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High Definition production of movies and television is becoming part of the everyday experience. Issues previously addressed when working with film are coming up again in the HD world. Until recently, the use of a zoom meant visually downgraded performance. Because of today's advanced computer design and modern lens making materials, the quality of fine zooms has improved dramastically. So how does one choose between using a zoom or a set of primes? Mostly, it comes down to COMPROMISE. It's about give and take: what do you get and what does it cost you? How valuable is what you are giving up and how important are the advantages you gain? At Carl Zeiss Optics cine lens division, lenses are designed and built in a process that strikes a delicate balance. Materials, coatings, placement of elements and mechanical precision are all factored in to produce a lens that performs to precise, pre-determined criteria. DigiPrime® lenses are the most advanced example of the fine art of lens design. The design and manufacture of a zoom requires added challenges due to greater size, weight, glass elements and the need to image at various focal lengths. There are advantages and trade offs. The finest designed and crafted prime inherently offers the best optical performance. Today's best zoom can come close, but when image quality is of foremost priority, a great prime can't be matched. Though larger and heavier, the chief advantage of a zoom is that a single lens offers a range of focal lengths. For example, a 5-50mm zoom functionally replaces a 5, 7, 10, 14, 20, 28 and 40mm prime. Unfortunately each zoom focal length is a compromise compared to the equivalent prime. With a more complex optical design, zooms require more lens elements so there's more glass to air surfaces, thus multiplying imperfections. To sum up, choose carefully and conscientiously. Test before shooting — zooms against primes, lens against lens. There are many great choices. That's why I urge you to test DigiPrime® lenses to see why DP's the world over say, "There's no better image than with a DigiPrime." HOW IS CURVATURE OF FIELD ON THE WIDE END OBSERVED WHEN USING A ZOOM? Wide-angle primes have built-in correction to compensate for curvature of straight, horizontal and vertical lines for a single focal length. Zooms correct less because they need to serve many focal lengths-wide and telephoto. HOW IS BREATHING OR PUMPING OBSERVED WHEN USING A ZOOM? As focus changes, the image changes size. For example, on a long tracking shot, an actor walking toward camera might get smaller the closer she gets. HOW IS EXPOSURE RAMPING OR F DROP OBSERVED WHEN USING A ZOOM? As a lens gets to the end of the zoom range, the light reaching the image lessens and exposure drops. HOW IS LATERAL CHROMATIC ABERRATION, AKA COLOR FRINGING OBSERVED WHEN USING A ZOOM? More problem with zooms due to design complexity and more glass to air surfaces. ADVANTAGES OF WELL-DESIGNED ZOOM LENSES:   1. Saves time changing lenses and back-focusing   2. Less cost to purchase or rent.   3. Can accomplish small framing adjustment without moving camera   4. Ability to perform a live zoom within a shot. ADVANTAGES OF ZEISS DIGIPRIME® LENSES:   1. Superior image quality. Sharper and best saturation of blacks, etc.   2. Nearly no breathing or pumping when holding focus   3. Minimal veiling glare and flare (which muddy blacks and reduce color saturation)   4. Smaller size, weight & C.G. |
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