Why? If you look inside the Camera Adapter, notice the eyepiece is deep into slot. When you look at a telescope, don't you need to get your eye really close to the eyepiece to see the whole view? That's the problem. We have to get the camera lens very close to the eyepiece. So close that they have to be almost touching.

The brick wall from the building next to our building. You are looking at the cement between 2 layers of bricks. Click on the picture to see the original size (620KB) picture. You can even study the composition of the cement.