A Lightweight M-System Using the “Crop Factor”

Jun 6, 2016  By Dick Gilcreast


In the good old days of Kodachrome, color photographs were submitted to publishers in the form of slides for best reproduction — not prints, as had been the case with black and white. Therefore a pro photographer specializing in color was obliged to carry SLR cameras with a considerable range of fast lenses in order to get each shot framed correctly for submission to editors. Zoom lenses were slow and heavy and not very good, so it was mostly up to a set of individual prime lenses to get the shots framed correctly on the slow slide films of the day.

A lot of that changed with the take-over by digital. Color pictures could then submitted electronically which allowed cropping of the pictures before submission — and/or small corrections to the images — made by the photographer using  computer programs such as Photoshop. The ISO in the camera could be increased when light was low so the lenses could be slower, even if the image quality deteriorated a bit when the ISO was pushed too high. However the total weight of equipment  carried all day in the bag didn’t change much. It now consisted  of one or two DSLRs with rather large and heavy zoom lenses  usually in three ranges — superwide such as 12-24mm, normal 24-70mm, and longer telephoto. Total weight was still approaching  the twenty pound range.

With slide film the M camera and lens set was somewhat  smaller and lighter, if we could do without the longest focal lengths and macro capability. A typical M set was 21-28-35-50-90-135, ignoring newer in-between lengths such as 24 and 40 and 75. Five or six lenses were usually needed in the bag to frame the slides. And usually two camera bodies needed so that two prime lenses could be used at the same time This meant that weight and complexity were still somewhat of problem.

But if weight has already begun to be a problem, digital  submission has provided a particularly good solution for color  work, especially with the M cameras. Courtesy of the new “Crop Factor”, as I like to call it, we can now cut that six M lens rig exactly in half by carrying only 21 and 35 and 90 with each lens doing the work of two or three. This is how it works:

Take a 35mm M lens, for instance. Small, light, and fast, used in its “normal” mode it does just about anything from a large landscape to a small group in extreme low light. But what if a 50 is suddenly wanted for an individual portrait or a middle distance shot? The old way was to take the time to switch to a 50 or use a second camera with a 50 on it so the slide was  properly framed. But now, with cropped electronic submissions, we can use the 35 in horizontal mode and crop the picture square to look just like a 50 shot. Since the short side of the 35 picture is the same dimension as the long side of a 50 frame, a squared-oft 35 shot is therefore made at the same distance as a vertical or horizontal 50 shot, and showing the same perspective. The 35 can now do the work of two lenses — much the same as the old days of b&w and the home darkroom — but these days with ISO 400 color neg film or digital there isn’t the grain that Tri-X used to show when blown up and cropped.

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