The best iPad apps this week include a couple of the photographic tools, including one that will beef up your skills and another that makes Instagram viewing easier. Also joining the party is a new and improved—and free—version of a popular bookmarking tool.

Iris App: Though Instagram hasn't made its way to the iPad yet, you can still look at all your photos on Apple's tablet. Iris lets you do just about everything you do on for-real Instagram, save for adding new pictures, and it's a pretty good-looking app. $1.99

Scott Kelby's Lighting Recipes: What's the best way to photograph someone in direct sunlight? Or what about taking a picture indoors? This app gives you all kinds of tips and tricks. In 13 video lessons, Kelby tells how to achieve 20 different shots taken in various settings, from wedding portraits to studio shots. Free

Pocket:Read It Later has made its return as Pocket, a sleek, completely redesigned bookmarking app that ensures you'll never miss an interesting article, clip, or picture. This new version has a totally new look and has added support for pictures and videos. Free

The Fourth Dimension:If you're not a mathematician, it's hard to understand the fourth dimension. However, this app caters to those who don't think in numbers, attempting to explain the 4D world and tesseracts through photos and videos in an interactive environment. And it just might blow your mind. $2.99