According to the Lensbabies Web site, inventor Craig Strong started the company in an effort to create a digital equivalent for his trusty Holga film camera. Now, in the lens' third iteration, he has created something infinitely more useful and, in my opinion, more fun than a Holga, and more akin to a tilt-shift lens. Rather accurately, Strong calls the Lensbaby a "selective focus" SLR lens. In practice this means that by moving the front lens element, which is mounted on a plastic bellows, you can blur portions of the image while keeping another area in focus.
The system's concept has remained the same since the first Lensbaby, now called the Original Lensbaby, which does not have a locking mechanism or a focus ring; both the focus and the selective focus effect are controlled by moving the front element on the bellows. Its second generation, aka the Lensbaby 2.0, offers higher-grade optical elements and extends the maximum aperture to f/2.0, compared to the original's maximum aperture of f/2.8. Both the original and the Lensbaby 2.0 offer aperture discs to let you stop the lens down to f/2.8, f/4, f/5.6, or f/8. However, the Lensbaby 2.0's aperture discs are easier to use because they rest atop magnetic points instead of being held in place by rubber gaskets, as are the original's.
The Lensbaby 3G is a leap forward for the system. By incorporating three screws that act as locking rails, you can lock the front element into place by pressing a small button on the side of the ring that's on the front of the bellows. That means you can precisely position the focusing sweet spot and keep it there while you pay attention to operating the camera's controls. Plus, since the locking rails are screws, you can also fine tune the distortion by turning the screws so that the front element moves slowly along the threads. With previous versions, you have to try to hold the front element where you want it while you press the shutter button. If you want to quickly change ISO or white balance on your camera, you have to start from scratch again to find your sweet spot and focus.
In addition to the locking rails, the Lensbaby 3G also has a focus ring, though it has a pretty small turning radius and is rather loose compared to most SLR lenses, so it's easy to overadjust, especially if you're not used to it. Plus, the Lensbaby 3G offers eight possible apertures, from f/2.0 to f/22, compared to the four and five possible apertures, respectively, for the Original Lensbaby and the Lensbaby 2.0, both of which offered a minimum of f/8. Like the Lensbaby 2.0, the Lensbaby 3G's aperture discs mount magnetically. While this is more convenient than the rubber gaskets on the Original Lensbaby, changing apertures still requires switching a disc that sits in front of the front lens element. If Mr. Strong could figure out a cost-effective way to build in an aperture blade mechanism with an aperture-ring control, such as the ones found on some Nikon lenses and all lenses that predate electronic aperture controls, then he'd be a major step closer to creating the ultimate, low-cost, selective focus SLR lens.
Of course, as it stands he's pretty close. Compared with the first two generations, the Lensbaby 3G is a dream to operate. The locking mechanism and focus ring make the Lensbaby experience less of crapshoot, though you can still mimic the classic experience if you crave the uncertainty of the first two generations. Since the company is obviously rather small, Lensbabies can be tough to find at some online retailers, but you can order the Lensbaby 3G directly from the Lensbabies online store. If you're not used to the cost associated with SLR lenses, or even if you are, you may balk at the $270 price tag in the company's online store, but given its complex design, its quality construction, and the addictively fun experience of using one, it does seem worth the cost.