Compare Sigma 28-300mm f/3.5-6.3 Macro for Pentax AF to Tamron A14 for Pentax

Sigma Corporation is pleased to announce the availability of the new 28-300mm F3.5-6.3 MACRO lens. Ultra compact dimensions, length: 3.3", diameter: 2.9", Filter Size: 62mm and a 10.7:1 zoom ratio make this lens the ultimate traveling companion. This versatile, all-purpose zoom can capture a wide ranging series of subjects using its wide angle, ultra-telephoto and close-up capabilities. It incorporates 2pcs Special Low Dispersion SLD glass elements and 4pcs Aspherical Lenses, to produce a high level of optical performance. Aspherical lenses provide excellent correction for all types of aberration while making a very compact construction possible. This lens has a minimum focusing distance of 50cm at all focal lengths. Equipped with a macro mechanism for close-up photography at 300mm telephoto, with a reproduction ratio of 1:3. It is equipped with a "zoom lock" to prevent the zoom setting from being changed inadvertently. It incorporates an internal focusing system, which eliminates front lens rotation, allowin Less

Tamron AF18-200 Di II Telewide Lens
At Tamron, our quest has always been to make the ideal zoom lens. As a result of this ongoing challenge, we have introduced the concept of our high-power zoom lens in the new AF18-200mm XR Di II for exclusive use with digital SLRs. Tamron's original development of proprietary core technologies such as Aspherical element production, Multiple Cam Mechanism and Integrated Focus Cam design lend to the creation of the world's lightest, most compact 11.1X zoom lens made for digital SLR cameras. Less