Bought this lens with some trepidation because of concern over SDM failures. I "needed" a lens in this range and 3rd party lens makers really didn't have what I wanted. There were reports that the SDM was remodeled in 2012 (hope that was true and not industry talk) because of the failures in both...

Excellent lens, I haven't taken it off the camera since I got it. With the Pentax K5 its just brilliant.

I bought this lens to travel in Asia where the weather is Humid and rain.. SO far I tested the lens in Sichuan province in the forest to shot panda: Rain and humidity did not affect at all the camera and the lense (the big lens hood in the end turn out to be a really good protection for the lens...

Sharpness; Colour rendition; Quality

Lens hood far to big

Helluva lens. From f3.5 and up has never let me down. Early I tried the 2.8 in unsuitable situation (hasty glamour shoots in nature etc) and was frequently underwhelmed but now I understand it better - its just brilliant.

Quality; handling; weather resistance; quick shift

SDM (always in the back of my mind)

Purchased this lens to replace a 70-200 f2.8 which I found to be heavy and difficult to handle. I use a K5 camera with grip, this lens is just perfect, balances beautifully with this camera and the 50-135 focal length is so much more useful than the previous lens.

This is an AMAZING lens... I love the wide rubberized zoom ring, which functions very smoothly and it has an internal focusing system (IF) the front element does not rotate so you can easily use a polarizer on it.

This is an AMAZING lens... I love the wide rubberized zoom ring, which functions very smoothly and it has an internal focusing system (IF) the front element does not rotate so you can easily use a polarizer on it.

Consistent Output; Durable; Easily Interchangeable; Fast / accurate auto-focus; Nice Bokeh; Rugged; Sharp Clear Photos; Strong Construction

Mediumweight

Yes, I would recommend this to a friend

Consistent Output; Durable; Easily Interchangeable; Rugged; Strong Construction

Heavy

superior optical quality. extremely fast focus on K7, even in low light.

I have had this lens for 12 months now, and to be honest, it is stunning.Now before I go further, I have had to drop a star in a couple of areas, for the following reasons.As I write, the current price for this lens is a mighty £920!

perfect portrait lens; Sharp; size against rivals; Weather sealing

price (at time of writing; slightly slow af (ish