I thought that I should back focus my new camera JVC HM 700 with the Canon 14-1
lens , boy tht was a mistake now after unsuccessfully trying for a 6 th time everything zoomed out looks softer. I have tried so many times . I am frustrated could i have damaged the lens ? I just loosened the back focus screw and thats all i did. I know how to back focus
so I am confused ?


Doug

While I don't have that lens, setting back focus is about the same.. You might even have a chart in your JVC paperwork.

Anyway, find something with lines in the distance and zoom in all the way. Focus normally. Pull full wide, set the back focus to make it sharp. Repeat until both zoom and wide positions stay in focus. Lock down back focus.

Don Smith
NewsVideo.com

Tips for successful backfocus adjustment:


OPEN THE APERTURE ALL THE WAY TO SHORTEN THE DEPTH OF FIELD (if it is too bright you should increase the shutter speed and avoid using the ND filter)
If you don't have an external monitor then turn down the peaking (about 25%) and turn off focus assist for the camera so that they don't deceive you.
Zoom in, front focus, zoom out, back focus, then repeat TWICE!

I find a chain link fence about 60 feet away makes a great back focus target. ND on max and run the shutter speed up to drop the aperture and i'm good. And I do it about 3 or 4 times because I'm weird.

While I've done back focus the way Alex describes, the process should work better if you follow the 10 feet to target, lens wide open (using shutter and ND if necessary) zoom in, set focus, pull back, set BF, check method BECAUSE you will be able to see much more conclusively whether the test target (or other object, like a fence) is in focus at 10 feet MUCH easier than at 60 feet. As well, the closer to the lens the object is, the more critical focus is. As your distance to target focus increases, so does the DOF.

I make my backfocus round about 3 to 4 m,
that was the first what I usually make after
a lense change and check the backfocus before
important shots.
I got no problems in backfocusing,
in the HM700-Manual is a good way to make your
backfocusing.