camera has the same behaviour

 

[matdiver]

Hmmm, actually maybe you're on to something with the relationship between WB and exposure. I tried the white slate with auto ISO in the 33m pool we have here in Belgium, and the results were very good. WB on land was always no problem, but as I'm new to ISO and shutter control underwater I think that was where I was making a mess of things. I'm really a newbie with this setup. Unfortunately it's going to be quite a few months before I get back into the sea :-(