I looked at many iphone 5's at the apple store and some that my friends own and noticed an interesting correlation between the serial number and the screen quality. Another post is talking about the same issue, and these screens have apparent vertical lines which makes the screen look grainy and chunky. For me, it made my eyes sore when I roll my eyes over the screen or when the screen moves when I type. http://forums.macrumors.com/showthread.php?t=1451439&highlight=screen+quality One thing people have seen on these screens is continuous flickers when the attached image is set as the home screen. I took it from the post above and bigcstyle4 posted it on the 53rd reply. I just got curious if this is really a correlation between the serial number and the screen quality. Please post the first 2 letters of your serial number(F1 / F2 / DN / C3) and what you see when you set the image as your home screen. == UPDATE The real issue that bugs us is the vertical interlaced lines which distort the image during everyday usage. However, other people discovered that the attached image flickers when put as the home screen or the lock screen on displays that has the interlaced line issue. This is why the attached image is emphasized. Summary of what to look for - Steps to reproduce 1. (optional) Set the display brightness to high, because that is known to make you see the flickering much easier. 2. Set the attached image to the home screen and the lock screen. 3. Observe the lock screen and the home screen. - What you will see on a screen with the vertical interlaced lines. 1. Lock screen: The screen will flicker. The gray areas on the top(where you see the status bar, date, time) and on the bottom(where you see "slide to unlock") will flicker the most. 2. Home screen: The screen will flicker. The gray areas near the status bar and the dock will flicker the most. - Flickers and discolorization when things are moving does not indicate any problem. It is expected and normal. This is discussed in reply #35(written by me) and #75(written by Bahroo). The gist is that the software has to approximate the color to put on a pixel when the displayed image does not perfectly align with a pixel. The attached image has 640 black and white lines alternating and the lines are exactly one pixel wide. When this image is moved or resized on the screen, it is very likely that the lines will land between pixels, but since a line is only one pixel wide, the color for the pixels spanned by a line is approximated.