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Good grief! Four successive versions of the same 28–200mm f/3.8–5.6 AF Tamron lens!
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1992 dawn of a new zoom day: Hurrah! A convenient, light, relatively small 28–200mm Tamron appears, but with limited close focusing, only at 200mm; better with extra accessory close-up lens. |
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1996 At last, close focusing: Second lens designer revises Version I, keeps same basic optical design, but provides variable-distance close focusing at all focal lengths and improved optical performance. |
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1999 Same basic design: But two inches chopped from length, and close focusing to 19 inches at all focal length settings, with 1:4 magnification at 200mm. Optical performance improved and distortion minimized (as it would be with each successive model). |
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2001 Major miniaturization: One less element, four ounces lighter, 1/4-inch shorter, with diameter sufficiently reduced to accept 62mm accessories, rather than the 72mm of Versions I, II, and III. Same close focusing retained. An amazing engineering feat! |
Tamron 28–200mm lens owners are giving me multiple guilt trips with no end in sight. During 1992, thanks in part to my enthusiasm, scores of you bought the original 16-element, 14-group, 28–200mm f/3.8–5.6 Tamron lens. Distortion was somewhat high, and sharpness was not optimal, particularly at 200mm. But oh, what fun to use this 15-ounce, 3 1/4-inch-long lens. Virtually everyone was delighted with the incredible convenience, fast operation, and fairly close focusing to 1:6.9 (5 feet, 3 3/4 inches) at 200mm. We recommended an accessory close-up lens for those needing greater magnification.
Readers who bought the lens were happy campers. But there was one unhappy camper: Tamron’s president. He had written the lens’ specifications, and one spec had been missed by a mile—close focusing at all focal lengths. So he called in a second optical designer.
In Version II, the president got what he wanted. While keeping to the same size, weight, and convenience of Version I, the second optical engineer provided variable close focusing at all focal lengths, with maximum magnification of 1:4.6 (15 inches) at 135mm and 1:6 (23 inches) at 200mm. Subjective Quality Factor figures were improved at short and medium focal lengths, and distortion was minimized.
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