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Member Since 25 Oct 2013
Offline Last Active Apr 11 2018 06:49 AM

#394320 Who is excited about Blackmagic Pocket Cinema 4K?

Posted by dreifish on 11 April 2018 - 06:51 AM

It really is a bit of an odd form factor, isn't it?


I can't see this as being all that useful hand-held since the monitor doesn't swivel out or even tilt -- and without an evf, can't really use it like a DSLR. Given how wide it is, it's not going to work great on any of the one-handed gimbals. Seems like this is meant to live on a tripod..




Its gonna be a big housing! (But obviously you potentially don't need an external monitor...)



#394110 GH5S Better colour

Posted by dreifish on 05 April 2018 - 08:32 AM

Yeah, the vectorscope comparison is pretty interesting. Having less of a green tint could definitely benefit underwater footage, but the differences aren't astronomical -- I imagine you could tweak the GH5 to be pretty similar to the GH5s just using the G-M and A-B WB adjustments..

#393895 IS IT WORTH IT? GH5s - No Stabilization

Posted by dreifish on 29 March 2018 - 09:16 PM

Yeah. In general, you want to get the things that allow you to shoot what you couldn't otherwise film first, and things that don't really give you any new capabilities (but do allow you to do what you were doing before easier) second. 


I think the monitor is a lot more essential for macro than for wide-angle shots. And the lights vice-versa. So decide what you're more interested in filming first. For the type of high-magnification macro that would benefit them most from a monitor, you'll also what a tripod of some sort. 

#393412 IS IT WORTH IT? GH5s - No Stabilization

Posted by dreifish on 15 March 2018 - 08:18 PM

Yes, I've done a few tests with HLG. -- for some reason, if I bring the footage into a regular (non HDR) timeline in FCPX, the colors are all wrong and there's no easy way to normalize them

Have you tried HLG? Can't remember where I read it but someone was actually advising to bump up the in-camera saturation and take saturation off in post if needed.


Yes, I've done a few tests with HLG. With underwater shots, for some reason, if I bring the footage into a regular (not wide color gamut) timeline in FCPX, the colors are all quite a bit off and there's no easy way to normalize them. So I prefer using VLOG over HLG for that reason -- at least with vlog there's an easy official LUT to covert it to REC709 that will get you in the ballpark for color correction. But as I mentioned, 99% of the time I think you're just fine shooting in standard without any sort of log profile at all.


Regarding saturation, theoretically I think you'd indeed be better off removing saturation in post rather than adding it in terms of preserving as much color shade separation as possible. But the best option IMO on cameras that don't record in raw is to get the saturation in camera as close to the final output you want so you don't have to do any tweaking in post. That's why I prefer the standard color profile over CineD or Vivid/Landscape. CineD I find desaturates the footage in a way that looks unnatural for underwater shots and it's hard to get them to look good by just adding saturation in post. Conversely, Vivid/Landscape are a bit too saturated. If you reduce the saturation in post, you get a result that looks ok, but not any better than the standard picture profile IMO.

#393410 A7III is here !!!

Posted by dreifish on 15 March 2018 - 08:06 PM

To be honest, I don't see anything in the Sony A7 line that would recommend it for underwater video over a GH5, and the A7III doesn't change that. Great land camera, and I may end up picking one up for that reason, but underwater? Why?


Full frame is actually a liability underwater as far as I'm concerned -- it means having to shoot at higher apertures to get reasonably sharp corners, which negates any low light advantage full frame might have. Just take a look at the samples I and TaxiDiver posted above -- even at web resolutions, the corners of his shots are visibly soft, whereas I was shooting at F4 and getting perfectly sharp corners. (I've used the WWL-1 + Panasonic 15mmF1.7 lens combination as wide as F2 with good corner resolution). 


You also cannot set an accurate white balance without filters. Even with filters, the results will need tweaking in post to look good, and even then you can only take it so far. I suppose color is a matter of taste, but I wouldn't call TaxiDiver's samples particularly pleasing.


I've used an A7RII underwater for two years. Can you get good results with it? Yes, especially with lights. Would I go back after switching to the GH5? No way. There's not a single thing I miss about it as far as underwater video is concerned. It's definitely a better stills camera than the GH5 with the right lenses, and the shallow depth of field is nice when filming 'cinematic' people shots on land. But if your main focus is video, at this price point, I think the GH5/GH5s is a much more capable camera.  I'd only trade it for a Canon 1DXII (maybe -- the video files are very large because of the inefficient codec), Canon C200, or a RED.

#393122 IS IT WORTH IT? GH5s - No Stabilization

Posted by dreifish on 09 March 2018 - 03:00 AM

Screen Shot 2018-03-09 at 7.43.55 PM.jpg  Screen Shot 2018-03-09 at 7.44.15 PM.jpg  Screen Shot 2018-03-09 at 7.44.24 PM.jpg



Yes. There's quite a bit of extra contrast added. Adding additional saturation after the LUT only produces less natural-looking colors. My point isn't that the color-corrected result from v-log looks terrible -- it just doesn't look as good (and certainly not any better) than the color corrected result from shooting in the standard picture profile in 8bit.


Basically, when you choose to shoot a desaturated image initially, what you're doing by compressing the saturation range (as all log formats do) is throwing away the subtle differences between shades of color. Adding saturation back in post doesn't bring back those subtle differences -- they're gone forever. Shooting in 10 bit does alleviate this to some extent, but at the end of the day, you're not gaining anything. Probably better to just shoot in 10-bit using the standard picture profile. 

#393117 A7III is here !!!

Posted by dreifish on 09 March 2018 - 02:20 AM

Samples at 10/15m, CMWB TaxDiver? 


From the GH5, 10m, MWB, no filters, ambient light only. (before/after correction):


Day 3 - Boo & Fiabacet 3.jpg Day 3 - Boo & Fiabacet 2.jpg




I agree that below 15m you need torches though. No amount of white balancing ambient light is going to help you.



#393114 IS IT WORTH IT? GH5s - No Stabilization

Posted by dreifish on 09 March 2018 - 02:11 AM

 GH5, CWB with ambient light at 10m, no red filter, standard picture profile, 4k60fps in 8-bit 4:2:0 at 150mbs.


Before/after simple color correction in FCPX (WB->warmer/+magenta; crushed shadows)


Day 3 - Boo & Fiabacet 3.jpg

Day 3 - Boo & Fiabacet 2.jpg



For the record, I tried shooting same scene at 4k24fps in 10-bit 4:2:2 400mbs with v-log and was much less pleased with the results after applying the official lut and trying to color correct the scene. I think you give up too much color information when shooting in v-log. 


Day 3 - Boo & Fiabacet 5.jpg

#392971 IS IT WORTH IT? GH5s - No Stabilization

Posted by dreifish on 03 March 2018 - 08:45 PM



Yes I shoot ambient light in Socorro with Magic Filter. I know it's deep so I need to use custom white balance method to bring out the blue color. Unfortunately the visibility got bad half way into the trip so the white balance was challenging. At 3:30 into the video, you see some light on the Manta, it's a Keldan light from the boat's videographer, he swam around and shine his light everywhere and piss many people off, so watch out for people who abuse high power video light. Since I shoot ambient light, it's hard to swim on top of the Manta to capture the top side view of the manta because everything will be very dark. So it's a tricky experience for me.


As for your question of Canon 5DM4, I know 2 very skill videographers who are highly disappointed with it and decided to move to the 1DX M2 since the price is still manageable for them. Besides the file size, the big drawback of the 5DM4 is its crop factor, it's so bad that you can't really shoot good Wide Angle with it. I'm not sure if they corrected the crop factor through firmware update. Also, the 1DX M2 can shoot 4K 60 fps, so it's a highly desire feature with many professional videographers.


The crop factor on the 5D4 might actually be an advantage for underwater work, assuming you can use third party APSC lenses. Generally, for underwater work you want as great a depth of fields as you can get, so smaller sensors are actually a good thing. One of the reasons I think m4/3 is great for underwater video. 


Touching a bit on high powered video lights -- I've yet to see a single example of what I'd consider rich underwater colors that relies solely on ambient light, below 10 meters. You can't really beat physics unfortunately.. Red light don't penetrate very deep in the water column, and no amount of custom white balancing or red filters is going to bring them back if they're just not there.

#392970 GH5 Settings

Posted by dreifish on 03 March 2018 - 07:56 PM

1. I shoot 4k60p in 150mbs LongGOP 90% of the time. Gives you great flexibility to play it back at normal speed or 2.5x slowmotion in a 24fps timeline. Can also zoom in in post if delivering to 1080p. Standard picture profile, 1/125 shutter (or 180/179 degree shutter -- the latter supposedly produces better continuous autofocus results, but I rarely use CAF -- just not sufficiently reliable or necessary, imo). 


2. I've tried white balancing off a custom 18% grey card  and off my palm. The latter gives much more pleasing results IMO. For whatever reason, CWB off the grey card produces very greenish results.


3.  I set a CWB off my palm for 2.5m, 5m, 7.5m and 10m depth and store it in the 4 memory banks. Then I simply switch between those stored white balance settings. Gets you in the ballpark. Below 10m, I either use the 10m CWB or switch to video lights (and either fixed WB at 5200k, the color temperature of my lights or the 2.5m CWB if the subject is a bit further away from the camera.) 

#392969 A7III is here !!!

Posted by dreifish on 03 March 2018 - 07:47 PM

Nothing I've seen suggests that the A7III/A7RIII/A9 have fixed Sony's inability to set a custom white balance properly underwater (with or without a filter).


If you think Sony's ambient white balance underwater is just fine, I suggest you try comparing it with Canon or newer Panasonic camera -- it's quite a difference. 

#391051 IS IT WORTH IT? GH5s - No Stabilization

Posted by dreifish on 09 January 2018 - 06:48 AM

Noise has basically never been an issue for me shooting the GH5 underwater. You can usually open up to F5.6, so ISO never really goes over 1600. So.. for underwater use, I see no advantage to the GH5s over the GH5. The lack of in-body image stabilization is a big negative, on the other hand.

#390118 Sony White Balance for UW?

Posted by dreifish on 06 December 2017 - 11:25 PM

Thank you dreifish, that's very helpful. I don't anticipate shooting much video in shallow water. I'll be diving at the Marietas Islands, and from what I gather a typical boat dive there is between 40-70 feet. I know the 2000 lumen Hydra is not a lot of light to work with, but the Sony a6300 seems to be capable of shooting decent video at ISO 3200 or even ISO 6400. So I wasn't too worried about being under-gunned with the light, but I could be way off on that. I'll probably shoot video at 1/60th sec with an aperture of f/5.6, maybe f/4.0. I'm just hoping to get nice color on things like morays, or other fish or coral from a few feet away. Do you think I'd need more lumens at a depth of, let's say 60 feet?

Also, I am concerned about backscatter from this video light. I'll have the Hydra light mounted on a 4 inch flexi arm attached to the cold shoe. I was told at the LDS where I bought the light that that setup shouldn't cause much backscatter for video, but what do you folks think?

Thanks again for all the help!!


The issue isn't the sensitivity of the camera -- it's the ratio between the strength of your video light and the strength of the ambient light. If the ambient light is very strong (say, at midday, or in shallow water), then you have to expose for that -- you shoot at ISO 100, because ISO 3200 or 6400 would just end up with everything being blown out. The problem is that your light is nowhere near as powerful as the sun in these conditions, so even if you have it turned on, it's not going to restore much color. The cool ambient light is going to make up the majority of your exposure.


The reverse is true at night when there is no sunlight to outcompete, or just after sunrise/just before sunset, or the deeper you go. Then, you can expose for the strength of your light, and the weak ambient light won't blow everything out.


Backscatter is a function of how many particles there are in the water and the angle of your beam. This article is a good starting point to understand what causes backscatter and how to best position your lights to minimize it (note, you'll never be able to eliminate it. If there's particles in the same focal plane as your subject, they will be lit up by your light--or the sun, for that matter)

#390099 Underwater Videography Book Recommendations

Posted by dreifish on 06 December 2017 - 01:08 AM

I'm happy to organize workshops or one-on-one training in Indonesia.  A lot depends on what your goals are -- are you looking to make nice films of your holidays to share with friends and family? Looking to do professional work?


As for pros giving away their secrets -- I think the truth of the matter is there's relatively few secrets, and not a whole lot of people doing underwater video professionally. The ones who do tend to get work primarily based on their contacts and past history of producing results, not any particular secret technique they have :)

#390098 Keldan 8x - flux or CRI?

Posted by dreifish on 06 December 2017 - 12:11 AM


Yes, I have this setup. It is great for a mixed environment where you are shooting ambient and then move to an area (or the animal gets closer) where you want lights. You don't need to change white balance. I love that you sometimes can't even tell there are lights being used....like on schooling fish! 


There are negatives as outlined by previous posters.



... there's a reason you can't even tell that the lights are being used -- because they're essentially outputting so little light after the addition of the filters that it barely makes a difference whether you have the lights on or not except in extreme situations where the foreground subject is practically touching your dome and you need to fill in those shadows. 


They're nice for that use case, but that's about it. Don't expect them to matter in the majority of your shooting.


As for the red filter on the lens, basically what this does is the equivalent of setting a much higher (warmer) white balance in camera. So it can be helpful if your camera otherwise can't push a very warm white balance for video (Sony is the worst offender here), but completely unnecessary if your camera can (e.g. Canon DSLRs). But consider this -- those really high white balance settings tend to be needed at significant depth, where your ambient light video isn't going to look great (or natural) anyway, because you're trying to bring back colors that simply aren't there anymore.