CUPERTINO, Calif. — Apple Inc. unveiled a new iPhone on Tuesday that is faster and more powerful but stops short of a more radical upgrade. It said Sprint customers will now be able to use one.

The new iPhone 4S has an improved camera with a higher-resolution sensor. The processor is faster, which helps run smoother, more realistic action games. It’s also a “world phone,” which means that Verizon iPhones will be able to useable overseas, just as AT&T iPhones already are.

There had been speculation that Apple would reveal a more radical revision of the phone, an “iPhone 5.” The no-show leaves room for speculation that Apple will reveal a new model in less than a year, perhaps one equipped to take advantage of Verizon’s and AT&T’s new high-speed data networks.

Apple’s stock fell nearly 5 percent.

Apple is including a “personal assistant” application called Siri in the iPhone 4S. It responds to spoken questions and commands such as “Do I need an umbrella today?” It’s an advanced version of speech-recognition apps found on other phones.

The new iPhone also comes with new mobile software that includes such features as the ability to sync content wirelessly, without having to plug the device to a Mac or Windows machine.

The iPhone announcement came during Apple’s first major product event in years without Steve Jobs presiding. New CEO Tim Cook led the show after Jobs, who has been battling health problems, resigned from the post in August.

Cook, wearing a navy blue button-down shirt and jeans, opened by calling his nearly 14-year tenure at Apple “the privilege of a lifetime.” Those in the audience clapped as he entered, but the reaction seemed more muted than what Jobs had recently received.

Cook said the latest iPhone, which came out in June 2010, sold more quickly than previous models, but the iPhone still has just 5 percent of the worldwide handset market. Apple is hoping to grow that with the new model.

Apple’s new mobile software, iOS 5, will also be available on Oct. 12 for existing devices — the iPhone 4 and 3GS, both iPad models and later versions of the iPod Touch.

Apple said Oct. 12 will also mark the launch of its new iCloud service, which will store content such as music, documents, apps and photos on Apple’s servers and let people access them wirelessly on numerous devices.

Apple said the new phone will come in black or white. It will cost $199 for a 16 gigabyte-version, $299 for 32 GB and $399 for 64 GB — all with a two-year service contract requirement. It will now be available through Sprint Nextel Corp., besides the existing carriers, AT&T Inc. and Verizon Wireless.

Pre-orders will begin Friday with availability on Oct. 14.

The previous version, iPhone 4, will now cost $99 for 8 GB. The 2009 model, the iPhone 3GS, will be given away for free with 8 GB. Both also require a two-year service contract.

Apple also touted the popularity of its products and unveiled a new line of iPods, including a Nano model with a multi-touch display that promises to be easier to navigate. Apple made no mention of its Classic model, which many people had speculated the company might discontinue.

The event took place in Apple’s Town Hall room, where the first iPod was launched a decade ago. Cook said Apple has sold more than 300 million iPods worldwide so far, including 45 million in the 12 months through June.

The iPhone came six years later and has gained millions of fans, thanks to its slick looks, high-resolution screen and intuitive software. There were 39 million iPhones sold in the first six months of this year.

Apple’s stock fell $17.15 to $357.45 in afternoon trading Tuesday.