Quick quiz for those planning their first visit to Silicon Valley. You’re at a networking event (Valley equivalent of a cocktail party), and you overhear some people talking about “real estate problems”. They are most likely referring to:
A. Whether or not the San Francisco Board of Supes will approve a SOMA warehouse conversion to office space for 10 social media startups.
B. The fact that, even after the housing bust, a tarpaper-roof shack in Cupertino is still going for more than half a mill.
C. How much interaction you can cram onto a touch screen measuring three-and-a-half inches on the diagonal.
D. Any and all of the above.
Hang around here long enough, and eventually, “D” becomes the right answer. But “C” raises some interesting points. For the same reasons that a fish has trouble understanding the concept of “wet”, we often take for granted, and have little insight into, the impact of the design of humans on things humans design.
In an article by AP’s Peter Svensson, there’s a report of a peculiar disconnect from a company that we’ve come to associate with product winners: Apple Computer. Svensson quotes the late Steve Jobs as dismissive of smaller tablet computers’ “… clear limits of how close you can physically place elements on a touch screen before users cannot reliably tap, flick or pinch them. This is one of the key reasons we think the 10-inch screen size is the minimum…”
If you responded “Huh?”, you may not appreciate the brilliance of Mr. Jobs, but at least you’ll agree with me and Peter Svensson, who closes the article with: “Jobs failed to mention Apple’s success developing apps that use taps, flicks and pinches on the iPhone, with its 3.5-inch screen.”
Although I’m aware of the physical limits on the input side, I always thought that the output-side issues provided the stronger argument against increasingly small devices. Years ago I read somewhere that going to the movies to see something on the “big screen” was simply a psychological illusion: someone calculated the percent of your field of vision taken up by a movie theater screen and a home television, and found that, contrary to all intuition, the TV took up more simply because it’s so much closer.
I didn’t believe that article then, and I don’t actually believe it now…but I will, if I see the math. Below, the results of my own experiments.
I’ve always been annoyed by new product announcements showing smart phones with sports fans glued to events streaming live to their tiny display areas. How close would you have to get to even figure out what teams were playing, let alone appreciate the plays?
The answers will surprise you. In the table below, all measurements of length are in inches (standard in the US, for diagonal measurement of screen sizes); the other numbers are ratios. The other key to understanding this table is that the input numbers are in blue; derived numbers in red.
| Device | Diagonal | Viewing Distance | Ratio |
| Television |
26 |
168 |
6.5 |
| Sony VAIO (laptop) |
15 |
22 |
1.5 |
| iPhone (TV equivalent) |
3.5 |
22.6 |
6.5 |
| iPhone (laptop equivalent) |
3.5 |
5.1 |
1.5 |
No amazement in the first two lines. I sometimes watch television on the laptop, sometimes on the living room TV. Both are very acceptable, however, per my expectations, the laptop takes up much more of my field of vision.
However, the shocker is in line 3, which proves: an iPhone, the same distance from my eyes as my laptop screen, will cover the same amount of my field of vision as the living room TV!
Counterintuitive? Yes. Reproduceable? Like all good science, absolutely; all you need is a tape measure. Will your results be exactly the same? Probably not, because there will be some variation in both viewing distance and device screen size. But, things will come out in the same ballpark.
So, Steve Jobs had a blind spot on the input side, and I’ve completely misfired on the output end. I can hear our readers asking themselves: “If this issue throws off Steve Jobs and Greg Marus, what hope is there for the rest of us?”
Stay tuned for the next post.
–Greg Marus












































