Most optical center data that is available on this website and from other resources on the internet provide you with a number that represents the distance from the center of the tripod hole of your camera to the optical center (or entrance pupil) of the lens.  This number is typically expressed in millimeters.   The Pansaurus has markings on the upper horizontal arm that represent this same distance.   The Panosaurus Rex has markings on its metal arm that represent the distance from the center of the tripod hole to the optical center PLUS the distance from the center of the tripod hole of your camera to the back of the Panosaurus Rex camera mounting block. Please see the diagrams below for a better understanding.
 

Panosaurus

Understanding the ruled lines marks on the Panosaurus Upper Horizontal Arm.

1. If your camera is NOT a DSLR style camera and the tripod hole is offset from the centerline of the lens then you will read the centimeter marks that correspond to arrow 1 below.

2. If your camera is a DSLR style camera and the tripod hole is aligned with the centerline of the lens then you will read the centimeter marks that correspond to arrow 2 below.

3. If you need to slide the camera mounting block of the Panosaurus so far back on the horizontal arm that you no longer see the upper ruler marks - you then use the lower marks and read from the front of the camera mounting block - see arrow 3 below.

4.  Arrow number 4 in the image below represents where the BACK edge of the Panosaurus camera mounting block would be placed if the distance from the center of the tripod hole of your camera to the optical center of the lens is 106mm (using a DSLR camera) or 86mm (If using an offset tripod hole camera).

5.  Arrow number 5 in the image below represents where the FRONT edge of the Panosaurus camera mounting block would be placed if the distance from the center of the tripod hole of your camera to the optical center of the lens is 156mm (if using a DSLR camera) or 136mm (if using an offset tripod hole camera).

 

 

 

 

 

Panosaurus Rex

Finding the distance from your tripod hole to the back of the Rex mounting block.

To use the ruled lines on the Panosaurus Rex metal arm correctly you need to not only know the distance from the center of your tripod hole to the optical center of the lens (Fig 1 in picture below)  but you also need to know the distance from the center of your camera tripod hole to the back edge of the Rex camera mounting block (Fig 2 in picture below.  You then add these two numbers together.   This summed number is the number that is used when mounting to the metal arm of the Rex.

In order to measure the distance from the center of your camera tripod hole to the back edge of the Rex mounting block simply mount the Rex block to your camera using one of the 1/2" bolts normally used to attach the block to the metal arm (see picture below).  Then using a millimeter ruler measure from the center of the slot of the bolt to the back edge of the Rex mounting block.  NOTE:  You do not need to thread the bolt into your camera fully but make sure the back-stop block is flush with the back of your camera when doing your measurement.

 

 

Understanding the ruled lines on the Panosaurus Rex Metal Arm.

1. If the metal arm has been attached on the Rex rotator like the top left image below then you use the top ruler marks to determine distances.

2. If the metal arm has been positioned on the Rex rotator like the bottom left image below then you use the bottom ruler marks to determine distances.

3. EXAMPLE:   Arrow number 3 is pointing to 152mm.   This represents the distance from the optical center of the lens to the center of the camera tripod hole PLUS the distance from the center of the camera tripod hole to the back of the Rex camera mounting block.  When mounting your camera the BACK edge of the camera mounting block would point to this number.

4.  EXAMPLE:   Arrow number 5 is pointing to 186mm.   This represents the distance from the optical center of the lens to the center of the camera tripod hole PLUS the distance from the center of the camera tripod hole to the back of the Rex camera mounting block.  When mounting your camera the FRONT edge of the camera mounting block would point to 186mm.

5.  EXAMPLE:  Arrow number 4 is pointing to 86mm.   This represents the distance from the optical center of the lens to the center of the camera tripod hole PLUS the distance from the center of the camera tripod hole to the back of the Rex camera mounting block.  When mounting your camera the BACK edge of the camera mounting block would point to this number.