Axial Adjustment for Cameras with Tripod Mount off the Lens Axis
After you have corrected the tripod mount off-set. You need to determine the axial
adjustment, i.e., the distance from the tripod mount to the entrance pupil position. You can find
the values for most camera-lens combination on the internet. If the value is not available, you
have to determine it yourself. There are various tutorials on this subject across the internet. But
most of time, the entrance pupil position is mistakenly referred as the nodal point. So you would
like to search for “nodal point determination” or something like that. You can also read my
tutorial “Locating the Entrance Pupil—a systematic approach” at the end of this manual. This
new approach is particularly easy to use for digital cameras with a live video out function.
Assuming you know the entrance pupil position, e.g., 41mm in front of tripod mount for
Dimage 7 series at 28mm focal length, what you need to do is mount the camera onto the
vertical rotator arm through the off-axial adapter. There is a mark at the back of the off-axial
adapter which corresponds to the center of the tripod mount. So you slide the adapter to 41mm
by reading the scale on the vertical rotator arm. Check that the surfaces of the adapter and the
vertical rotator arm are parallel before you fully tightened the knob. You can mount your
camera with the handle up or down (if your camera is not too bulky), as there are scales on both
sides of the vertical rotator arm. Mounting the camera with handle down helps to lower the
center of mass and hence increase stability. Now, you are ready to take as many panoramas as
you like. But before you fire the first shot. You should level the whole assembly first. Adjust
your tripod head until the bubbles in the spirit level remain at the center. The spirit level in the
bracket has been calibrated against engineering grade spirit level during assembling.