CUPERTINO, Calif. — Apple 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 usable 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.

There had also been speculation that Apple would include a chip that could talk to payment terminals at retail stores, turning the iPhone into a “mobile wallet.” Competitors are starting to include this capability in their phones, though the payment systems are still immature. Apple made no mention of such a feature in the iPhone 4S.

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.