The iPhone OS 4.0 was previewed today during an Apple Live Event. Steve Jobs was onstage live to introduce the next generation iPhone OS, with over 100 new features and 7 main “tentpole” features. Upgrade pricing (if there is any) wasn’t announced. If you’re a developer, the iPhone OS 4.0 SDK is already available for download and there are already photos and tidbits about the new OS scattered throughout the blogosphere. The rest of us will have to wait until summer to get our hands on the new update. iPad owners will have to wait until this Fall for their big OS 4.0 update.

iphone OS 4.0 preview AppleWith over 100 new features — some of them really, really cool — how much of an upgrade your iPhone or iPod Touch gets depends on the hardware you have. Not all iPhones will upgraded equally. The older generation iPhones will be able to run “many things” in the new OS, but won’t benefit from all of the new features. For instance, the older phones won’t support the multi-tasking features. According to Apple, the first generation iPhones and iPod Touch models aren’t able to handle the new OS and won’t be supported at all. Good thing I’m planning to upgrade my hardware this summer.

There are some cool new updates that effect iPhone photography. Developers will be able to access over 1500 new APIs as well as access to over 2000 APIs for hardware-accelerated math functions. Translated from geek, this opens up features in the OS that have prevented App Store developers from developing photo apps that are truly on par with Apple’s own apps.

Apple’s Camera App will finally have 5X digital zoom, although there was no word on whether this was true digital zoom or in-app cropping. On the 3GS (and newer iPhones), the Camera app will now support tap-to-focus in video. There is better support for geotagging in the Photo Library.

With the new Folders feature, you’ll now be able to have 2,160 apps on your iPhone (It’ll be tight, but that should cover me… 😉 ). Folders can be moved from screen to screen and can even be placed in your iPhone’s dock. Each folder can hold up to twelve apps, which means all of your Photography apps may be spread across folders called Photography 1, Photography 2, etc. No word yet on whether you can rename the folders or not.

The new OS will have Fast App Switching. While not true multi-tasking, this will allow you to save the app in its current state into the background. When you switch back, the app is where you left it, which should greatly reduce the time it takes currently switching between apps. Restarting your apps will no longer be necessary when you need to move from one to the other.

Task Completion will allow you to finish a time-consuming task in the background while performing another. It’s a form of multitasking. For instance, you’ll be able to upload images to Flickr in the background while you use another app in the foreground.

Unfortunately, this pretty much is the end-of-life for the older 2G iPhone and limits the full functionality of the 3G series. My old 2G is almost 2 years old and has served me well since the dawn of the 3G. This update won’t render it completely obsolete. The older iPhones will still function very well as phones, PDAs, cameras and voice recorders. The versions of apps will that work now will still work great on the older phones. I’ll still have all of the functionality I have with my iPhone today.

But those who don’t or can’t update their OS will quickly find themselves being shut out of new apps and updates that come available. These apps, which take advantage of the many new APIs may not run or even download to an iPhone running the older OS.

I’m excited about the new multitasking capabilities of the new OS. I seem to recall reading somewhere today that the new APIs will allow third party apps better access to the Photo Library, which could mean camera apps which save full-res images with the same speed that Apple’s Camera currently does. I love the new Fast App Switching which will let me “park” an app such as a camera but always have it at the ready — without any significant battery drain.

If Apple’s release pattern stays consistent, we should see some sexy new iPhone iPhone hardware released about the same time the new OS is publicly released.

With the new OS, the potential iPhone 4G (or iPhone HD or whatever Cupertino decides to call it), and the success and growth of the iPad, this is an exciting year for Apple, the iPhone and iPhoneography.