Tuesday, February 02, 2010

Those rules about not using filters to create panoramic images deserve to be challenged

Arizona photographer Shane McDermott loves living close to many of our national parks and outdoor treasures. His impressive panorama views clearly reflect that feeling. "I would encourage any photographer to consider panoramas as an exciting way to celebrate nature on a grand scale," says Shane.

"Much has been written recently about creating digital panoramic photos, including how to capture them, stitch them and post process them. Of these three steps, capturing the image is undoubtedly the most important. In spite of all that's been written about panorama photography, however, I have come to realize there are almost no hard and fast rules.

"Creative photographers soon discover many of the rules are really generalities that can sometimes be either bent or broken to great advantage and that success will often depend upon the situation you find yourself in. For example, much of the current wisdom about panoramic stitching suggests that it's not possible to use original images taken while using a polarizing filter. It's argued that, as your camera's angle to the sun changes, the polarizing effect on the sky or vegetation will change, leaving the stitched image looking different from one frame to the next. Often this is the case -- just one of those generalities we must remember when out in the field.

"The good news is that this rule does not apply to every situation or scene. Your angle to the sun is a strong determining factor involved in the use of a polarizer, no doubt. But what if there is no direct sun, or if the sun is directly overhead, or it's a strongly diffused sun? What if the scene you are capturing is in the shade, or if the scene is a vertical shot or it's tight enough or small enough so that the polarization angle doesn't change much from frame to frame? Would any of these situations allow for the use of a polarizer? Absolutely, now we can start breaking or bending the rule about never using a polarizer for digital panos. Here are a few examples of some of the situations I have encountered over the years when creating digitally stitched panoramas.

"As I was preparing to capture the just-after-sunset image of Lake Powell seen above, I made trial exposures both with and without using my polarizer. (The image below was taken for comparison purposes from the same vantage point at sunset without any filter.) In the post-sunset capture (the first image of Lake Powell), I found I could indeed use my LB ColorCombo filter quite effectively. The camera angle and the fact that the sun had already set greatly diminished any uneven effect in the sky and dramatically transformed the light along the horizon. This allowed me to capture six individual frames and stitch them successfully.

"The Singh-Ray ColorCombo is an indispensable filter for my style of photography because it not only polarizes the scene it also enhances the colors, and possibly even tonal gradations. In fact, there has to be a very good reason for me to ever take the ColorCombo off my lens -- most of the time that's where it lives!

"I did capture this successful 6-frame panorama of Death Valley using my LB ColorCombo filter about 40 minutes prior to the image you see here. In this image, however, I was unable to use my LB ColorCombo because of the intensity of the sun which was now up and visible on the distant mountain tops. For this image I needed to use a Singh-Ray Graduated ND filter (2-stop hard-step) -- which many would advise against -- to create a multi-frame panorama. Although this can be tricky and generally takes some practice, it really comes down to the consistent placement of the ND Grad filter from image to image.

"This is also a six-image digital stitch, using my LB ColorCombo. This lovely scene represents about a 60-meter stretch of the Virgin River in Zion National Park. There was no direct light on this scene, but plenty of reflected light, for which the canyons of Zion National Park are famous. The high concentration of reflected light from the adjacent canyon walls was creating considerable glare on the water and vegetation surfaces, so I used the LB ColorCombo to eliminate this glare. As an added bonus, the LB ColorCombo also deepened the color intensity and slowed my shutter speed which softened the water surface even more, giving this image the dreamy feel I had hoped for.

"This image was captured approximately 30 minutes prior to sunrise. Again, due to my camera's angle to the rising sun, and the fact that it was all strongly diffused ambient light I was capturing, I could get away with using my LB ColorCombo filter. I captured six different frames from this remote area of Coal Mine Canyon and later stitched them together using Photoshop CS3, which is still what I use to digitally stitch all my panoramic images.

"So, I would like to encourage every nature photographer to play and explore with whatever is possible in the field. Be creative and have fun freely and imaginatively exploring the dynamic world of nature, utilizing all the tools of today's technology to push the boundaries of what you thought possible. It's only through relentless and careful experimentation that we learn when and how the rules can be broken."

To keep up with Shane's photo excursions and latest stories, you'll want to visit his website and his blog.

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