I would like to mount a Black Magic Pocket Cinema 4K to my ROV. The camera and its cage need a minimum tube diameter of 10" inches.
Are there any solutions for a pipe and lens dome of that size?
Hi @kurtnelle, welcome to the forum 
Blue Robotics only sells up to 8" diameter enclosures, and 4" diameter domes. You’re welcome to use our drawings and CAD models as inspiration for a larger design, but you’ll likely need to make your own design and source the parts yourself.
It may be helpful to refer to the Under Pressure pressure vessel design software for determining suitable tube and dome thicknesses for the depth and water type you’re interested in filming in.
I would note that the Black Magic Pocket Cinema 4K is 178.1 x 96mm, and has rounded corners, so it should fit into an 8" enclosure if it’s ok to use it without the cage.
From a quick search online it seems that camera cages are generally used to make cameras easier to hold and to protect them from falls/damage. If it’s in an enclosure then you don’t care about holding it, so it’s perhaps acceptable then to just get some a mount/some corner pieces made (3D printed?) to support the camera and protect it if the ROV/enclosure somehow gets dropped.
Using an 8" enclosure would still require purchasing a custom dome, but at least that way you could purchase pre-made flanges, o-rings, tube, and the rear side end cap (depending on your depth requirements).
Hope that’s helpful!
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@Eliot, Yes it’s helpful.
One of the main reasons why I needed it in the cage is for the lens support. The lens I intent to use with it is ~ 3.2 inches in diameter. Is a dome even needed? I read somewhere that even a flat window is good enough. I’m not sure about the max water depth since there are no accurate measurements that I can access without measuring it myself, but I would think that 20 meters is the max depth. This is for filming a reef.
Edit: Erm. UnderPressure does not appear to run on Windows 11 
Could the lens be supported by a mount in the tube, rather than a cage attached to/around the camera?
“Good enough” depends on your requirements. A camera with its input at the centre of a dome will have a less distorted image than one looking through a flat window, but it’s possible the reduced distortion at the edges/corners isn’t worth the extra development/expense for you. I’m hoping to make a clear guide and possibly a calculator for that at some point in future, but in the meantime you may be interested in these web pages:
- Optics of Dome Ports
- Planar Interfaces and Apparent Positions
- https://www.deepsea.com/knowledgebase/underwater-imaging/dome-view-ports/
It’s also of course possible to try out a flat end-cap and see if the results are reasonable or if a dome is required.
Our 8" enclosures are rated to 40m depth, so 20m shouldn’t be an issue
Hmm, it is definitely an old application, but Windows is usually pretty good at being able to run old stuff. Is there a particular error you’re getting, which isn’t covered by the troubleshooting manual in the Documents and Downloads section?
If there is you can perhaps try one of the approaches suggested here, but I’d recommend checking the operating and troubleshooting manuals first
I think that a dome can be purchased outright. Further, I think the minimum tube diameter would need to be 9 inches since the camera is not symmetrical. I’ve done some quick and dirty measurements to find that if mounted along the central axis of the pipe, the right-hand grip will impinge upon the wall of the tube.
https://www.bhphotovideo.com/c/product/1283261-REG/ikelite_75340_dl_8_dome_port.html
(I’m still looking at the pressure calculator thing)
Another concern that I have is heat. Is there any solution to cool the inside of the tube while at depth? The BMPCC4K puts out a lot of heat and I doubt that the thermal conductivity of the plastic tube will be enough to keep the air inside cool.
Nauticam makes very good enclosures for the Blackmagic Pocket Cinema: it might be easier just to buy one of these with the proper dome for the specific lens you’re using if you have the budget for it.
However, have you considered reducing the size of the camera? Unfortunately I haven’t had the time to finish the project, but I’ve made some progress in breaking the camera down to its different components and mounting it inside a 6’’ tube. Preview would be via a program called decaffeine running on a Raspberry pi, and the same Rpi would be running a program for controlling the BM camera via bluetooth.
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Very possible, I haven’t looked into large domes so wouldn’t know
That wouldn’t make a difference if you go with a flat port, but a misalignment between the lens and a dome would definitely add some distortion, although I don’t know how much or how difficult it would be to correct for.
That one’s hard to know without testing. Given the large enclosure size, an aluminium end-cap at the rear would definitely help with temperature. Normally for for temperature-sensitive applications we’d recommend an aluminium tube as well (which we don’t sell in an 8" size), but it’s difficult to provide meaningful recommendations without knowing more about the energy going into and out of the system (e.g. how much heat the camera emits, and things like water temperature in your intended operating conditions).
I expect breaking down the camera into parts like @Skredfare has suggested could help quite significantly with space and temperature, but there are also understandably some risks involved, and it likely makes the camera harder to sell down the track (unless you find someone with a similar application).