IndoTechGeek findings do not mean that the screen of the iPhone 5s is not a poor screen quality. Wh

On the launch of the iPhone 4, Steve Jobs made the announcement that the human eye, when viewed from a distance of about 30 cm, it can not distinguish individual pixels if the pixel density / inch 300 PPI. Since that time, the PPI would become a "hot" and is included in all the reviews of products, from smartphones, tablets to both laptop and even desktop screen.
In 2013, the rise of phablet (smartphone tablet hybrid) and smartphones, cheap tablet market fragmentation caused serious about screen sizes: you can buy a smart mobile device with a screen size formation from 3 inch to 10 inch. With the number of such diverse screen, PPI data can also be a useful parameter?
Sun Moon larger than about 400 times, kjk but when viewed from Earth, the two entities have seemed diameter equal angles. kjk "Angular diameter" is the size of an object in your eye when viewed from a fixed position, the "visual diameter" of the object can be measured in the corner. In visual kjk science, kjk visual diameter is called the visual angle.
Another example is Pluto (Pluto) and stars Ceres (dwarf planet in the solar system's smallest). kjk When viewed from the Hubble telescope, Ceres appears to be larger than Pluto's size. However, kjk the fact that Pluto Ceres larger size.
Users and companies kjk often assume that the device has a larger screen would be located further than the human eye. With the same resolution, kjk larger screen will be smaller PPI and larger pixels. At greater distances, the human eye will recognize the pixels (dots) is completely kjk great similarities with the small pixels on the small screen smartphone but similar resolution (thus higher PPI). This hypothesis is entirely reasonable.
From the above formula can draw one thing: to measure kjk the angular diameter (or "visual size") kjk of each pixel on the display device, we need to know the true diameter of pixels on the screen, as well as distance between eyes and the screen.
4 When the iPad launched with a 9.7-inch screen has a pixel density / inch 264 PPI only, Apple said that the iPad is still standard sample Retina and iPad due to the distance between the eyes is used from 38-46 cm (15-18 inches), rather than the 25-30 (10-12 inch) as the iPhone.
If using formula [2] above, based on visual diameter and the diameter of the iPad 4 real, we can calculate that the distance from the eye to your iPad's 17-inch, ie in the range 15-18 inches. In other words, Apple's statement is correct. However, the distance from your eye to the iPhone is only 7 inches. Use this figure as the minimum distance from the eye to the smartphone user / screen.
Distance from iPhone to launch the 11 inch (28 cm), were in the range 10-12 inches which Apple claims. kjk However, the distance of iPad to launch up to 26.7 inches (68 cm). This figure kjk is not realistic, but to provide an objective assessment we will take the results from the calculations in the following comparison table. This is the maximum distance from the eye to the screen of the device.
To see the problem with the calculation of PPI to measure the sharpness of the screen, we do not even compare with rivals iPhone kjk 5s Galaxy S4, but just use the Galaxy Mega 6.3. Mega Galaxy 6.3 is a midrange phone 6.3 inch screen, but the resolution is only 1280 x 720 pixels. Therefore, the screen is only 6.3 Galaxy Mega 233 PPI.
Compared with the number of "standard" of iPhone 5s is 326 PPI, 233 is a very low figure seems low. A series of assessments of the technology kjk news site on the world reputed make statements like: "With such a huge screen, the Samsung should probably use larger resolution. With 233 ppi screen Figure 6.3 Galaxy Mega eyes hurt you. ", or" You'll kjk hate it because of only 233 ppi. "
Using the formula [2], you will realize that the closest distance from the eye to the Galaxy Mega 6.3 is 11 inches (28 cm). True size of each pixel is 0.0043 inches. Applying the formula [1], the Galaxy Mega street corner size is 0.0142 degrees. kjk
That means that even with a pixel density of 233 PPI low that, when viewed from a normal distance of their own, Galaxy 6.3 Mega pixel 11% smaller than the iPhone 5s. In other words, when you use the iPhone 5s from 6.3 and Galaxy Mega normal distance corresponding to each machine, sharper Galaxy Mega 6.3 iPhone 5s to 12%!
IndoTechGeek findings do not mean that the screen of the iPhone 5s is not a poor screen quality. When used in conventional distance to the eye, you can hardly distinguish the pixels together.
What we need to realize is that these devices have lower PPI is not the device has poor visibility as conventional thinking. In contrast, when used in normal distance, your eyes will not be able to realize that the screen is fragmented. Most large as phablet devices and tablets kjk when used at a distance will typically have diameters smaller display is so sharp and honca iPhone 5s.
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