Display technology is making giant strides. Thinner, bigger, higher resolution, better color and contrast. And better value for money too. Inspired by Ted Gould’s blog’s entry, here a few thoughts about the consequences for panorama making and usability.
1. The Human Eye
The human eye has an average angular resolution of about 0.02°-0.03°. If we were surrounded by a circular display we could theoretically distinguish 18,000 pixels on a horizontal line. The pixel size would depend on the circumference of the line. If that circumference had a radius of 60cm/2ft (typical desktop display distance) the corresponding pixel pitch would be 0.2mm or 122 pixel per inch. At 30cm/1ft (typical notebook display distance) it would be 0.1mm or 244 ppi.
Since 98% of the audience does not zoom on panoramas, 18,000 pixels is enough horizontal resolution for a full spherical panorama in most cases.
2. Aspect Ratio
The absolute dominance of the 4:3 aspect ratio, inherited from last century’s TV, is over. TV is finally switching to 16:9. Unlike ten years ago, this time it’s real.
5:4, introduced for high end displays in the CRT era, has a spike of popularity as the native resolution of the early 17″ and 19″ LCD display. It will be superseded by 16:10.
Widescreen is here to stay, but is not alone. Ultramobile PC (UMPC) and cell phones add variety, for example the 4:3 QVGA of Nokia’s N95 and Apple’s iPhone.
Last but not least, dual displays: below an example of 2×19″, with a combined aspect ratio of 10:4.
We can no longer assume a specific aspect ratio, and this influences the choice of initial zoom.
3. Display Resolution of the future
1024×768 and 1280×1024 are still dominant, but their share is falling rapidly. Conventional wisdom is that a 6000 pixels wide equirectangular is enough for a full screen panorama on a 1024×768 display.
HDTV and Blu Ray Disks are setting a new standard. 1920×1080 pixels is here to stay in the living room. Discerning media consumers that want to protect their investment will not settle for less. That’s 1920×1200 on the desktop and these displays have recently reached a pricing sweet spot. I expect their market share to grow dramatically. To satisfy the quality of such display, at least 12000 pixels wide equirectangular are recommended.
But the distribution is becoming wider. In the past ten years more than 80% of displays were between 800 and 1280 pixels wide. Now the distribution is stretched upwards by Full HD and downwards by UMPCs with 1024×600 and 800×480; and the cell phones with 480×320. And somewhere in between are notebooks; 1280×800 is currently the most popular notebook display resolution.
We must cater down sampled versions for those displays.
At least one things stays constant: Panoramas are better viewed full screen on large displays.
Optimal display size depends primarily on user preference and on the application. There is no one-size-fits-all solution. For the living room,even at 60″+ bigger is still better. For cell phones and UMPC the opposite is true. For desktops there is a comfortable compromise between size and viewing distance; and for notebooks the main trade off is mobility.
There is a fixed relationship between the field of view of the eye, the viewing distance and optimal display size. At about 10cm/4″ a display of 14″ will cover more than what the eye can see. On the laps, at 30cm/1ft, it will be equivalent to a 62″ panel in an average living room setting.
The different sizes and display resolutions have a consequence on control: they change size. What may looks right on an UMPC is a microscopic stamp on a Full HD display and what looks right on the Full HD display covers so much precious screen real estate that the actual content being controlled is hopelessly hidden. Adjust control size to display size and give the user an easy way to switch between the different control sizes.
To keep up with the evolution in display technology:
- upgrade to a camera kit that can produce equirectangulars of 12000 to 18000 px width
- adapt initial zoom to detected aspect ratio
- adapt resolution to screen size
- adapt controls size to display resolution and let the user override the adjustment
- keep displaying panoramas in full screen
- one-size-fits-all no longer works