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Tuesday, March 22, 2011

Convert A DSLR To Infrared


Seeing Color In Infrared • Making Sense Of Print Size Ratios • Big ’Scapes Need More Space • Kolor Autopano Giga 2.5 For Difficult Panoramas

Labels: How-ToColumnTech Tips

An infrared image taken with a Canon PowerShot G11 compact camera converted to infrared by Life Pixel. The photo was taken in the Namib Desert, Namibia, Africa. The RAW file was modified for additional color in Photoshop CS5 by reversing color channels. 1/60 sec., f/3.5, ISO 100

Seeing Color In Infrared
Q I’ve seen a lot of digital infrared landscapes lately. Some have different colors in the image that add an element of drama that I don’t see in pure black-and-white infrared. How is this done? I’m about to convert a DSLR.
J. Schmidt
Via the Internet


A Digital SLRs are very sensitive to infrared (IR) light, so they normally have an internal filter that keeps IR rays from reaching the sensor. When a DSLR is converted to infrared capture, the IR cut-off filter in front of the sensor is replaced with a filter that allows only IR light to pass through. The resulting images are black-and-white, with interesting shifts: Vegetation, for example, turns white; blue skies are rendered black.

Recently, there are more options in IR conversions that retain some color. Life Pixel (www.lifepixel.com) offers three color versions. The first is the Standard Color IR Filter that records from the sky a slight amount of blue that can be adjusted from red to blue in Photoshop. The Enhanced Color IR Filter has greater saturation and color range. The Super Color IR Filter offers vibrant, surrealistic effects. The website shows examples of each of the filter options. The hard part is choosing just one. Note that many compact cameras can be converted, as well as DSLRs, so now you have some new options for rehabilitating your previously used digital cameras.

Making Sense Of Print Size Ratios
Q I'm having difficulty figuring out what print/mat/frame sizes best correspond to images taken on my Canon EOS 40D’s native 3x2 sensor. I’d like to print some large photographs, but I’m not sure how to standardize to available frames and mats. Is it better to crop the image to fit? If I choose oversized mats to accommodate my format, is it better to leave more space on the sides for landscape view and less for portrait view, or vice versa? Finally, is there a formula for bottom weighting the photograph? I’m seeking a happy medium without too much custom framing involved.
A. Curtis
Morgan Hill, California

A I feel your pain. Traditional paper, mat and frame sizes (8x10, 11x14 and 16x20) are keyed to 4x5 large-format cameras that once were the standard for portrait studios and press cameras. And papers for today’s inkjet printers are still reflecting sizes relevant to the printed page—8½x11, 13x19 and 17x22 (a two-page signature). So where do any of these standard sizes fit with the 35mm film size or today’s digital sensors, with their 3:2 aspect ratios? Once you get beyond the 4x6 print, they don’t.

It’s not just a factor of the digital age. I remember the frustration of sending my 35mm transparencies to the lab for printing; they offered only the 4x5-compatible sizes. Their solution was to crop off one end of the image so that it would fit on their paper. Not acceptable! So I invested in custom prints on larger stock, trimmed off the excess white paper and had the work professionally framed. Another more economical option was to order a custom mat with a window appropriate to the print and external dimensions appropriate to a standard frame.

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