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There is much information on the internet about AMOLED and LCD technology listing the advantages and disadvantages of them. It is easy enough to understand how they work and how one may be better than the other in theory. But to figure out what this all means in everyday use means that you need to buy two of them and compare them side by side. For this reason I have purchased two of the best displays in the mobile phone world:
AMOLED – Samsung Omnia 7
LCD – Apple iPhone 4
So which one is better for everyday use? Lets find out.
I set up my two phones and my camera in the configuration shown in the diagrams. The camera was held at an angle of 20 degrees to the normal as this represents a typical position to hold the phone in normal use. The phones were placed next to each other side by side and the test images displayed simultaneously. This setup eliminated any error from changes in lighting and ensured that the same exposure settings were used to capture the image on both devices. Camera used is a SONY DSC-V3.
Both phones are wearing screen protectors again to mimic ‘normal’use.
Images were used from http://www.lagom.nl/lcd-test/
who carry an array of very useful images for display testing.
There are limitations to this type of testing. Obviously this is as much a test of the capabilities of my camera and the monitor that you are using right now to read this as the displays themselves. The reduced dynamic rage of a camera compared to the human eye means that the images that you see here are not the way I saw them first hand. But alas I have no more accurate way of testing the displays and at least because the pictures are taken simultaneously, side by side by the same camera, some amount of comparison is possible.
With the help of the test images, the difference in display capability can be recorded quantitatively instead of relying on the pictures themselves. This eliminates variability caused by the camera but still leaves the results subject to my eyesight.
To further help minimise variability, I first left both phones on auto brightness and set the manual controls on the camera to ISO 100, shutter speed 2 seconds and aperture of f-8. However I soon had to manually ramp up the brightness on the iPhone display to compare with that of the Omnia. I then resorted to setting the camera on automatic as some images were either too dark or overblown depending on the test image. Although the camera would have used different settings for each frame, comparisons within a frame are still valid.
The first test image examined the different reproduction of colours. The Omnia 7 display was able to give much more saturated colours than the iPhone. The colours on the Omnia 7 looked much brighter and had a higher contrast. Whether this is more realistic or not is another question. The iPhone display suffered from its low contrast ratio with colours appearing more washed out. In addition, the constant light leakage from the supposedly black background made the colours even less impressive. Nevertheless, all colour bars were visible on both displays. Winner = AMOLED
This is the same image viewed in direct sunlight. The effect of the harsh direct lighting can be seen in the highlighting of the fingerprints on both displays. Because of the high ambient lighting, the iPhone
suffered less from it’s lower contrast ratio as the background on neither handset appeared to be completely black. The colours however seem equally saturated on both displays. On the iPhone the colours were visible up to the 10 from the bottom but on the Omnia, they were visible up to 6 from the bottom.
Winner = AMOLED
This image tests the display’s capabilities of displaying a continuous progression of intensities without banding. Both displays handled this well although there were slight differences. The Omnia 7 displays whites very well while white on the iPhone had a slightly yellow tinge to it. Again the visible background on the iPhone made it less attractive. Winner = AMOLED
The same image displayed in the sunlight tells the same story as the colour bands earlier. There is almost nothing between the displays in direct sunlight. On both handsets the white bands fade to grey and not black. Winner = Tie.
This image tests how the displays handle blacks very close to total blackness. Out of 20 squares, the iPhone distinguished the brightest 13 from the background while the Omnia 7 was able to distinguish 22. Winner = AMOLED.
In the sunlight, the first 6 shades were distinguisible on the iPhone but on the Omnia 7 only the first 5 could be clearly seen. Winner = LCD.
This image tests the capability if the display to display the brightest whites. Of 12 squares, the iPhone was able to display 11 of them clearly while the Omnia 7 could only manage the first 7. Winner = LCD.
In the sunlight, the iPhone still managed to display 11 of the squares while the number of squares distinguishable on the Omnia 7 dropped to 6. Winner = LCD.
All of the pictures shown above were taken with the camera on automatic settings. However I decided to switch to manual settings and take one picture in the dark to give a better idea of how the displays appeared to the eye:
This image gives an idea of how the displays compare in real life use. The difference really is that striking. Winner = AMOLED.
The first thing to get out of the way is how stunning the AMOLED display is compared to the LCD when used indoors. The colours are very saturated, bright and vibrant. This coupled with the high contrast levels mean that the AMOLED display is immediately superior.
Before starting to do the tests on the two types of display I was certain that the results would be along the lines of the AMOLED being better indoors and the LCD outdoors. However, the results indicate something far more interesting. Yes the AMOLED display was much better than LCD indoors, but it was surprising to note how evenly matched the displays were in direct sunlight.
What was more interesting was that the AMOLED display seemed more capable of displaying near black levels while the LCD was far better at displaying near white levels. The level of the ambient lighting seemed to have very little effect on this characteristic. What this means in everyday life is that on an AMOLED there is going to be more detail in dark areas of images while light areas will appear less detailed. The relative contrast levels therefore shifts as the intensity goes from black to white. It is not certain if this behaviour is an inherent characteristic of the display technology or that the display was engineered that way to increase the perceived overall contrast.
The LCD had exactly the opposite issue however it is easier to explain why. For dark shades, the contrast a limit of the display was set by the blending of the dark squares with the background but for white shades where the background effect was negligible, the LCD performance was far superior.
This implies that if the LCD could be improved such that there is less light leaked through black pixels then the overall winner in this comparison will be the LCD. This is the theory behind Super LCD but this is a relatively new technology available only on a few handsets.
AMOLED displays offer improved performance over LCD in indoor conditions, In direct sunlight, the AMOLED is able to maintain visibility on par with LCD. The display with overall better performance in all environments is the AMOLED one.
The LCD was better at differentiating between bright whites while the AMOLED was better at differentiating between dark shades.