and THIS is exactly why you need Lens Align - there is simply ***NO WAY*** you are going to get that video box ***EXACTLY*** perpendicular to your camera/lens at the distances required (say 8' or so for a 100mm lens).
That is EXACTLY what the Lens Align system does - ensures that the camera and the target are PERFECTLY ALIGNED.
Wooo! Panic! I didn't have my focus target PERFECTLY ALIGNED! Woe is me! Waily Waily.
Hang on a mo. When I did my friend's 1D MkIII and 300 f/2.8 I didn't seem to have any problems doing it using a Mk1 eyeball.
Nope, the focus looks to be the same across the whole target! How strange, because it wasn't ***EXACTLY*** perpendicular?
Hmm, I wonder if it's got anything to do with the fact that the depth of field at 50xFL and f/2.8 is 29 cm?