Back Focus

What is back focus?  How does affect the image that you are shooting? How do you check the back focus?  Are our JVC camcorders different than the Sony EX3?  How?  What are the key differences between adjusting the back focus?

    Back focus is the distance between the rear lens element and the camera sensor. It affects the image while shooting as having an issue with the back focus can lead to the image losing clarity when zooming in or out. In order to check the back focus, you must zoom into a hard edge and focus it before zooming out fully. If the image goes out of focus, then there is an issue with the back focus. In order to fix it, you can use a Siemens Star by zooming into the center of the chart, focusing it, zooming out, then adjusting the back focus. You should repeat the process around three times in order to properly set the back focus. The JVC camcorders are different than the Sony EX3 as most lenses allow you to adjust the back focus on it, but the EX3 handles it within the camera.