[rollei_list] Re: rollei panorama head

It depends about the subject features and distance
camera-subject, if you have a geometrical (with curved
lines specially) subject very close to the camera the
perspective distortion exists making difficult to
stitch the frames, and then this is the reason it's
very important to "design" the pano previously
avoiding a division for two frames regarding
geometrical subjects in the foreground, no problem for
distant subjects if the rotation axis is right. More
distant the subject from the camera, less distortion
risk, this is the cause several Rollei TLR cameras
manual says the RPHead must be used for distant
subjects, but you can include closer subjects if you
take a good decision about the site to put them.
The pano software can solve or can create problems, it
works fine for little distortions, but it also could
create unnatural pano images.-

All the best
Carlos  
  
--- Richard Knoppow <dickburk@xxxxxxxxxxxxx> escribió:

> 
> ----- Original Message ----- 
> From: "Jerry Lehrer" <glehrer@xxxxxxxxxx>
> To: <rollei_list@xxxxxxxxxxxxx>
> Sent: Tuesday, October 23, 2007 1:18 PM
> Subject: [rollei_list] Re: rollei panorama head
> 
> 
> > Richard,
> >
> > Rolleigrip?  You mean Rolleifix, don't you?
> > Jerry
> >
>      I thought that looked wrong when I typed it. Of
> course, 
> Rolleifix is right. The older type is the first
> photo, the 
> newer one, the one that needs to be used with the 
> Rollei_fix_ is the second one.
>      I have one of the older ones and have used it
> several 
> times, I don't have the newer kind and have never
> worked 
> with one. The old one works very well and presumably
> the 
> newer one does too. Generally Rollei accessories are
> well 
> designed and do the jobs they are intended for.
>      Despite the experience of others the edges of
> Rolleipan 
> pictures need some help if they are to splice
> seamlessly. 
> The nature of lenses designed for single images is
> such that 
> objects at the corners are "distorted". This is not
> a true 
> distortion but rather is the result of making them
> appear 
> correct when the photo is viewed from the correct
> viewpoint. 
> This is on-axis and at a distance of either the same
> as the 
> lens or the equivalent distance times the amount of 
> enlargement. If you photograph a group of round
> objects, say 
> golf balls, arranged in a grid pattern you will find
> the 
> ones at the corners are egg shaped with the narrow
> ends 
> pointing toward the center of the picture. A flat
> grid, like 
> graph paper, is reproduced as equal sized squares. A
> little 
> thought will show that both will appear in the
> correct 
> perspective when viewed from the correct distance by
> one eye 
> on the optical axis of the print. For a panoram
> there is no 
> vanishing point but rather a vanishing line. At the
> seams of 
> the print three dimensional objects will be
> "distorted" as 
> above with the axis of distortion rotated by 90
> degees, as a 
> result there is a mis-match at the edges and
> corners. This 
> can be fixed optically but its difficult. The best
> results 
> are had by using an image editor program on a
> computer which 
> has a function for doing this specific corrrection.
> I am 
> pretty sure there is a plug-in for Photoshop and
> maybe the 
> latest version has it built in. I don't know about
> other 
> image editors. There is an elaborate freeware image
> editor 
> called Gimp which is available on-line but I have no
> 
> experience with it.
>      In any case its still possible to make
> acceptable 
> panoramas by just cutting together the prints.
> 
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@xxxxxxxxxxxxx 
> 
> ---
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