Re: Seitz Roundshot and QTVR technique

[Joshua Eskin <josh@xxxxxxxxxx>]

Jook Leung wrote:

> Do users set their lens focus at infinity and put that value into the
> RoundShot or can I apply closer focus setting and use hyperfocus-depth of
> field/f-stop settings to keep infinity also in focus?

I don't have much experience with the RoundShot, but I use the Sigma 14 on
my digital pano cameras.  When used full open at f/2.8, I need to set the
focus to 0.7 or 0.5m to have most near and far objects in focus.


> The term "Nodal point" is only mentioned once in the manual and is not
> normally accounted for as it is
> in other QTVR rigs. So that was absolutely confusing.

Don't worry about the nodal point in a slit-scan camera.  It is a problem
for QTVR rigs because when stitching you need to match up the left side of
one shot with the right side of the next shot.  If the shots were not taken
from the nodal point, the effective point-of-view will have changed as the
camera rotated.  If a slit-scan camera rotates from other than the nodal
point, the change in viewpoint is gradual.  And, since the film is only
recording the portion of the scene looking straight ahead, the effect is all
but unnoticeable.

> Yikes, horizontal bands of flare at bottom of image: Taping a curved piece
> of black paper over the backside of the compendium will take care of the
> flare problems of the Sigma 14mm lens.

I get those bands too.  Can you say more about how you do this masking?
What is the backside of the compendium?


=Josh
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  Joshua D. Eskin, Ph.D.  Panoptic Vision, Inc.,  Boulder, CO
  Voice: 303-417-9800   Fax: 303-440-6162      www.pancam.com
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