Straightening panoramas

Geschreven op Wednesday, October 4th, 2006 om 11:31

Stitching perfect 360×180° panoramas is not easy. Especially when shooting without a tripod or panoramic head. One of the most common problems is the misalignment of the horizon, and, consequently, everything else on the panorama: buildings, trees,…

I found an interesting link today about straightening panoramas (using panorama tools) on the Panotools mailinglist by Bernhard Vogl. His tutorial really helped me out on some panoramas which I was unable to straighten before. In particular this is what I’ll try to keep in mind while using PTGui:

• straightening is one of the last stages in the stitching process
• don’t use horizontal control points (only vertical ones)
• try to add one pair of vertical control points on each photo
• only add one pair of vertical control points per photo
• straightening is done in a separate optimization session, only affecting yaw, pitch and roll
• optimize using the panorama tools

DeFish settings for Nikkor DX 10.5mm

Geschreven op Wednesday, September 27th, 2006 om 11:43

DeFish is a simple Mac OS X program designed for de-fishing photographs taken with a fisheye lens and converting them to rectilinear or cylindrical projections. One of it’s goals was to demonstrate usage of technology already known before fisheye patents were “invented”.

I use DeFish on photos taken with the Nikkor DX 10.5mm fisheye lens. Especially when retouching the nadir (bottom) or the zenith (sky) of a full spherical panorama in Photoshop, you’ll appreciate its existence. Beware that it does not save EXIF data.

I had to search the net and some newsgroups to find the correct settings and parameters for my lens. Therefore I publish them here for those of you who might need it as well. Below are two screenshots of the ‘Fisheye Settings’ and the ‘Perspective Parameters’. You’ll need to change the rotation to 0° instead of 90° whether you shot in landscape or portrait mode.

You can also defish images using other software like Nikon Capture (Mac, Win), Lensfix (Mac) or PTLens (Win). DeFish works just fine for me though.

Planets from panos

Geschreven op Tuesday, September 26th, 2006 om 11:47

On Flickr I discovered a small group of people experimenting with different projections for their panoramas. Equirectangular panoramas (i.e. full spherical, 360×180°) can be warped in all kinds of mathematical shapes and views, often resulting in comical or just plain beautiful photography (yes, Seb Przd, I’m a fan).

The most popular alternative projections are ‘polarize’, ’stereographic’ and ‘hyperbolic’. They all result in images that look like minuature planets, much like we know them from Le Petit Prince d’Antoine de Saint-Exupéry.

The moment I saw all these little planets, I had to try it out myself. Since I only had a handfull of equirectangular images, my creative output was somewhat limited. Still, I’m quite happy with the result.