Today’s smartphones have come a long way when it comes to photography and video footage. The iPhone 4S has a stunning camera, as do many other Android and WP phones out there. This is a great start, but wouldn’t it be nice to see even more improvements? Luckily, accessories like the Flash Dock can add even more great functionality. So what is it all about? Basically, it allows you to hook up an iPhone (or even other phones) to a DSLR camera via the hotshoe. This is normally used for external flash units and other accessories.
So why would you want something like this? It can give a professional photographer many unique features for the camera, such as geotagging, vibration monitoring, acting as a light meter, and a heck of a lot more. The limit is pretty much up to you and the apps that you want to use with it. This will certainly make your camera much more useful and powerful than ever before. This might not be for everyone, but it certainly is an interesting idea at least. You can get ahold of the attachment from pocketDEMO for just $39.95. If you already have a smartphone and a DSLR camera, why not?[ source ]