It's becoming more and more obvious that the days of film photography are ending and digital is taking over. Almost all of the big film manufacturers have either disappeared or have moved over to digital, and now it seems like lenses are following suit with another digital-only lens, this time from Tamron - the AF18-250mm F/3.5-6.3 Di-II LD Aspherical (IF) Macro.
This lens isn't big news just because its digital only (although that helped) but because of its huge high power zoom range. It is capable of a zoom ratio of 13.9x which at the moment is certainly Tamron's biggest, and is most likely the biggest anywhere else on dSLRs at least. The lens' focal length covers from 18mm wideangle to 250mm telephoto and it was introduced as a digital alternative for photographers using Tamron's other high zoom lenses - and to bring simplicity to photographer with a “one-does-it-all” concept to the lens at both ends of the scale. It has a minimum focusing distance of 0.45m throughout the zoom range, and has a macro ratio of 1:3.5.
It's also an interesting lens because of its size, while you'd expect a lens with this zoom range to be pretty large and bulky, it isn't. The smaller dimensions of digital sensors can account for a bit of this, Tamron have worked hard to remake the optical design of the lens to save space. It measures 74.4 x 84.3mm and only weighs 430g.
The advantages of being exclusively digital is that the lens is the correct size and ratio for the sensor, being 4:3 and smaller rather than film's 3:2 sensor. The insides of the barrel and the lenses are all coated to prevent ghosting and flare caused by reflection from the sensor. Since Tamron doesn't have a camera mount of its own, everyone can gain from the lens being available for lots of manufacturers, and it fits APS-C sized sensors. These are the Canon AF, Sony/Maxxum AF-D, Nikon AF-D and Pentax/Samsung AF.
Unfortunately no release dates or prices have been announced as yet.
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