Readability: Nexus 7 vs iPad the 3rd

Love to read? Me too. Sometimes it is a novel, sometimes it is one of those super-thick technical books or downloaded PDF. I got tired of dragging books around, and reading in front of the screen is not very comfortable, so I made a small test to find out which mobile device is best for reading technical literature.

Contenders

I took a bunch of devices with screen of different size, density, and even technology. Our contenders are:

• Samsung Google Nexus S, 4" smartphone with high density screen
• Asus Google Nexus 7", 7" tablet with high density screen
• Toshiba Thrive 10.1" tablet with large screen, but medium density
• iPad 2 9.7" tablet, low density
• iPad 3 9.7" tablet, high, "retina" density
• Kindle DX 9.7" e-reader, medium density

Test

I took three-column PDF magazine, PDF technical book, and three-columns content-heavy web page and checked how each of those look in portrait and landscape orientation. I skipped the web test for Kindle.

To keep the long story short, I made a table with my subjective results. Note the pixel-per-inch (ppi) value for each device; it tells us how densely pixels are packed. If two devices have same resolution, but different screen size, device with smaller screen will have higher ppi. If two devices have same size, but different resolution, device with higher resolution will have higher ppi.

Device		Nexus S	Nexus 7	Toshiba Thrive	iPad 3
Resolution		800x480	1280x800	1280x800	1536x2048
Size		4"	7"	10.1"	9.7"
Density (ppi)		233	216	149	264
Size Qualifier		normal	x-large	x-large	x-large
Density Qualifier		high	tv	medium	high
Magazine	Portrait	-	-	o	++
	Landscape	-	++	++	++
Technical	Portrait	--	-	-	+
	Landscape	-	++	++	++
Web	Portrait	--	-	-	+
	Landscape	-	o	++	++

-- totally unreadable
- letters are too small to be read comfortably
o letters are borderline small or ugly
+ letters are readable, but could be small for some people
++ nice, big, readable letters

I ommited iPad 2 because it has results similar to Toshiba Thrive. iPad was slightly worse, but not enough to give it lower grade than to Toshiba.

In portrait orientation, none of the test documents were readable on any of the devices except iPad 3. Its size and resolution really shows here. Magazine was readable on Toshiba Thrive, but letters were quite ugly.

Landscape orientation gave screens some room to breathe. With the exception of smartphone, where text was too small, and web page on Nexus 7, where text was barely readable, all other cases were quite good. There is a funny problem with Acrobat reader, though: on large screens letters are too big and Reader doesn't allow to zoom out (zooming in is always possible).

Other findings, or why e-paper still matters

All devices except Kindle have glossy screens. In areas where bright light comes from above, like outdoors or typical office environment, it is quite distracting. Screens are good at showing vivid colors in games and movies, but they are barely suitable for reading.

All ~10" devices except Kindle are too heavy to be held single-handedly, and even Kindle is too heavy for prolonged use. Maybe 9" devices could serve the purpose better?

User interfaces on tablets are not suitable for single-handed use. While navigating through document is possible, menus are out of reach.

PDF on small screens doesn't work. Every decent mobile browser can zoom in on text column. HTML file describes structure of the document; browser can use this information to intelligently zoom or reformat document. PDF file describes location of different page elements, without knowing anything about structure. PDF reader doesn't have right information to adjust document for small screen. Although many readers have re-flow function, it doesn't work on complex documents.

Conclusion

It is not size that counts, but rather density. Go for high ppi first (>200 ppi), and then for the size if you can bare both weight and price.

Smartphones, even big ones, are horrible for reading PDFs. Stick with apps, mobile versions of sites, and e-books in mobile formats, like Mobipocket or ePUB. Hopefully PDF will go Flash way and become obsolete.

For landscape reading, get 7" high-res tablet. 10" low resolution tablet is not better, and it is heavier, bulkier and more expensive. Consider it if you have vision problems and you can get it cheaply.

By cheaply, I mean much cheaper than iPad 3. It is almost perfect reading device. Letters are crisp and readable even for densely packed content in portrait view. I hope that new generation of 10" Android tablets with full HD screens will reduce the price without sacrificing quality.

While e-ink reader cannot compete with tablets in terms of resolution, it still outperforms them in bright light readability and long battery life.

Special thanks to people, who provided equipment for testing (in alphabetical order): +Daniel von Elf, +Goran Bokun, +Igor Ragic and +Robert Saric .


Photo credit: Željko Trogrlić