I am very new to NEX 5, and I found that the pancake lens (16mm F/2.8) cannot focus on very near object (capturing big size image of a small object), the nearest focus point of the lens is around 13-15cm from the lens. While playing with the NEX 5, I found out a method to capture very near object (small object) using the pancake lens.
The first step is to set the largest aperture on the lens, F2.8, and remove the lens from the camera. This step is to make sure that the aperture on the lens is at the F2.8 after it is removed. Then, align the lens in between the camera and the object. Something like shown in these images:
The lens is not attached to the camera:
Adjust the distance between the camera and the lens to focus on the object. You can use the MF Assist on the camera for better focus, you can also try to tilt the lens to get different blur effect:
Some sample image taken using this method on 16mm F2.8, (not cropped, direct from the camera without any processing, only resized and watermarked):
I think this is definitely something to tryout using NEX and the 16mm pancake lens. It gives very different output from the camera using that combination (NEX and 16mm pancake lens) compare to the attached normal method. One thing to pay attention on this method is to hold the camera and the lens tight, and do not drop or scratch the lens while adjusting the focus. Have fun!