When you first download Word Lens, the app's functionality is decidedly more limited than that: Instead of translating words, it can simply reverse their letters, or make them disappear. It's as if Quest Visual knew its app's feature set was so unbelievable that the company decided to give Word Lens away loaded only with the parlor trick features, so that you could experience first-hand its seemingly fantastic ability to work as advertised. With an in-app purchase--currently limited to a $5 Spanish-to-English mode and a $5 English-to-Spanish mode--you can start using the app for more useful purposes. (Each in-app upgrade is set to double in price come January 1, 2011.)

In practice, unless you have an exceptionally steady hand, Word Lens is slightly less magical than one might hope. It's true, you really can hold up your iPhone 3GS, iPhone 4, or fourth-generation iPod touch to clear text and watch as the words are translated, near instantly, and superimposed slickly on the screen. In my testing, however, the app didn't respond well to even slight hand movement; the translations would jump and change continuously, since my hand couldn't remain perfectly still. The app would momentarily not recognize a string of letters as a word, and then translate it again, and then repeat the cycle. Most of the time, though, that wasn't a huge deal: you saw enough to get a sense of what you were reading.

The app sports a pause button, which is especially useful when you're attempting to translate larger chunks of text. Wait till the on-screen translations are at their least jumpy and pause, and then you can read through them without attempting to remain frozen in place.

If you're using an iPhone 4, you can take advantage of virtual buttons for zooming in or toggling the flash.

Perhaps Word Lens's biggest limitation is its inability to work with more fanciful text. The more playful or decorative the font, the less likely the app will be able to interpret the letters. Word Lens works great with road signs, printed menus, and the like, but can't handle text that's handwritten or Comic Sans-esque. When you encounter words that Word Lens can't identify visually, you can use the app's far less flashy typing-based translation--tap in a word, and Word Lens provides translations.