Note the barrel distortion in the following image — there seems to be some strange gravitational effect, perhaps located behind those trees; it looks as if the water is draining toward the center of the image.

This type of distortion tends to occur with telephoto lenses, even good ones, at the widest end of their telephoto range.

In this case, the lens is a Nikkor 18-200mm f/3.5-5.6G DX VR; quite a nice lens within most of its range. This particular shot was taken at 18mm, which isn’t where the lens does its best work. The funhouse mirror effect is quite unpleasant, and without correction, this shot would be garbage.

This type of distortion can be manually corrected in Photoshop, but that’s tedious, and the results are inconsistent, which is annoying, since a given lens will have predictable distortion, so the distortion should be correctable in a systematic and calibrated manner, just as in this corrected image:

This image was corrected by PTLens, which at USD $15 must be the best value in image processing available. Your $15 obtains all of the following:

• Automatic, calibrated correction of pincushion and barrel distortion, vignetting, chromatic aberration, and perspective, with hundreds of lenses supported.
• A standalone Windows application.
• A standalone Mac application.
• A Photoshop plug-in for both Mac and Windows.
• An external editor for Lightroom on both Mac and Windows.
• A plug-in for Aperture 2.1 or later on the Mac.

Note that the Mac support is Intel-only; PowerPC isn’t supported.

Since I’m an Aperture user, the Aperture plug-in is my weapon of choice. The utility is fast, intuitive, and the results are excellent.

A trial download providing 10 corrections prior to requiring a purchase is available.

I don’t think there’s any better value out there in image processing; this thing is a steal at $15.

Tags: Photography

Pictured on the right is the Father of the Forest, a 2000-year old, 250-foot giant redwood, located in Big Basin State Park. The shot was taken about 20 feet from the base of the tree, which is 66 feet in circumference.

We are fortunate to live in an area with many of these magnificent trees, and I love to take pictures of them.

However, the incredible size of these trees poses some photographic challenges; in short, they’re just too big to take pictures of — even with a wide angle lens, it’s impossible to fit something so massive into a single picture.

In fact, using an 18mm lens, moving from top to bottom, it took 7 shots to capture the entire tree. Now, that’s neat and all, but the result is a number of disjointed shots; it’d be nice to be able to stitch them all together into a complete picture.

Fortunately, we can, using panorama creation software.

This is a surprisingly competitive segment, with a number of solutions available. Almost all vendors provide downloadable demo copies, typically enforcing the demo license via a prominent watermark in the resulting stitched image.

In my opinion, the preeminent product in this space is AutoPano Pro, from Kolor.

AutoPano uses SIFT, developed at UBC, to perform its magic, and magical it is — one simply hands AutoPano a series of images, and it does the rest; stitching, lens and camera correction, exposure blending, ghost removal, color correction, and cropping.

Basically, it’s a fully automated solution, very simple to use, and produces great results without any effort. Handles the 14-bit RAW files produced by my camera without problems.

The one downside to the program is the UI, which appears to be QT-based. This isn’t surprising, as a Windows and Linux versions of the program are also available, and Kolor isn’t a big shop; it makes sense for them to use a cross-platform toolkit. However, the result is that the UI looks a bit odd from the Mac perspective.

However, that’s but a small complaint in what is otherwise a fantastic utility.

AutoPano Pro is 99 Euros. A free, watermarking demo is available.

Highly recommended.

Tags: Photography