Apple kicked off this year’s tablet war Tuesday, unveiling the latest versions of its iPads with an eye on an increasingly competitive marketplace.

The new iPad will be lighter, thinner — the width of a pencil — and has a new name, the iPad Air. Its smaller tablet, the iPad mini, will have a higher-resolution display, faster processor and new colors. Both go on sale in November — just in time for the holiday shopping season.

Apple’s news was met with a dueling announcement from Nokia that it is making its first push in the tablet market with the Lumia 2025, which runs a tablet version of Microsoft’s latest Windows operating system. Microsoft’s updated Surface tablet also went on sale Tuesday.

The cramped day reflected a new reality for Apple: the tablet market it helped shape is suddenly very crowded.

Apple’s iPad is facing some of the same competitive pressures the company has struggled with in the smartphone market. When it introduced the iPad in 2010, the firm was the first to show how tablets could fit into users’ daily lives. It has now sold more than 170 million of them. “I can’t think of another product that’s come so far, so fast,” Apple’s chief executive Tim Cook said at a San Francisco event announcing the upgrades.

Apple reveals a thinner, lighter and more powerful version of their popular iPad. (REUTERS)

But, as happened with the iPhone, competitors are beginning to eat into Apple’s tablet market share.

About 65 percent of tablets ran Apple software in 2011, but that is expected to fall to 47 percent by 2014, when Android’s operating system will be running 49 percent of the tablets on the worldwide market, according to data from Gartner Research.

Early Android tablets undercut Apple on price, but struggled to compete on quality, analysts have said. Now, Apple finds itself playing catchup. For example, the biggest improvement to the iPad mini — the retina screen display — only matches what is already provided on similarly priced tablets offered by Amazon and Google.

“Early examples of competing products were crippled” by an inferior product, said Charles Golvin, an independent technology industry analyst. “Now all these companies have stepped up their game.”

As consumers embrace tablet technology, niche devices also are gaining traction. Samsung, for example, recently introduced a new version of its Galaxy Note tablet, which has a pen for those who like to take notes on their devices. Amazon’s new Kindle Fire HDX is going after readers and shoppers who are devoted to its retail businesses. (Amazon chief executive Jeffrey P. Bezos owns The Washington Post.) And Microsoft, with its Surface line, is interested in people who are looking for tablets to replace their laptop computers.

Apple remains on top of the tablet market with 32 percent of worldwide sales, according to IDC. It is also still not attempting to compete on price. The new iPad mini starts at $399 and the full-size iPad Air at $499. That puts the price of the larger iPad on par with its most direct competitors, while the iPad mini remains a hundred dollars more than similarly sized devices, including Google’s Nexus 7.

Losing ground to competitors is not important to Apple as long as it can expand its web of products, said Carl Howe, a consumer technology analyst for the Yankee Group. If someone with an iPad uses the company’s iPhone and other products, the company is building a deeper relationship, he said.

How the new Apple tablets compare to their predecessors

“Apple doesn’t focus on market share, really — it’s not that concerned about it,” he said. “They’re focused on making cool products that sell a lot, preferably to the profitable part of the market. And if its not, they won’t sell it.”

While the tablets were the clear star of Apple’s announcement, the company also announced upgrades to its laptops and desktops. Its new operating system, OS X Mavericks Mac, will be offered for free starting Tuesday.

“Our competition is confused,” Cook said, while introducing a new version of the company’s MacBook Pro laptop — a thinner and more powerful model that starts at $1,299. Competitors, he said, have tried to make tablets into PCs and PCs into tablet — a not-so-subtle dig at Microsoft.

“We have a very clear direction and a very ambitious goal,” Cook said. “We still believe deeply in this category, and we’re not slowing down in our innovation.”