help using the manual14x lens
 

Hi,
I just bought a canon 14x manual lens for my xl-1 and am having a lot of fun with it but at the same time am a bit confused.
With the auto 16x lens that came with the camera if I zoomed in or out on a subject, the subject would stay in focus, not so with this lens. Do I need to turn the zoom ring and the focus ring at the same time? Or use a dolly?
Also, if I have the apperature wide open at 1.6 and have the lens completely zoomed wide to 5.7 I cannot get ANYTHING in focus, no matter the distance. This was not the case with the auto 16x either.
Any help on this would be appreciated, as well if anyone knows a good site or a good book that could explain professional and creative lens/focus techniques I'd be a happy man.
Thanks,
Aren.

You need to properly adjust the back focus. There is a knob on the lens barrel close to the mount that you unscrew a little, not all the way, and then you can rotate the back focus. Put the camera on a tripod about two meters away from your subject and open the iris all the way. Zoom into a subject that has high contrast--a test chart on the wall works best. Focus on the subject as you normally would, with the focus ring on the front of the lens. Then zoom out to full wide angle and rotate the back focus until the image is sharp. Once you have a sharp image screw the knob in to lock the back focus in place and you are set.

After you set back focus as Will describes, lock it off and leave it alone. Then be sure to set Critical Focus every time you shoot: zoom all the way in on the farthest subject, and focus. Zoom back out. Everything in the zoom range will be in focus. Hope this helps,