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JohnE

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JohnE last won the day on January 11 2017

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About JohnE

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    http://www.GatesHousings.com
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    San Diego, CA

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    GATES -- All Models
  1. Good writeup. The perspective and corner pulling section is insightful. Personally I prefer the shot of the motorcycle wheel pulling a bit in the corner as it adds dimension.
  2. This is a good discussion of underwater optics trade offs. Interchangeable lenses or built-in? Wet optics or dry? Zoom range? Lots to consider. As bill1946 points out, optical versatility is one of many reasons small camcorders / housings are a popular choice for underwater video. The Sony AX700, for example. The internal lens 35mm equivalent is 29mm to 348mm (just optical zoom). 29mm is not really wide, so a Wide Angle Port opens that up and retains nearly the entire zoom range. And it gets better. Add a SAGA flips diopter kit to the Wide Angle Port, and you add macro / super macro to the range. No ILC system comes close. One more comment about camcorders: they are designed and optimized as proper video platforms. Not a photo camera that also acquires video. The UI is different: how you hold it, shoot it, what buttons are accessible, etc. Internally the camera has video-centric features like optical image stabilization, 4 hour battery life, multiple SD card slots, one-touch WB, and subject tracking focus (watching the camera track an octopus across a reef is surreal). And whatever magic Sony has put into the camera, the AX700 requires no white card to perform an AWB. Amazing. If you're serious about shooting underwater video, consider carefully the tradeoffs. J-
  3. The MLA60 debuted at Wildscreen this week in Bristol. Find out more on Facebook and Instagram. Anyone shooting Monstro will be happy. The lens covers the entire 46.3mm sensor image circle.
  4. Hi all, The Gates Z100 housing is indeed sold out, and we have no plans to make more at this time. That said, if someone insists on the Z100 as an acquisition platform, we can discuss options to make one as a special run. And FWIW, those of you shooting on a proper video system like the Z100 appreciate and understand the benefits: Long battery life, recording bitrate / color space, instant auto-focus, versatile zoom range (especially when paired with a proper zoom-through port), external monitoring, and more. But many people have moved to DSLR / Mirrorless systems. Some have legitimate reasons e.g. shooting photos / video both topside and underwater. Others have done so because it's popular. Still others simply migrated to photos because it's easier. Video acquisition, editing and storytelling is hard by comparison to the instant gratification of photography. So kudos to all of you that take on the task of filmmaking. J-
  5. We tested the 17-70 w/Epic camera. Even at 70mm it focuses right up to the dome. While this may be insufficient for the smallest critters, it's a remarkably versatile. J-
  6. Seal Check is an active, external vacuum monitoring system. It allows you, the user, to make a go/no go decision on housing integrity by monitoring the vacuum level in the housing. An internal vacuum check takes this decision from you. You must trust the designer of the kit. We opted for the external system because other factors can influence the result. Temperature changes, for example, change the level of vacuum in the housing (PV=nRT). The smaller the housing, the greater effect temperature changes will have on the system. Also the larger Gates housings take forever to pull a reasonable vacuum with a hand pump. An electric pump is necessary. Great thread, this is good stuff.
  7. Thousands of PSI. Way beyond normal diving depths.
  8. For anyone interested in History...... The vacuum check idea goes back at least to 1993. Howard Hall needed a way to verify integrity of the IMAX Salido housing containing 3D camera equipment worth $2,500,000. The vacuum system was devised, and indeed resulted in a safe dry camera every time. He and Bob Cranston have since employed the vacuum checker on every underwater housing. 2003: Gates designed and built 2 custom F900 housings for Bob and Howard which included a vacuum check port. It was our introduction to the system. Shortly thereafter it became part of our standard factory test. It allowed quick identification of leaks, but more importantly it revealed a way to test for shallow water leaks a.k.a. the dreaded rinse tank failure. This experience led us to standardize 3 different vacuum and pressure checks on every housing to weed out all failure modes. Gates 'productized' the system in 2007 with the fitting name Seal Check. It was introduced in tandem with DEEP RED, our first cinema-grade system. We felt customers would appreciate peace of mind knowing their $50K+ camera investment was safe *before* entering the water. Seal check has proven itself many times, averting disaster from mistakes, abuse and damage (like from security inspections) that we all know happens in the field. For professionals it has not only saved equipment, but their production and paycheck as well. When you have to come back with the shots, failure is not an option. As noted by others in this thread, the obvious benefits have resulted in the vacuum check system being adopted by nearly every manufacturer and several dealers (e.g. Backscatter). Final note: The vacuum check system may extend all the way back to the 70's. I'm asking around to find out more.... Cheers, J-
  9. If you were able to pull a complete vacuum on the housing, it would be equivalent to 33 feet / 10m of water. But vacuum checks are much lower, so your observation is correct: the pressure difference from vacuum becomes and increasingly smaller part of the overall differential as you go deeper. However.. once an o-ring is engaged under pressure, it will only fail under two conditions: * Extreme pressures. A housing will flex and warp under extreme pressure, changing the o-ring groove characteristics, and resulting in a leak. This will happen long before the pressure increases to a point that the o-ring actually extrudes. We have tested housings to such depths here at Gates, and have interesting examples of how things fail. * Mechanical change in the o-ring seal. An impact, for example, to a plexiglass window, or the previously mentioned gland. Leaving a vacuum in place after checking the seals keeps the o-rings energized. It keeps everything tight while you are gearing up and getting in the water. And also while in the rinse tank -- one of the most notorious places to incur a leak. J-
  10. Great to see you at SDUFEX Dustin. Congrats on your selection, it's terrific. John
  11. Some info to consider..... The orange silicone o-rings used by Gates require no lubrication, including installation. Using silicone lubricant can not only attract dirt, but the o-ring will swell and could lead to other issues. Black o-rings are usually, but not always BUNA. The blue ones from Sea & Sea are, I think, flourosilicone. The lube they provide is compatible, while others in general use may not be. So....You should always follow manufacturers instructions for lubrication. Deviations might not be pretty (and we've seen them). J-
  12. As David points out, heat dissipation is important when dealing with these bleeding edge cameras. But the main driver of housing size is far more basic: buoyancy. If you have an aluminum housing glove fit to the camera it would sink like a rock. To offset that would require adding air space via foam, tubes -- whatever. So we just make the housing larger to balance everything. You then get more space for other things e.g. controls, cables, and your hands for service. J-
  13. If you can live with 100 feet max, Gates has a POV camera / housing: http://www.gateshousings.com/housings/hmr1...10-pov-housing/ Contact us here if you'd like to discuss further: http://www.gateshousings.com/support/contact-us.php Cheers, John
  14. Nick -- what features are of particular interest? Higher frame rates? How often will you use that feature? And it has AVCHD recording format, not something attractive to broadcasters. And until it's really 4K it's of no interest to Digital Cinema. Lastly, Canon has a huge suite of lenses to support their cameras. And more coming. Plus the low light sensitivity, and those are powerful features. J-
  15. It's going to be an interesting year. FYI the Gates C300 housing accommodates the new Canon C500 as well. We are crankin' here..... J-
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