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Shot of the Nadir Images with Hardware Assistance

21 november 2005

A new spherical panorama head

This new model of panorama head is the evolution of an older design that was first dedicated to the Nikon Coolpix 990 and later on adapapted for the REBEL Canon EOS 300D.

The Azimuth orientation (Called "Yaw" in PTools) is now done by the "Slim Rotator" device. It possess two significant features: slimness and very accurate position registration.

The external Diameter of the tube is 22mm and reduce considerably the obstruction done by a standard Panohead.

Click on picture to enlarge

Canon EOS 20D, Sigma 8mm, new panohead et new LASER support.

One can see Slim Rotator just under the Head: I have made a 4 stops version first then a 10 stops and the 6 stops last version that is shown here that just got out from the shop.

The panorama head is shown in the regular position. It is not yet set for a Nadir shot: the camera is having the lens looking downwards but still along the axis of rotation. The vertical arm shall now be flipped over by 180 degrees for the Nadir Shot? See the next picture:

Click on picture to enlarge

In this flipped-over position the tripode and the panorama head are not in the Center of FOV of the lens anymore.

The tripod was moved in such a way to have the LASER beam hits the ground exactly at the place where the base of the center mast was before the move (the position that was set to shoot the lateral photographs and the Zenith).

It is essential to have the shaft vertical all along the process. A special Spirit level is an very inexpensive way to keep it vertical.

Two photos are shot from two opposite position exactly symetrical around the position of the rotation axis. This allows the merging of two images in PTGui 5 and insure that the complete Nadir is sharp and free from obstruction. Details for this complete process are given here.

Dual LASER support (SuperPhilopode)

Preamble

This device is not really necessary while the Nadir shot is done on top of a tripod (as described above). Then only one of the two LASER pointers is operated.

This new support is mainly intended for assistance during a hand held Nadir shooting or perhaps on a tripod when the terrain surface is rough enough to make Nadir shooting difficult without this assistance.

Description:

Modification of the previous system allows to add the second LASER pointer.

Each LASER pointer can independantly be oriented around two axis of rotation. As shown on the photo, the model is still at the prototype stage.

When the camera is in the configuration shown above (top of the page) the two beam are set to be coincident with the foot of the shaft. A mark is made on the ground (I use a penny for that purpose). By reproducing the same coincidence when the camera has been flipped over (see above) the center of the photo is the Nadir of the Panorama. Of course this could be done With or Without the tripod: the green spirit bubble level insures correct verticality of the optical axis of the lens while the dual LASER beams insures both correct altitude and correct pointing .

I have tested the system to check that the Nodal Point of the lens is kept in a sphere of about 6o mm in Diameter (this is for an altitude of about 1.4 meters, hand-held).

Michel Thoby