The Gentleman's Underwater Bubble Blower Thread

[Ross Isaacs]

Please add me to list.....I too have not experienced the colour problem with the Epic X experienced by some here......When I had my HDCAM I had a URPRO filter cut to fit into the camera internal filter wheel which seemed to produce pleasing results for natural light shots deeper than around 10 meters. If I am lighting the foreground this filter either made the foreground to hot or if I white balanced for the lit area would turn the background very blue as you would expect.

 

[Greg F]

All those wanting to be added please send me email address you wish to use privately.

I guess I should have said that out loud LOL

 

[Tom Hamilton]

Greg, Hugh is pretty big in all of this. Please add him to the list, the BBC needs to be informed.

 

[Greg F]

No problem Tom, I just need to have him send me a email address he wants to use. I figure its better to send privately as having them public may not be best for science and all that. Science being botnet scans

 

[Johnny Friday]

I believe Hugh is on to something here....i believe it was Peter Scoons that was one of the first to replace the IR filter with a clear filter on his F900....with far superior results.

 

[Greg F]

Since its so quiet :emote_happyhappy:

I present you with some cowfish sex, I shot this about a week ago.

 

[Dave Blackham]

I believe Hugh is on to something here....i believe it was Peter Schoons that was one of the first to replace the IR filter with a clear filter on his F900....with far superior results.

I think this is similar to what I was trying to describe when we replaced the IR filters on one of our 3D rigs (not Epic cameras) which had a prism with in the optical chain. In our own case the IR filter on camera is red reflective as I think is epic and the prism reflected back down the optical chain causing magenta/red reflections and flares. We replaced the IR filter with an absorptive filter which appeared to the eye to be clear which fixed the issue. The IR filtration wasnt so good but the lack of reflections was much improved.

I wonder if the IR filter isn't being reflected back down the lens and seen by inner face of the port as some sort of magenta/red flare. Some ports have good AR some don't have any AR at all, the issue may also be affected by any rings, mounts or issues with in the lens as well if theres any reflective parts with in the lens being used. When the housing is underwater the port may be have differently when water is on one side of it so an in air test may not reveal the issue.

A related example of this was when the the new sensor surround or flock block was released and has helped enormously for our standard topside work by removing red flares from the sensor well.

Im just offering this as some random thoughts to consider to try to run the problem to ground.

 

[Frazier Nivens]

Back on the air, in REDUSER UW BB forum

Back on the air, in REDUSER UW BB forum

Back on REDUSER now that things are peaceful. Saw some of the posts, read through the pages and would be happy to also submit some files from Florida Keys shallow water and Bahamas, Blue water dives, Shallow white sand at Tiger Beach.

I do have some examples of the magenta hue when filming up at the surface, but that seems to be when I have a good white balance shooting horizontally and then aim with the same WB up toward the surface. And I've got some shots where the sharks swam up into the sun and the sun created a magenta hue, but I've found that by bumping the DRX up to 800 it took the magenta out.

Would be nice to be able to Key frame with a curve in RED CineX easily. Any plans for this?

Please also add me to your list and I'm happy to help in any way improve things now that things are peaceful.

I do think I"m getting pretty good color by creating looks and then importing those looks into camera, I have a Tiger Beach look created in RED CineX that I always use and it also makes thing nice in the touchscreen monitor. I do sometimes depending upon the lighting have a cyan cast to the shadow areas of the sharks that I can't seem to get rid of at times, even when properly white balanced.

I do also seem to get good color especially in shallow waters up to 50 ft. or so with my EPIC, very pleased with the camera UW for most things. Even my 3 CCD Sony HD camera seems to have trouble on the deep wrecks and will only WB up to 65-70 ft. The Tonic shots were done in Nassau with Terri Harrison and I think the colors are quite accurate, again another look created from a previous dive and shoot there. All these photos are very low res files.

The Blue Marlin was shot in beautiful blue water , Cat Island, Bahamas last month, and I didn't notice any issues with magenta when pointing the camera up at the surface. Just a beautiful blue. Oceanic Whitetip bite shot, I thought the colors were quite good. Again in shallow waters with good light. These were all shot at 96 fps.

Doing some new imaging at the Spiegel Grove shipwreck this week with EPIC and with the Canon 8-15mm lens, set to 12.5mm and 5k, will post some samples of what I get and compare them to the Sony HD camera from past filming on the wreck. Will see what the camera will do at 100 ft. on the wreck without and with lights. I think that I'll be able to get a decent WB at 60 ft. and then use setting the footage in RED CineX from REDCOLOR AND GAMMA 3 back to the original RED One REDCOLOR and GAMMA, I find this to help the UW footage greatly that I shoot, try it once on your UW footage and see if you like it. Then I tweak the grade further. Try this on some of your problem clips and see if it helps any. Rudi and Tom have been here in my edit suite in Keys and I've shown them some of the footage and I'm ok with the color I'm getting here for most part, I think they'd agree some of the shots were quite colorful and saturated with good contrast. Hope this may help some Respectfully for your consideration, my opinion and offered to help...if you like it use it.

Best to all,
Frazier Nivens, Ocean Imaging.

 

[Dave Blackham]

Is there any value in exchanging notes of what lens and what port exhibits the issue ? or is it likely to be more fundamental than that.

 

[Graeme Nattress]

I think we're looking at something more fundamental than lens choice. What do you mean by "port"? (and please excuse me - I'm new to the underwater side of things)

Graeme

 

[Michael Hastings]

I think we're looking at something more fundamental than lens choice. What do you mean by "port"? (and please excuse me - I'm new to the underwater side of things)

Graeme

The "port" is the waterproof glass or plastic that the lens sees through.

 

[Graeme Nattress]

Ok, "port" could be a factor - it's worth having a think on. Is clear glass always used or do the ports have different optical qualities?

Graeme

 

[Mark van Coller]

Some of them have anti-reflective coatings on the inside and a few have coatings similar to lenses on the outside to increase light transmission.
Most are just clear.
Mark

 

[Rudi Herbert]

Gentlemen,

In the interest of being added to the e-mail list we have going on, please post your e-mails on the forum so any of us already on the list can add you to the recipients, otherwise you might loose a few important e-mails.

Ports: I don't think this is the culprit. They are either made from optical glass or acrylic, and the glass ones have anti reflective coatings inside and out, while acrylic does not since it can not take a coating. I have seen some great images from DSLRs using glass ports, and many of us here use glass ports. In fact, the worst example of this problem was shot by Michael Maes with glass ports, BUT I have also seen magenta stuff shot with acrylic ports. Yes, this could make a difference but not something so fundamentally bad.

I think the type of water makes a difference actually. Very clean, clear waters, with light penetration to depths unheard of to most people actually yield the magenta case even in the shallows, case in point Greg F's footage from Hawaii, not very magenta but without any color saturation whatsoever. Michael Maes encountered the same issue in Grand Cayman, again, a filming mecca reputed for the clarity of its water. Conversely, I have seen good results in the Florida Keys, whose waters are chock full of particulate matter, and so has Frazier encountered similar results. Ironically, Grand Cayman and Hawaii are dream destinations for photographers and other video cameras as well as DSLRs do as well as expected in those clean waters. The fact that the RED performs best in dirty waters makes me think the MX likes, or needs, heavy filtration that sort of disrupts the natural, bell shaped absorption of wavelengths that takes place in clean waters, sort of a mushing of the color channels together if you will.

Of course I could be way off, but having been looking at these images for many months now, I still cannot see a pattern emerge that can be repeated or recreated, so I'm left to conjecture, which although not a bad way to round one's opinions on the subject, tends to be as valuable as a sphincter sometimes....

 

[Graeme Nattress]

Thanks Rudi. If it's just an AR coating at most on the port, it's probably not it, and if other cameras can use same ports ok, then again, probably not it.

I think magenta might just be the specific balance, and the reduction in over-all saturation is the real issue that manifests as magenta under some light conditions.

And indeed, the variability of conditions is what makes looking at individual stuff hard, but now that I'm talking to you all I'm getting a bigger picture.

Graeme

 

[Dave Blackham]

Acrylic ports are usually not coated with AR, Glass usually does have AR coating. The optical characteristic is different underwater in that it has water one side (obviously) You need to be real carful for reflections within the port extender (the tube in which the lens is housed behind the port) being reflected back down the lens. Some lenses are fitted with a black mask to reduce this phenomenon. Domes are mostly used for wide and standard lenses, flat ports for macro. Flat ports tend to be acrylic but not always so. I have no idea if theres odd reflections of the IR filter or not but we need to ask all questions then eliminate them.

 

[Rudi Herbert]

Graeme,

You could be on to something with reduction in saturation. You know, if you just push the saturation slider down on Redcine on underwater footage that looks good, guess what happens? Yep, the whole image turns magenta just like the unrecoverable stuff. So yes, probably the magenta cast is a result of lowered saturation, but what causes that....

 

[Lee Saxon]

Man this thread took a crazy-ass turn, didn't it?

 

[Jon Shaw]

Actually Rudi you could be onto something as I don't seam to have the magenta issue that bad but generally I'm not in super clear water. When I have seen it has been in Tonga which has that ultra blue water.

 

[Johnny Friday]

2nd this as well....i had mentioned for me in locations with just brissling blue water and very clean is where it usually shows up. Which seems to lead again to is any UV or IR penetrating? or the IR filter causing an issue? I think with pulling off the OLPF and replacing it with a clear filter is another key test to do...