After selling 100 million iPad tablets since March 2010, and seeing competitors such as Amazon, Google and Barnes & Noble follow with similar but smaller tablets, Apple jumped into the almost pocket-size tablet market Tuesday.

The iPad Mini, as expected, has a slightly larger screen than competitors — 7.9-inch vs. 7-inch for the Kindle Fire and the Google Nexus 7 — and a larger price — $329. Amazon and Google both have $199 versions of the Kindle Fire and Nexus tablets.

“The whole competitive landscape of tablets just got turned upside down,” said Gene Munster, an analyst with Piper Jaffray.

Munster predicts the Mini will appeal to more price-sensitive consumers, and forecasts that Apple will sell 5 million by the end of the year.

Apple also introduced a new version of the 9.8-inch standard iPad Tuesday, with a faster processor and improved HD video camera. It replaces the third-generation iPad, which went on sale in the spring, and starts at $499. The new iPads can be pre-ordered starting Friday, and go on sale Nov. 2.

Apple shares fell $20.67 Tuesday to close at $613.36.

Meanwhile, Microsoft will show its answer to the iPad — the Windows Surface tablet — Thursday in New York at the launch party for the Windows 8 operating system upgrade. The $499 tablet-meets-computer runs on Windows 8, and has a 10-inch screen. And on Monday, Google introduces a new Android tablet in New York.

The iPad Mini is slightly larger but wider than other small tablets. At its presentation here, Apple touted that the video and images would look better due to the extra real estate.

While Apple has a commanding 68% market share of tablets, according to tech research firm IDC, it has been losing ground in the corporate market to smaller tablets, says Ted Schadler, an analyst for Forrester Research.

“Apple needed to respond to this consumer and employee demand for smaller tablets,” he says.

Introducing smaller versions of its products isn’t new for Apple. The company has successfully launched smaller versions of its iPod music player (the Nano and Mini) and computers (the Mac Mini.)

On Tuesday, an ultra-thin iMac desktop computer, without a DVD drive, that starts at $1,299, and a 13-inch $1,699 version of the MacBook Pro with ultra-sharp “Retina” display both went on sale.

iPad mini: 10 things you need to know

1. The iPad mini release date is Nov. 2

We expected the iPad mini to ship in plenty of time for Christmas, and Apple didn’t disappoint: the Wi-Fi model will start shipping for delivery on the Nov.2, with the LTE version coming along a few weeks later in late November. Apple will start accepting iPad mini orders on the Oct. 26.

2. The iPad mini price is $329

Prices are slightly higher than anticipated, but it’s still the cheapest iPad yet: the Wi-Fi version of the iPad mini starts at $329(GB£269, AU$369) for the 16GB model, rising to $429 (GB£349, AU$479) for the 32GB model and $659(GB£429,AU$589) for the 64GB. As you’d expect the mobile broadband version is more expensive: it’s $459(GB£369,AU$509) for 16GB, $559(£449,AU$619) for 32GB and $659(£529,AU$729) for 64GB.

3. The iPad mini screen size is 7.9 inches

Apple clearly believes that seven inches is a little too small for a tablet: the iPad mini has a 7.9-inch backlit IPS display running at a resolution of 1024×768. That gives it the same resolution as an iPad 2, so while it isn’t a retina display the smaller screen means it should look much sharper than the iPad 2. The overall dimensions of the iPad mini are 200mm high, 134.7mm wide and 7.2mm deep, and the entire package weighs a titchy 308g.

By keeping the same screen resolution as the iPad 2, the iPad mini will be able to run iPad apps without any horrible rescaling or black bars – and as Phil Schiller showed far more often than was strictly necessary, it delivers significantly more screen real estate than a typical seven-inch device.

4. The iPad mini specifications are similar to the iPad 2

While the fourth generation iPad gets an A6X processor, the iPad mini sports something a bit older: an A5, the same dual-core processor you’ll find in the iPad 2 and iPhone 4S. That isn’t the very latest Apple processor, but as we know from our iPad 2 it’s more than capable of handling even the most demanding apps – and it doesn’t need an enormous battery to keep it running.

5. The iPad mini is black, but also white

Rumours of multi-coloured iPad minis proved incorrect: as with its big brother, the iPad mini comes in a choice of white or black, although while the normal iPad has a plain metal back the iPad mini has iPhone 5-style silver and black back covers. Perhaps we’ll see multi-coloured cases in next year’s inevitable second-gen model.

6. The iPad mini does 4G LTE

Like the iPhone 5, the iPad mini has different versions for different LTE bands: model A1455 will do LTE bands 1, 3, 5, 13 and 25, and model A1454 will work on LTE bands 4 and 7. That means for U.K. users, its model A1455: band 3 is the 1800MHz frequency used by Everything Everywhere’s 4G LTE network.

7. You can use it as a camera without embarrassment

The iPad mini has a front-facing 1.2MP camera for FaceTime calls and a 5MP rear-facing camera for still shooting and 1080p HD video recording, and that smaller case won’t look as silly when you try and shoot photos with it. There’s no flash but the sensor has backside illumination and an f/2.4 aperture for low-light shooting.

8. The iPad mini wireless is dual-band

Both the Wi-Fi and Wi-Fi+Cellular versions of the iPad mini benefit from dual-band Wi-Fi, with support for 802.11a/b/g wireless and 802.11n on both the 2.4GHz and 5GHz frequency bands. All iPad minis also get Bluetooth 4.0 for low-power connections to accessories and peripherals.

9. The iPad mini battery is good for all-day use

One of the best things about the iPad is its all-day battery life, and the iPad mini touts 10 hours of battery life from its 16.3-watt-hour lithium polymer battery. On mobile data, Apple reckons you’ll get nine hours of web browsing.

10. The iPad mini has a lightning connector

Not a big surprise, we know, but the iPad mini has the same tiny Lightning connector as the iPhone 5 so you’ll need an adapter if your existing accessories expect a Dock connector.