Apple had few surprises on Wednesday when it unveiled the new iPad, which the company hopes will maintain its stronghold in the tablet market and keep its gathering rivals at bay.

Many of the changes — a sharper screen and camera, 4G capability, a faster processor, and even the March 16 release date — had been on the speculation circuit for months. A couple other expected changes — a new name and Siri, Apple’s AI personal assistant — didn’t materialize. However, Apple left no doubt that its latest tablet — priced at $499, the same as iPad 2 — is aimed squarely at users who have unhooked themselves from the PC and are comfortable having a range of media devices to meet their growing and varying demands.

Taking the stage for his announcement in San Francisco, Apple chief executive Tim Cook touted the iPad’s success in the consumer and enterprise market. The iPad, Cook said, “is the ultimate poster child of the post PC-world.”

Though the price and the screen size haven’t changed for Apple’s new iPad, the updated tablet boasts the high-resolution retina display of the iPhone 4S and access to super-fast 4G LTE speeds. It also features a sharper camera (5 megapixels) and offers voice dictation in four languages, using a keyboard microphone. But 4G users will get one less hour of battery life and a higher purchase price. Adding the faster network support increases the cost by $130. Apple also announced that the price of the iPad 2 would drop to $399. And Cook pointed out that the company’s App Store now lists more than 200,000 apps for the iPad.

In Apple’s presentation, Cook and other executives highlighted the tablet’s screen, using the new iPhoto app for iPad and more advanced video games to show off the improved graphics.

“For Apple, it’s not about the specs,” Gartner analyst Michael Gartenberg said. “They’re not going to show off specs, but features. Competitors can match the specs, but not the ecosystem that Apple has spent years building out.”

Cook, who wore a black, untucked dress shirt, also announced upgrades for Apple TV, which will enable 1080-pixel high-definition content and iTunes in the Cloud, which will now support movies.

For months, technology enthusiasts have been buzzing about what Apple had up its sleeve for the iPad. With the new features, Apple is focusing on staying ahead of competitors in the tablet market — one the company single-handedly popularized with the 2010 introduction of the original iPad.

The iPad 2 followed a year later. To date, the company has sold 55 million iPads, and there’s no question that Apple’s tablet rules the market. But the company has noticed its market share shrink as competitors moved to flood the market. According to IDC, Apple’s market share fell from 87 percent to 68 percent in 2011.

Amazon’s Kindle Fire, in particular, has succeeded where other competitors have failed by pricing far below Apple’s starting point of $499. The smaller, cheaper tablet shipped around 5 million units in its last quarter and is estimated to have taken 14 percent of the overall worldwide market since its November launch, according to research firm iHS iSuppli.

In September, the Gartner research firm predicted that Apple will continue to lead the market at least through 2015, but that Google’s Android tablets as well as offerings from Microsoft will eat into the company’s lead.

This trend mirrors what Apple has been facing in the smartphone market. Apple’s worldwide smartphone platform market share grew from 14 percent to 18 percent between 2010 and 2011; Android grew from 17 percent to 43 percent in the same amount of time.

To hold its own in the tablet market and in the industry, Apple will have to prove that it can keep up its reputation for innovation. Wednesday’s event was Apple’s first major release since the death of co-founder Steve Jobs in October. While Jobs probably had a hand in developing the new product, many consider this a major test for Cook.

Both of the major products that Apple has unveiled since Jobs stepped down because of his illness have featured minor, evolutionary changes to the company’s innovative products. But Apple has yet to introduce another product with the market-changing power of the iPod, iPhone or iPad.

Not that Apple has to worry about sales. Even though analysts said the iPhone 4S was a disappointment on the innovation front, the handset still went on to become Apple’s fastest-selling device in history , with customers snapping up 4 million devices in its first three days. The company went on to a record-breaking quarter, posting $46 billion in revenue.

Demand for the newest iPhones has soared so high that many Apple customers had to wait because of early supply constraints. Already there are reports from the Asian technology site Digitimes that suppliers indicate that early adopters may have to worry about delays for the latest iPad, as well.

Apple shares fell during the event, down nearly $4 after Cook wrapped at 2:30 p.m. Eastern.