Tamron AF 18-200mm f/3.5-6.3 Di II LD Aspherical (IF) XR macro - Review / Test Report
Lens Reviews - Canon EOS (APS-C)

Special thanks to Hans Link for providing this lens!

Introduction

Tamron is probably most renowned for its history of extreme range zoom lenses starting with the 28-200mm f/3.8-5.6 more than a decade ago. The idea went through various evolutionary steps till it finally reached its current incarnation - the Tamron AF 18-200mm f/3.5-6.3 Di II LD Aspherical (IF) XR macro (one of those mind-blowing Tamron names again ...). The Tamron is a dedicated lens for APS-C DSLRs with a reduced image circle recognizable by the Di II (Digitally Integrated II) part of the name. Di also refers to an improved coating of the lens elements to take care of the specific reflection characteristic of today's image sensor. The field-of-view of the AF 18-200mm is equivalent to ~29-320mm on a full frame camera. The lens is available in all major SLR mounts except Four-Thirds.

The optical construction is made of 15 elements in 13 groups including three hybrid aspherical lens elements, two LD (Low Dispersion) glass elements and one XR element. The XR (Extra Refractive Index) element is one of the key features of this lens. It bends light more efficient than normal glass thus allowing more compact lens designs. The aperture mechanism features 7 aperture blades. As you can see in the product shot above the lens is very compact with a size of 83x74mm and a weight of only 398g. The filter thread has a size of 62mm. The minimal focus distance is 0.45m resulting in a max. magnification of 1:3.7 at 200mm - therefore take the macro in the lens name with a grain of salt. A petal-type hood is part of the package.

The lens extends substantially when zooming towards the long end of the range. It does so using a so-called duo-cam mechanism with two inner lens tubes. Thanks to an IF (internal focusing) design the front element does not rotate so using a polarizer remains possible. The build quality of the lens is actually quite fine with pretty tight tolerances (aka no significant wobbling) but the subjective quality reception isn't all that great due to the used materials which have a distinctive plastic touch. The Tamron has also a plastic mount but the weight of the lens is surely light-weight enough so this compromise is acceptable. Both the zoom as well as the focus ring operate quite smooth. Unfortunately Tamron still didn't manange to implement a focus ring that detaches from the AF motor (in other words: it rotates during AF operations). The AF operation is reasonably fast but somewhat on the noisy side. Due to the very slow max. aperture at 200mm the AF can hunt in low light situations but the field performance is a magnitude better here compared to the Sigma AF 18-200mm f/3.5-6.3 DC.




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