The Tamron 35-70mm f/3.5 lens is a small zoom lens produced in the Adaptall-II system of interchangeable lenses. I acquired this lens through KEH in Bargain condition and an adaptor off of Ebay. The lens mechanically and optically seems to be in excellent condition except for a minor problem. Cosmetically the lens is in okay condition. Most of it is excellent, but the filter ring seems to have been smacked into something pretty hard (maybe dropped) and the metal is dinged up and some of the paint was removed, however it isn’t toobad. The only mechanical issue(s) are that the lens barrel can slip forward or backward about 1/8″, though it won’t move under the weight of the lens itself, it takes a small amount of force. This effects the ease of focusing a bit, but it still isn’t hard to get bang on focus. I am unsure if this slop is a result of the damage to the front of the lens or inherent in the lens (I suspect because of the damage). The only other mechanical “problem” is that this is the earlier version of the lens and it focuses the opposite of most OM lenses, which throws me off a little bit (the Sigma 28mm f/1.8 focuses opposite as well).
The lens is a two touch lens with a pair of knurled grips on it for zooming and the barrel twists for focusing. The lens is macro focusing at 70mm with a minimum focal length of 9.8″ with a reproduction of 2.8:1! Rather amazing for a zoom lens. The lens takes a 58mm filter and is composed of 7 elements in 7 groups and is multicoated. The maximum diameter of the lens is 2.6″ and is 2.3″ in length. The total weight is a commendable 11.6oz. The f-stop range of the lens runs from 3.5 to 32 with stops at 3.5 and 4 and then every half f-stop. Some of this information is from (diagram, lens elements and weight) http://www.adaptall-2.com/
The lens is sharp at most apertures and focal lengths, it does an excellent job of macros. I acquired the lens off of KEH for ~$30 and it will be used as my standard walking around lens on my camera replacing my Vivitar 28-85mm f/3.5-4.5.