The Tamron AF 70-300mm F / 4-5.6 Di LD MACRO 1: 2 is one of the best lenses ever. Although it has a plastic case, it does not look cheap, but feels quite robust. It offers a highly sought focal length range (to APS-C cameras 112 mm to 480 mm effective focal length KB) - but without image stabilization, which is why you probably often has to rely on a tripod at the telephoto end. The lens can be used except for APS-C also on full frame cameras and offers in a special macro mode has a maximum magnification of 0.50 x. In terms of image quality, there is the AF 70-300mm F / 4-5.6 Di LD MACRO 1: 2 highs and lows. It is good that the sharpness level is not arched (no "field curvature") and the edge of the shadow ("Vignette") is not particularly remarkable. Distortion ("distortion") are almost not available in 70 mm, and also in terms of sharpness, this focal length is the sweet spot of the lens. At other focal lengths occur significant distortions and are high f-numbers (tight sealed aperture) needed to achieve acceptable resolutions. Another weakness of the lens are the fringing ("Chromatic aberration"), which occur both in focused ("lateral chromatic aberration"), as well as in blurred image areas ("longitudinal chromatic aberration").
Although the image quality of the AF 70-300mm F / 4-5.6 Di LD MACRO 1: 2 is not just impressive, ranging from safe for most applications, and I have already seen much worse lenses at significantly higher prices. You buy this lens so certainly not because of its image quality, but the available zoom range to significantly expand with acceptable image quality - with a compact lens at a really low price.
A much more detailed report I published together with all the test shots, specifications and sample images on my homepage LensTests_de.