Going to get straight to the point with this one: FiftyThree's Pencil Bluetooth Stylus isn't worth $50. It may be one of the best styli you can buy to use on an iPad--or at least the most comfortable--but ultimately disappoints as a viable alternative to writing or sketching with an actual pen or pencil on a sheet of paper. The problem isn't that Pencil fails to achieve what its creators wanted it to do, but that it, along with every other capacitive stylus for the iPad, is trying to address an unsolvable problem. The capacitive touchscreen of the iPad--and corresponding iOS finger-detection software--simply was not made to work well with a stylus.
If you want to buy a stylus to draw or write longhand on your iPad, you have two basic options. The first is a "dumb" stylus that's essentially a pen with a rubber tip (or nib) that activates the iPad's capacitive sensors, just like your fingers. Studio Neat's Cosmonaut is a good example of this kind of stylus, but you can find alternatives in all shapes and sizes, and often at very lost cost. In this category, what matters are the ergonomics of the stylus body and the rigidity of the nib--which determines how much "feedback" you get when pressing the stylus against the screen. Many artists stand by these simple styli and are able to doodle and actually work with them.
The other category of iPad stylus has electronics to communicate with the tablet to better simulate the pen and paper experience. These typically pair with the iPad over Bluetooth, using that connection to enable features like palm rejection, pressure sensitivity, different "brushes", and even erasing. But in order for these smarter styli to work properly, they have to be used in apps that recognize their capabilities. That's how Pencil works.
FiftyThree (the team that worked on Microsoft's canned Courier tablet project) created Pencil to work in concert with its Paper app. We've talked about Paper before, and not much has changed since its release last year. It's still an elegant drawing app that's really simple and fun to use, with either a stylus or finger. Five different virtual brushes are available (one is free, the others are $2 each), and Paper's innovation is that it uses the speed of your brush stroke to determine the width of the line drawn. The idea is that the faster you move your finger across the screen, the less weight you're theoretically applying to the stroke; pressure is extrapolated from speed.
That's ostensibly the reason the Pencil stylus doesn't have pressure sensitivity like other Bluetooth connected styli like Pogo's Connect or Wacom's Intuos Creative Stylus. For some digital artists, that's a deal-breaker, since Pencil won't work as well on pressure sensitivity-enabled apps like Autodesk Sketchbook Pro and Adobe Photoshop Touch. But that's not the reason I was disappointed by Pencil. The problem is latency.
In testing Pencil, I put it in the hands of two people who actually draw. Joey, our producer, makes great doodles with pen and paper, and I had him try sketching with Pencil on the iPad Air. I also gave Pencil to my dad, who is a trained watercolor artist, to see how he would fare on a digital canvas. Both were able to quickly get accustomed to the nuances of using the Pencil stylus on the iPad, such as how palm rejection worked (disabling multi-touch gestures is necessary) and the eraser nib. The eraser was the best part of the experience, they told me--being able to simple flip Pencil around like a real pencil and scrub away mistakes or other details. That part worked flawlessly. They also both said that Pencil's unique rectangular shape (akin to a carpenter's pencil) was comfortable to grip. I personally found it a more comfortable grip than the Cosmonaut, and the magnets embedded in the $60 Walnut version of Pencil were useful for snapping it to my iPad Air's Smart Cover.
But both also had the same complaints that I did with Pencil--that the nib is too soft for accurate drawing, and that there's too much lag between when you press the Pencil to the screen and when your line appears. These issues are related. Inside Pencil's rubber tip is a metal frame that acts as the actual sensor for Pencil. It's recessed several millimeters under the tip, and it's not until you actually press this metal tip to the iPad surface that Pencil relays to Paper your intention to draw. The fact that Pencil has to send a signal over Bluetooth to Paper to indicate contact between the stylus and the screen creates just enough latency to make drawing feel disconnected and distant. The immediacy of real pen/pencil to paper is extremely important, especially for artists who sketch fast. Bluetooth styli can't accurately simulate that experience, and artists have to compensate by either sketching slower or being more cautious about their strokes. It's an unfortunate distraction that isn't outweighed by the benefits of digital sketching.
The soft nib problem is something shared by all other iPad styli, smart or not. All capacitive styli have to be designed with rounded tips, because they're effectively simulating a finger. That's because the iPad was designed for finger use, and its touch algorithms are programmed to extrapolate accuracy based on contact from a rounded finger, not a sharp point. Everything that iPad stylus makers do to simulate the feel of using a pen or pencil is a hack to get around the iPad's capacitive design and inherent limitations. That's why, thus far, they've all be inadequate--all of these innovations and high technology put in these styli are done to make the iPad something good at a task it was never designed to do (and something Apple doesn't necessarily want the iPad to be good at doing). Digitizer-enabled tablet like ones made by Wacom or Microsoft's Surface Pro have an inherent advantage over the iPad as a digital drawing canvas, but the iPad's sheer market share and reach makes capacitive styli for iOS the more lucrative business. This bootstrapping of technologies to the capacitive stylus to meet user demand has just resulted in so-so solutions at silly prices.