Usability for anything, anywhere, anytime.

Amazon Kindle Fire

January 8th, 2012, Posted by Mark Sloan

The Kindle Fire (or Fire for this article) entered the “tablet” market this Fall sporting a tiny package and the full Amazon suite of media products behind it (books, movies, music, apps). With Amazon’s own application store, the Fire has access to Android applications, but not the full suite of the Android Marketplace. Other sites such as Engadget», The Verge», Anandtech», and Arstechnica» are the place to go for detailed analysis of specs and features. They’ve done a great job and there is little to add there. What this review will do is examine the Kindle from a usability perspective, specifically, how easy it is to use the interface and then how easy it is to read typical content. The short answer is that this feels like a new category of device, not a full-fledged tablet.

Starting Up

The first thing that surprised me was I did not know how to turn it on. In fact, I handed the device to five different people and only one of them found the power button in less than five seconds. Then, figuring out how to unlock the device was tricky as well as Amazon uses a subtle yellow triangle pointing to the left to hint at how to unlock it. Part of this is due to patents, but there are other clever designs out there that seem more obvious. Once the device is unlocked, more confusion sets in as the overall mental model seems to be lacking.

Mental Model

The iOS model is fairly simple. The launcher has pages of apps (with folders) that users swipe sideways to access and then launch applications. The applications launch in an animation that reinforces the idea that they open “on top” of the launcher plane. When closed, they shrink back into that same plane. Other parts of the UI such as the lock screen and notifications (as in Android) help reinforce the mental model of planes. The Fire simply is not as refined and the transition animations and UI elements create a bit of confusion instead of helping solidify where you are in the interface, where you are going, and how things are related to one another. The main issues are that the system begins with an interface with large carousel which is unlabeled, with a shelf system below that which is also unlabeled, with what looks like tabs across the top of the screen.

Size Affects Usability

The size is quite smaller than an iPad or the larger Android tablets from Motorola or Samsung. While this appears to be a great form factor for reading standard Kindle formatted books, the diminutive size has limitations for standard applications such as web browsing, email, and reading magazines or newspapers. Part of the fault lies in the size of the screen. At 7 inches, even with 1024×600 pixels providing 169 ppi (pixels per inch), it simply does not provide much room for text to be large enough to be readable. The tradeoff then is less content per screen view for lighter weight, great portability and $199. Jakob Nielsen’s Alertbox» has a review of usability based on target sizes and the results were not favorable. In fact, much of what they discovered is that for the Kindle Fire, full scaled websites do not render well at that smaller size.

What we found when looking at websites at default size (partially zoomed), full size, Kindle Books, Magazines, and email is that only Kindle books (at default size) were easily readable and the zoomed default of the New York Times website was just barely readable, even though it has a high resolution screen. There are diminishing returns on resolution density when it comes to the human eye, and at that point, the physical size of the type or object is the limiting factor. In fact, size is a dissociative retinal variable, meaning it affects your ability to see other variables such as character shapes or letters properly.

From left to right: website default, website full page, Kindle book default, magazine, email. Even zoomed out, the size of text for books is dramatically larger than for the other applications.

From left to right: website default, website full page, Kindle book default, magazine, email. Even zoomed out, the size of text for books is dramatically larger than for the other applications.

From left to right: website default, website full page, Kindle book default, magazine, email. 2mm appears to be the minimal readable height, but testing for impaired vision would likely prove even this too small. The default for the iPad 2 on the same website was about 1.9mm.

From left to right: website default, website full page, Kindle book default, magazine, email. 2mm appears to be the minimal readable height, but testing for impaired vision would likely prove even this too small. The default for the iPad 2 on the same website was about 1.9mm.

The quality of the screens themselves are fairly close, though the site Displaymate» goes into a lot of detail about this if you want to learn more, they compare the Fire to the Nook and iPad 2 because they all use IPS technology. Given that Kindles have traditionally trumpeted their lack of reflections and ability to read in daylight, the Fire was surprisingly reflective (we experienced these issues when photographing and filming it) and only average in brightness. We do not have the same depth of tools, so we simply used a cheap USB microscope and zoomed in on each to see how they looked. Up close, at about 400x magnification, you can see a little difference in size and shape, but it was fun to see the difference of the 169ppi of the Fire versus the 132ppi of the iPad2.

Screens at approximately 400x magnification, left Fire, right iPad2

Screens at approximately 400x magnification, left Fire, right iPad2

Tablet or something else?

The consequence of trading portability for size is that now when a user wants to read a news website, or a magazine, they either have to switch to a text based mode (for Kindle magazines), losing the magazine experience, or they must zoom in and out more than they would with a larger screen. This may be a fine trade off for some, but the value proposition is $199 for this tablet, or $269 or more for a larger tablet with a camera, SD slot, full Android Marketplace, etc. And this is the crux of the user experience for such smaller tablets, is the size so limiting that they really are no longer tablets? Amazon has definitely positioned the Fire as more of a consumption device than a full fledged tablet. But this is certainly not a phone sized device. So where does this leave us in terms of defining what the device is? For lack of a better term, maybe we should call these mini-tablets.

This could be a similar situation to how the Mac mini lacks some of the features of larger Macs, but are still valuable and worthy of a place in many homes and businesses. What really struck me when the original iPad came out was the idea of a durable, high-quality alternative to a laptop for kids at $499. The Fire is not that, but for a lot of kids or people that have laptops or desktop computers already, this price point and feature set strikes me as a very large potential market. I do think that screen size prevents it from doing a lot of Tablet type tasks well though, so there is room and a purpose for mini-tablets, tablets, and laptops. A big reason is that the scale of feature set and screen size fits nicely with the increase in prices. What will be interesting is to see if the Fire eats into iPod touch and other product sales at the high end, leaving more room for the cheaper nano and shuffle devices.

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