Without doubt, the most welcomed features of Aperture 2.0 are several new image adjustment features included in the program You can almost close your eyes and point them out because they’re so clearly evident. While I greatly welcome the new Lightroom-like features such as vignetting and vibrancy, when I tried out the little feature called Definition, all I could say was, sweeeet.
We all know that both Aperture and Lightroom basically make adjustments to the entire image when they are applied, but with Aperture 2.0, Apple has included Definition as a way of adding local contrast when adjusting an image. Basically it seems to add more contrast to a Contrast adjustment. While the latter affects the entire image, the Definition adjustment affects more local areas, helping to further get rid of haze in the photo.
You can see the changes when applied, but sometimes using the Loupe tool will help you see the changes even better.
Before Definition adjustment:

After Definition adjustment
When I read that Aperture 2.0 had been released today, I couldn’t resist setting aside responsibilities today so that I could get my hands on the updated version. After spending a couple of hours with 2.0, I can honestly that despite its “over 100 dramatic, new features” there’s little or no learning curve to getting up and running with the updated program.
If you’re avid Apple use, and if you have been using a previous version of Aperture for a while, then you’ll feel right at home with 2.0. However, if you need to know more about the new features, such as setting up your camera for tethered shooting or customizing keyboard shortcuts for Aperture, there’s no better place to look than Apple’s very own resource page of video tutorials.
Rarely have I seen a software program receive such a wealth of audiovisual tutorial support, for free! With these tutorials available on Apple’s site, you can always have access to them as you learn about the new features. While these tutorials may not take the place of a good manual book on the program, they make for a very thorough introduction.