Though Sony’s Tablet S has been known about for months now, today they finally unveiled official specifications for the device. While weight isn’t the spec that everyone jumps at immediately, it’s certainly an important factor for a large 10” tablet. Sony says that their Tablet S is just 595 grams, which makes it the second lightest of the top 12 tablets, right between the Samsung Galaxy Tab 10.1 and the Apple iPad 2 (with the Tab 10.1 being the lightest) – quite impressive considering that the Tablet S design isn’t as thin as many of the other tablets on the market because of it’s interesting folded shape, though it should count itself lucky to be considered a 10″ tablet when the screen is actually only 9.4″. Have a look at how the top 12 ten inch-category tablets compare:

I would love to be able to say that tablets are getting lighter as time goes on, but as you can see, there are four Honeycomb tablets that were released after the first (the Xoom) that are actually heavier (though the Eee Pad Slider sort of has an excuse!).

The Tablet S is only about 1% lighter than the iPad 2, but Sony designed it with that funky shape specifically to make it feel lighter in one hand by grouping the weight on one side and reducing leverage again your hand. I’d be curious to see how much torque the iPad 2 puts on a hand vs. the Tablet S.

Following the official unveiling of the Tablet P and Tablet S (formerly the S1 and S2) at IFA this morning, Sony now has official pricing and release dates available online. Right now you can go to SonyStyle.com and pre-order the Tablet S (the single-screened one) in its 16GB flavor starting at $499 (to match the iPad 2, no doubt), while the 32GB version goes for $599.

Sony is running a promotion through October 1st which will provide you with $100 off of the Tablet S if you’re willing to trade in an old tablet.

On this page you can enter your old tablet’s details and see if Sony considers it valid for the promotion. At the moment, Sony lists the following tablet manufacturers as those which would be valid:

• Apple
• Archos
• Dell
• HP
• Motorola
• Samsung
• Viewsonic

Once you select a brand you need to specify the model, so not every old tablet may work, but it won’t hurt to give it a try if you want to trade up to a newer device.

Pre-ordering reveals that the device will become available on September 16th, a little more than two weeks away. It’s nice to finally see Sony get their tablets to market, but I don’t think they represent the bar the Sony had once set for handheld devices.

The dual-screened Tablet S is not immediately available for pre-order alongside the Tablet P, and the release date has not been indicated on Sony’s site.