Instruction manual

Instruction Manual Roundshot D3 - version 4.05 – May 2013 - © by Seitz Phototechnik AG / Switzerland www.roundshot.ch page 70
4.9 … create spherical QTVR panoramas (continued)
Currently there are three fisheye lenses which are suitable for spherical QTVR
panoramas and which can be calibrated at the Seitz factory for this purpose:
Lens Image circle
at f=11
(and focusing at
infinity)
Vertical
resolution
(pixels)
Approximate
field of view
8mm Sigma fisheye f/3.5
16mm Nikkor fisheye f/2.8
24mm Mamiya 645 fisheye f/4.0
22mm
43mm
70,5mm
Resolution
after
calibration
(pixels)
To capture the extreme points (+/- 90°) the fisheye lens is distorted, ie it has a non-
linear behaviour for the last few degrees.
The purpose of the lens calibration is to correct this non-linearity and to optimise the
camera hardware to minimise any potential error.
The calibration is done on a special calibration bench at the Seitz factory and includes:
• measuring of the lens and computation of a lens-specific mapping function
(calibration file/software); the calibration file is added to the camera software
• digital back blocker: new pressure bolts to lock the digital back and to avoid any
lateral or vertical play
• shift blocker (to fix the vertical shift)
• focus ring blocker (fixed distances 2m, 7m**)
• lens mount blocker (the lens cannot be detached from lens mount)
• nodal bench blocker (to always have the exact position on the nodal bench); 2
blockers are available for 2 standard distances: 2m, 7m**
• digital shift: correction of vertical position of sensor (to compensate any mounting
differences of the sensors); this is included in the lens calibration file
2,750
5,400
7,450
With Seitz D3 digital scan back
3,063 x 6,126
6.216 x 12,432
7,800 x 18,770*
* For the 24mm Mamiya fisheye lens the software automatically adds a black border at the lower edge of the
image to create the 180x360° format. With this black border the image dimensions are: 9,385 x 18,770 pixels
180° x 360°
180° x 360°
150° x 360°
** Corresponds to 7m on focal mount of the lens – this focusing allows optimum depth of field up to infinity
(hyperfocal)
The calibration blockers can also be removed from the camera and the Roundshot D3
can be used freely with different lenses to create a variety of image formats.