This lens is in good overall condition with some signs of use. The lens barrel shows some cosmetic marks. There is some light dust within the lens, which would not affect optical performance at all. The focus ring is in good condition. The lens mount shows signs of use.
Please note: Mark to front element, this has no discernible effect on the image rendered.
That back story is that I have the original Sigma 17-70mm lens, and it is still a great lens. I have made 30x20" prints from it. But I am thinking of replacing it with the newer Contemporary version. The addition of OS would be nice, it is a tad faster at the long end f/4 versus f/4.5, but the main reason being it has HSM. My only real complaint about the original lens is the focus is slow as it has a traditional direct drive motor.
Doing a bit of research to make sure it is worth it, that the optical quality has not deteriorated in later models or there is no a better alternative, I started reading reviews comparing it with the Canon 15-85mm lens. At twice the price of the Sigma and much slower (f/3 – 5.6 versus f/2.8 – 4) it did not change my mind that the Sigma is still the best walk around lens for me. But for that purpose, the Canon's extra range is exciting.
So being able to get a used one as described above for £150 is tempting. It would not be a main lens, but that is a price that would justify it sitting in my bag and only coming out in good light situations where I will not want to be swapping lenses, so the added range will be beneficial.
I am already planning to get the Sigma 150–600mm lens when shielding ends, and can always put off upgrading my old 17–70mm for a while anyway in favour of the Canon.
My only concern is whether in that condition, described as 'well used' would make it a good investment. It seems too cheap for a normally £680 lens, although ones in 'excellent' condition are only £230 so maybe they just do not hold their value that well? But at that price, when the Sigma lens is usually £330, it starts to seem like an alternative than a nice-to-have option. And using the same price ratio, my 'well used' Sigma as little resale value. It would only be valued at £72 before even discounting it for being several versions old.
So the 'well used' Canon, a good or bad idea?