With the iPhone having been around as long as it has, it's a bit surprising no one has come up with an affordable waterproof case that lets people use the device to take pictures and shoot video while snorkeling or scuba diving.
We saw the FourPro iPhone housing appear on Kickstarter late last year, but it didn't reach its funding goal, and it's unclear at this point if it's being produced. At any rate, with the Kickstarter failure, the retail price was expected to be about $700.
Its three mechanical buttons are designed to let users click the camera's shutter; switch between still images and video; and access the iPhone's home button. That's about it. There's no way to swipe the screen or use the keyboard (though you can apparently access Siri through the case -- which may well spawn a whole new bubbly subgenre of S--t Siri Says blogs on Tumblr).
The original idea seems to have been for users to turn on and unlock their iPhone, and then move the camera-app icon to the far right of the menu bar at the bottom of the screen so that once in the case it would sit beneath the appropriate mechanical button. Then users could seal the phone into the case. At that point, the phone could go to sleep and be reawakened underwater using the home button, and the Cousteauian fun could begin.
With the iOS 5.1 update, however, Apple made some changes to how the interface handles the camera icon and app, and TAT7's makers now instruct users of the updated OS (PDF) to turn off sleep mode altogether, which, of course, will affect battery life and also would seem to make one of the device's mechanical buttons superfluous. (You can check out a PDF of the device's manual here.)
There's also the issue of the phone being set up to automatically lock itself after a given time. Users would have to switch off any such automatic timers before heading into the deep -- or they might end up lugging around a useless device. (And users who have their phones rigged to receive work e-mails might not be able to turn off such a lock timer, if their employer's IT department forbids it.)
Still, if the 5.1 workaround doesn't give you pause, and the other restrictions aren't deal-breakers, then perhaps you're willing to spend close to $100 on a case that will supposedly let you switch on your iPhone, seal it up, tumble backward into the waves, and start shooting away. In that case, the TAT7 might be your gizmo.
There are one or two other caveats. You might want to consider maintenance issues (the makers suggest you "regularly apply silicone grease to o-rings and buttons" for proper seals and functionality), and then there's the warranty. As with warranties from other case makers, the manufacturer isn't liable for replacing your iPhone if something goes wrong. TAT7 will replace your case, but only if you find, before your first use, that it's defective.