Friday, August 31, 2007

Ginny Bloggin' P2

Yesterdays entry got interupted so here's more on the Ginny.

The core of our products is always the lenses. We use Carl Zeiss lenses. A lot of you are familiar with the ReActive series of Photochromic lenses. The one the Ginny sports are a different series. Carl Zeiss refers to the as Field of Play. Each lens sports a color designed to enhance visual accuity. For the high tint lenses the color is green. Green is a medium contrast color that opens your retina somewhat to enhance texture and depth perception, but not a lot. The medium tint lens sports the tried and true red coloration, which is a high contrast.

Matching color and tint can be a challenge. Since coloration starves the retina of specific light waves causing it to expand, you want to be carefull to pair it with a complimentary tinit. For example, since the red lens is hicontrast, it's not really a sunlens. So you wouldn't pair it with a heavy tint since that's for bright days. By putting a green color on the dark tint lens you open the retina a bit, but not a lot. So you get the benefit of some enhanced contrast, without your retina basically running around completely naked in the baking sun.

Carl Zeiss's field of play series is also Polycarbonate, unlike the photochromic lenses which are CR39. That really big marketing company from California has spent millions of dollars to convince you that PC is the best thing ever. The reality is that any material used or design chosen has benefits and costs.

PC's primary benefit is it's impact resistance. It passes ANSI's highest impact standards and essentially qualifies as a "safety glass". On a practical level that means it's "safe" to use for shooting, construction, motorcycle riding or other activities where objects may hit you at very very high speeds. The famous example is the construction worker who shot himself in the face with a nail gun. The nail impacted and penetrated the lens but did not hit his eye. Whew!

Another advantage is thickness. PC lenses are thinner (and, coincidentally lighter) than CR39 lenses. This allows more flexibility in frame design because the lens is easier to cut into a frames bevel. What does that mean? The Ohop uses a CR39 lens and a major challenge is cutting the lens so that it stays in the frame. Because it's thick the whole lens doesn't go into the bevel. It has to be tapered. Additional the extra thickness of the CR39 means that if you flex the Ohop the lens will not flex as well... flex it enough and pop out comes the lens. The thinner PC lens on the other hand fits right into the bevel with no taper. And because it's thinner and PC it will flex with the frame to a greater degree. So you get greater lens stability.

Now that doesn't come without a cost....

PC lenses may be thinner, lighter and more impact resistant than CR39, but they also have lower inherent optical quality and clarity. Put bluntly, PC lenses tend to shoot lightwaves off at angles, appear cloudy to the eye and generally are hard to see through. But many companies have worked long and hard to correct these problems. It looks like the industry as a whole has made great strides towards using decentered lens and proper cut techniques to improve the visual clarity. On the otherhand, many of the lenses used by mid-level and low-level companies still seem to be pretty low quality.

Carl Zeiss's field of play lenses seem to have both nailed. The lenses are crisp and clear, and the decentering means outstanding clarity. We use Zeiss because while they can be pain to work with one of the reasons they are a pain is that they won't hesitate to destroy entire runs of lenses that don't meet their exacting standards. As an aside Carl Zeiss does not currently offer PC Photochromic (ReActive in our parlance) because they do not feel that the 2 technologies have been properly married yet. That's why our ReActive line uses CR39: we only use Carl Zeiss and so far PC Photochromic lenses don't match the optical quality they demand.


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