Underwater Bubble Blowin' Users Group

[Johnny Friday]

Two other things you can do for condensation are silica gel packets and also getting canned dry air or nitrogen and shooting it into the housing just before you close it - displacing the moist air.

Johnny/Ken: Question? I think I put vacuum ports in your housings, did you guys pull a vacuum for test and does that help with condensation?

(Note: the idea of the vacuum port is a small bicycle type valve (schrader valve) in the housing. To test that you have a seal, you use a small handheld vacuum pump to pull a vacuum on the housing after you close it. If there are any leaks, the vacuum will drop off quickly. You use vacuum because it is much safer than pressurizing the housing.

Hi Mike,
I wasn't aware of the canned air. I'll try that next time. We did not pull a vacume, but only because we had the rubber line crack on us somehow. I think Ken got a vacume on it, but then somehow the line got pinched and cracked. But is a great idea and a great piece of insurance. I now use a vacume guage on any and all of my housings before dunking the camera. Saved me once already.

 

[Pawel Achtel]

Hi Mike,
I wasn't aware of the canned air. I'll try that next time. We did not pull a vacume, but only because we had the rubber line crack on us somehow. I think Ken got a vacume on it, but then somehow the line got pinched and cracked. But is a great idea and a great piece of insurance. I now use a vacume guage on any and all of my housings before dunking the camera. Saved me once already.

Keep in mind that any pressure change inside the housing will affect the back focus, which would have been calibrated at ambient pressure :whistling:

 

[Michael Hastings]

Keep in mind that any pressure change inside the housing will affect the back focus, which would have been calibrated at ambient pressure :whistling:

Not arguing, but can you explain - how does the pressure (probably only 10psi - max 15) difference change the backfocus if the pressure is equalized? Is it the three or four inches of air that you would be shooting through normally that now is a vacuum that is having an optical effect? Or would it be something physical actually changing the backfocus distance, similar to heat expansion/contraction? Any way to quantify and therefore compensate?

PS Glass 8" domes arrived about 2 weeks ago. Was too busy last week and this week to design the dedicated front plate so a couple weeks until ready. (Dedicated front plate isn't much more expensive than making an add on to the normal plate AND it allows us to have the opening even larger. Opening on standard frontplate is quite large - accepts the Arri 8R - but is just about a quarter inch too small to allow use of the 10mm Ultraprime.) Beautiful Hoya glass with nice AR coating. I'll post a photo tomorrow.

 

[Pawel Achtel]

Refractive index of vaccum is 1.0000, refractive index of air at 30in Hg pressure is about 1.0003. When you focus on virtual image plane behind a dome port, due to very short DOF, this change may be significant.

This could explain why all of the IMAX shots taken below 300ft that I have seen were very soft and looked out of focus to me. But, maybe it was something else. :blink:

 

[Michael Hastings]

Refractive index of vaccum is 1.0000, refractive index of air at 30in Hg pressure is about 1.0003. When you focus on virtual image plane behind a dome port, due to very short DOF, this change may be significant.

This could explain why all of the IMAX shots taken below 300ft that I have seen were very soft and looked out of focus to me. But, maybe it was something else. :blink:

So if you found that a good fixed setting for say an 8R, UP 10, or 12mm was 15" how much would the vacuum/RI 1.0000 to 1.0003 change that?

Why would the below 300 feet matter - were they pressure compensated housings (i.e. air or whatever was introduced under pressure to offset depth)? Most housings are just whatever pressure they were closed at and stay that way regardless of depth - unless of course there is a leak!

 

[Pawel Achtel]

So if you found that a good fixed setting for say an 8R, UP 10, or 12mm was 15" how much would the vacuum/RI 1.0000 to 1.0003 change that?

That, I don't know. But I do know that when I installed internal wheel filter on F900, which was just 0.1mm thicker, all focus was way out on three colours. There was no way to focus the camera at all. It makes me think this is very critical part of the lens.

Why would the below 300 feet matter - were they pressure compensated housings (i.e. air or whatever was introduced under pressure to offset depth)? Most housings are just whatever pressure they were closed at and stay that way regardless of depth - unless of course there is a leak!

Not IMAX housings, no. Howard Hall injects air (or Nitrogen) with depth (and purges it on ascent). His IMAX housing would crush in just ~30m, I think. So, there is more than 30x the atmospheric pressure inside the housing at the bottom. This would be very significant. And, I think, this is the reason those images are so soft. Have you seen them, BTW? If not, watch them. I have seen SD footage sharper than this. Seriously.

BTW, Have you seen hot air changing refractive index? Warm air is less dense than cool air, and the variation between the hot air at the surface of the road, and the denser cool air above it creates a gradient in the refractive index of the air.

Lastly, the changing ambient pressure is not very good for the lens, which would suck in moisture and dust on each test. Unless it is a Master Prime (sealed).

 

[Johnny Friday]

Well, all that said and i can tell you that I have not experienced focus issues when i've pulled a vacume on my housings. I've not gone beyond 4 or 5 atmospheres though.

I expecet what you are saying is true, but to what degree and at what ATA would you expect unreasonable fall-off?

 

[Pawel Achtel]

Well, all that said and i can tell you that I have not experienced focus issues when i've pulled a vacume on my housings. I've not gone beyond 4 or 5 atmospheres though.

I expecet what you are saying is true, but to what degree and at what ATA would you expect unreasonable fall-off?

I am pretty sure you haven't gone past -1 atm (~101kPa) pressure difference :biggrin: You can't pump vacuum beyond 0 atm (or -1 atm relative pressure) because the ambient atmospheric pressure is 1 atm. It is not possible and this is just basic law of physics. You can only pump positive pressure above 1 atm. This is what Howard Hall does.

Secondly, wrong back focus does not mean your pictures will be out of focus. If you are focusing using screen or view finder, they may be OK as long as you can actually see the critical focus on the screen, which with wide angle you can not :blink: . The back focus affects focusing using witness marks, which is essential in larger formats. This is what I was referring to.

What camera have you used and how did you focus? Can you post some frames (crops).

BTW, I am yet to see a single frame from underwater footage taken with RED that would be sharp and almost as good as some respectable topside footage we see on this forum.

 

[Mark Thorpe]

BTW, I am yet to see a single frame from underwater footage taken with RED that would be sharp and almost as good as some respectable topside footage we see on this forum.

Wait a few more months, cogs are turning......

 

[Pawel Achtel]

Wait a few more months, cogs are turning......

he he he, you beter be quick, mate. It would be a disgrace if I beat you to it. :bleh:

Attached is the picture of CinePort-MP14. It started as 60lb block of Titanium grade 5 (!!!). This is significantly different than your garden variety grade 2 alloy. Anyway, the raw material, apart from costing more than brand spanking new AquaVideo housing, was machined at a special air-space/military facility in Adelaide to a shell weighing mare few pounds and wall thickness of 1/8" and precision of 0.05 mm - a bit of rocket science.

Five new pieces of CinePort glass have just been coated, passed individual QC and are on their way across the Pacific.

Witnes marks (focusing distance) conversion for combined CinePort optics has been completed (I am still curious how you guys intend to focus underwater).

Lens servos are already done. Now working on the titanium back plate.

Cogs are turning here too :construction:

 

[Johnny Friday]

he he he, you beter be quick, mate. It would be a disgrace if I beat you to it. :bleh:

Attached is the picture of CinePort-MP14. It started as 60lb block of Titanium grade 5 (!!!). This is significantly diferent than your garden variety grade 2 alloy. Anyway, the raw material, apart from costing more than brand spanking new AquaVideo housing, was machined at a special air-space/military facility in Adelaide to a shell weighing mare few pounds and wall thickness of 1/8" and precision of 0.05 mm - a bit of rocket science.

Five new pieces of CinePort glass have just been coated, passed individual QC and are on their way across the Pacific.

Witnes marks (focusing distance) conversion for combined CinePort optics has been completed (I am still curious how you guys intend to focus underwater).

Lens servos are already done. Now working on the titanium back plate.

Cogs are turning here too :construction:

Pawel, very nice stuff man. By the way when i was referring to ATA in depth you misunderstood me....i meant me diving at that ATA---not the housing pressure inside. Just want that to be clear since there is some misunderstanding in many of the posts.

As for focusing etc....I just use my good old fashioned eye. Of course I did many tests underwater finding set points for focus distances as well as a hyperfocul setting.

Myself and a few others have been shooting red for a variety of documentaries and we are pleased with the outcome of our tests to prores 422 as well as to the big screen. Not every shot can be a mastered Ansel Adams shot....although we all strive for perfection as you must know being a professional shooter you don't always get a perfect shot everytime---well maybe you actually do and that is why you post the way you do and it offends you to see anything less---which in that case is understandable no?

I Like all of your Nasa gear--very nice, the best that money can buy and only a few can afford. Should be finished about the time Epic comes out no? In the meantime I guess I and a few others will just have to do the documentary work we are doing and hope for the best.

 

[Mark Thorpe]

Johnny my man. I saw some of the imagery from your recent shoot mate. Good stuff. I am also relying on my eyes to get this work done. If the plan comes off we been discussing I think we will be able to jointly share the fruits of that labor with the rest of the gang here.

'til then Mum's the word. :greedy:

Cheers,
Mark.

 

[Johnny Friday]

Johnny my man. I saw some of the imagery from your recent shoot mate. Good stuff. I am also relying on my eyes to get this work done. If the plan comes off we been discussing I think we will be able to jointly share the fruits of that labor with the rest of the gang here.

'til then Mum's the word. :greedy:

Cheers,
Mark.

Mark,
You know me amigo.....i would gladly share imagery with you Russ, Ken, Aqua and others that would look at it and comment constructively. It's one thing to share views constructively and another to just rip into people and their images with nothing but negativity with nothing constructive to say.

I respect what many have to say in this forum. That said I think it's a forum to help with the tools we have in our hands and those that are accessible for the majority of us. Their are the high enders such as Pawel that have a time and place, but let's talk reality as to what most of us work with and can afford---especially when times are a changing every year and equipment changing with it.

Look forward to more with you soon in Indo or Africa Mark. Looks like that's a wrap with the nat geo project for me and now i have time to work on imagery in La Paz---now's the time here for the big stuff. I'm also working with FCP server and using as my stock imagery logging device. Having a time working out some advanced settings, but it will be great for archiving stock.

ps...I'll be the first to admit that what we shot in Alaska was not the best stuff when it comes to CA and low light conditions/shooting. BUT, it was all shot at the limits of our gear and climactic conditions. The topside is unbelievable. U/W---well, now i know why you don't see a lot of u/w docs in the pacific northwest under the conditions we shot---loads of planctonic bugs, low visibility and just plain dark, dark water. This truly stretched the RED and any camera to its' limitations. We had loads of CA and found out many cans and can-nots. We've shared them with many of you personally. BUT sure looked great after post and in 422 prores and even as great on the big screen with the selects....I'll let KC comment further as i think that's about all i can say being the low man on the totem pole as a mere camera operator.

 

[Russ Campbell]

Hey Johnny. Agree with you wholeheartedly. I am really looking forward to getting my RED underwater next month. Should be 'Raggie' season at Aliwal. As you mentioned, we will get down to doing the filming now regardless of the bit of CA under difficult lighting conditions and 'soft' images that the great underwater photographers have had to put up with over the years. I will happily get my NASA housing when NASA employs me. Until then, we will have to be content with having our footage shown on NG or BBC:wink:

 

[Pawel Achtel]

I will happily get my NASA housing when NASA employs me.

They will only employ you if you are worth it. If you are worth it, then you are better off employing yourself. If you cannot afford something, it means you are not worth it - tough, but true.

Until then, we will have to be content with having our footage shown on NG or BBC:wink:

They will not pay you enough to do this properly.

I am not criticising you guys for the sake of it. I am struggling to understand why would anyone film with a 4k camera (with all the cost and difficulties associated with it) where a superior result can be achieved with consumer grade camera (albeit this conclusion is not immediately obvious or easy to accept by most people). In my view, unless you actually go through a lot of trouble, cost and effort, the mere fact of shooting 4k has no benefit whatsoever. The limiting factors (even with HD) are the optics, lighting, and many other features apart from sensor resolution and camera qualities. Just trying to help make it economical for you, that's all. I always give my honest opinion. But, if flattery makes you happy... :biggrin:

BBC and Nat Geo do not pay much, if anything. They are in a business of making money and paying you as little as they can get away with or less. BBC would not even look at my footage. They can't afford it anyway. If BBC and Nat Geo are your goals, you should be spending money on pitching your ideas to them rather than making good pictures or capturing unique animal behaviour. I decided to do the later and never look back :biggrin:

 

[Michael Hastings]

Using titanium doesn't make it a NASA housing. I've sold multiple housings (most of them PVC!!!) to NASA on multiple occasions starting in 1986. You can see an AquaVideo housing near the beginning of one of the IMAX Space shuttle films in the Neutral Bouyancy Lab in Houston (IMAX Dream is Alive or one of those). They appreciated the corrosion-proof and nearly indestructible nature of the PVC housings and SPECIFIED dome ports.

I've sold a pretty good number of RED housings (mostly aluminum because that's what they wanted) and probably could have charged $15K instead of the $8499 price and most would have paid it, but I try to price fairly relative to the cost and time involved.

I'm still trying to understand the great advantage of the Cineport? Looking at the drawing it looks as if it is just a portion of a 300mm (approx. 12") diameter dome port. Very nice, but we have access to these from multiple sources at reasonable prices (sub $3K end user).

And it seems that your design limits it to use with the 14mm or greater focal length - kind of strange to say a 14mm Master Prime is a limiting factor but there are many situations where a wider lens of slightly less optical perfection like an 8 or 10 Ultraprime (or god forbid maybe even some superwide still lenses) will provide a better result by allowing shooting through MUCH less water.

While I wouldn't argue too strenuously against the premise that the inherent CA and curved focus plane of dome ports with extreme wide angle lenses probably limits the resolution to less than the 3.2K (this is the commonly accepted actual "debayered" resolution) of the RED. And remember CA is easily corrected in software for still photos and this capability will certainly become practical for RED footage in the not too distant future.

However, I would argue against the premise that therefore we might as well shoot with some cheaper hidef camcorder. Many of these people spent 14K or more for a Z1 and housing (and most of that was for a housing which has a high level of depreciation) and current equivalents like the EX1 are even more expensive, so spending $20K on a camera $9K on a housing and $5k on optics (birger and some excellent canon glass) isn't out of range at all. Especially since those optics (while maybe slightly less quality than the Master Primes) are probably equal or superior when used on the RED compared to any of the $20K+ plus HD B4 lenses, and VASTLY superior to the builtin lens of a prosumer camcorder with a wide converter.

The other part of the equation is that regardless of the limitations of relatively cost effective wide angle lenses/underwater ports for the RED - there are no such limitations for closeup and macro shooting where you are using extremely sharp longer focal length lenses through flat ports and very little water - which can easily resolve more than 4k.

And even with wide angle, many shoots happen in clear water conditions at higher f-stops, which can offset some of the limitations of the wide angle/dome setups.

 

[Pawel Achtel]

Aqua,

As usual, the devil is in the detail and I think this is largely where we may have different or possibly same views. CinePort is not a traditional piece of glass. There are only few facilities in the world that can manufacture it. It is something that took a decade of engineering approach to perfect. The key word is optimisation and this is where it is revolutionary. The concept is 100 years old. The execution is not. Its strength, like with most optics, is in designing and matching various parameters and executing the design with superior surface finish and tight tolerances. Most of those properties are not immediately obvious when you look at the final solution, so there are two ways you can judge it: by looking (analyzing) images or trust me (which I know you won’t :w00t: ). For the time being I have only HD interlaced images. I would not hesitate to put them for comparative analysis against any 4k wide angle underwater footage out there - even just for fun.

Regarding angle of view, yes it is limited to 14mm (on S35) view or less and this is to achieve the best image quality possible. I would rather compromise the angle than the overall quality. You can go wider, but then you start getting considerable CA and out of focus corners very quickly. You are beter off shooting through some more water at some point and, this is the point.

I remain unconvinced that still lenses, while theoretically viable, are reasonable solution for wide angle underwater cinematography. I have three CinePorts that can use 14mm f/2.8 Canon prime (using Seacam mount). I decided not to use them for various reasons; one of them is difficulty in adjusting critical focus? Although, the image quality should be pretty good and better than that you can achieve with most underwater still camera setups. If you have a client wanting such solution, PM me offline as I no longer have a need for them.

As to PVC housings; well, I tried them in the past and I find it more economical to spend money on something that is perfect, rugged, that will last lifetime with any camera and hard professional use. Cooling is one major problem with PVC. I don’t say they are not good for some odd wet jobs. To the contrary, there are many uses where such design has merit. It is just not what I would use for my work, that’s all. Also, you cannot design an equivalent lens mounting part out of PVC. It would break in less than 10m of water. The titanium piece is good for all extreme diving depths, light weight, it will never scratch, it will never corrode and it will reliably seal for 1000 years.

Regarding flat ports, yes they work great and offer practically no significant loss of quality for macro work. They are also next to impossible to get the focus right in 2k and 4k takes this challenge to a new level. A good friend of mine, Dave Hannan is a master of underwater macro. He uses motion control, periscope snorkels, 4-axis rigs and special macro lighting - very impressive stuff.
He uses 2/3" for all his macro. One good reason S35 is not best for macro is that DOF for an object 5" off the lens is ridiculously small.

My cup of tea is wide angle. And, whilst I still shoot a fair bit of macro, the vast majority of cost and effort go into wide angle setups.

 

[Johnny Friday]

.....Agreed Pawel....
I'm going to see about applying as baggage handler for you to learn the ropes.

I doubt anyone is looking for praise. Far from it. Solutions man. But lest we stray too far from the path. what you said is a bit idiotic about working for bbc and nat geo. many a good camera operators have worked for them and still do--Possibly none of your caliber--i think you are a one of a kind---you place yourself in a class of your own amigo... Yes, they probably could not afford you, but you don't seem much the team player anyway. So can't imagine you working on a production where a team counts. I do see you as a one man king of underwater imagery kind of guy....but the picture of that is not pretty.

by the way, MP's are not the only solution and you've been schooled on this already. There are professionals out there I respect and know of their work that have had tremendous results with still lenses....Nikon in particular. These are just guys i know and respect and have access to MP's and UP's. They've done the work and not just touted as you do that only cine glass is appropriate for 4k work. I won't argue your points, but i'm working now and booked for a number of projects. Yes, we've put our work up on a large screen and the results are stupendous. Yes, we trash a lot of shots. But don't you? Maybe not. You probably shoot 90% keepers eh?

Anyway, happy with my results and the execs are to so yes i guess something is working. But just as you Pawel we are striving to produce better images all the time. You offer very little to this forum except a bloated ego. I'm sure i'm not the only one with that opinion. But had to get it out....sorry but it's true and not meant to be anything other than constructive towards you. I want you to be better Pawel and to strive for perfection--not just with your images, but as a talented and masterful image maker that gives this forum something useful......ha, that'll be the day. hey, all joking aside....Thanks for nothing.

 

[Pawel Achtel]

.....Agreed Pawel....
I'm going to see about applying as baggage handler for you to learn the ropes.

You are always welcome to join on any trip (http://achtel.com/Trips/). Actually, the vast majority of people I worked with loved it and are waiting for more. I do like working in a team. The atmosphere is always very relaxed and humourous; much more than on any other professional shoot. :biggrin:

You probably shoot 90% keepers eh?

It largely depends on surge and current. Wide angle, yes on average I can nail it close to 90% of time sometimes better. But macro; I struggle to get 10% shooting ratio - and that's HD. Many others do much better than that and that's mostly with lesser cameras :bleh: But, on a rare occasion when I get the focus right :blink:, it is nice. I like the results.

Unlike most others, I like shooting in poor viz, murky, green, cold water.

... but as a talented and masterful image maker that gives this forum something useful......ha, that'll be the day

Sorry my comments weren't useful thus far. Oh well, I can only try to improve :biggrin:

 

[Mark Thorpe]

They will only employ you if you are worth it. If you are worth it, then you are better off employing yourself. If you cannot afford something, it means you are not worth it - tough, but true.

It all depends to what approach you take. I am employed by National Geographic on a one year renewable retainer, so I guess I am worth it. Some people just attack what they can't get I suppose, maybe they are not worth it also :bleh:

Wanting something but not being able to afford it comes down to simple economics, Save and buy it, period. Your notion of not being being worthy to have that which may be out temporarily of your financial grasp is demeaning, derogatory and is an affront to the majority of people here. I guess we cannot all have the talents which you have obviously mastered but I am sure that us minions prefer our out of pocket camaraderie above alienating ourselves, as you tend to do very well.

Until we can all sit around and pore over some 4k stills supplied by you I guess there will always be skepticism regarding your claims as to the effectiveness of your exclusive CinePorts. Please supply us with these stills as the ones on your site are just thumbnails and obviously don't allow us to get an accurate idea of the benefit of using these ports. All we have is your word at this moment

Until then I'm going to dream of attaining your level of self proclaimed dominance in this chosen filming genre.

Dive safe,
Mark.