The first impression of the lens can only be described as 'massive'. Together with the K10D drags you ~ 1.5kg around with them, which can be quite difficult in the long run but. With 'reversed' hood will still fit just so in my TLZ1 photo bag. And a filter size of 77mm is not exactly small-sized.
However, the lens works by also very robust. How well the dust and splash protection works, I can not judge. The essential points are fitted with rubber seals to give a little but when changing lenses should be careful, because I already since the seal something came to meet but could also be easily again 'pushed in'. In dusty environments, I would recommend the lens briefly to clean each before changing the zoom range. Autofocus, however, is internal and therefore unproblematic.
The AHA experience comes then but when you look through the viewfinder. The whole picture is significantly clearer and sharper - especially if you're used to only the standard lens. Extremely violent is my feeling the depth of field at the 2.8-visor. On the one hand it offers the possibility very nice to play with and to achieve great effects, on the other hand are snapshots at maximum aperture a real challenge. Especially when you have to react quickly, you are caught like to the wrong point, on the one focused. Around here should work well at the camera definitely in the AF.C mode (tracking) switch.
The ultrasonic focusing works the way as desired very quietly and quickly and is a real improvement compared to the standard lens. In hectic scenes (in my case oldtimer rally) but also failed and this needs the decisive fractions of a second too long.
After the above-mentioned Internet reports I have of course tested first autofocus and photographed from the tripod at close range (30cm) with 16mm wide angle and full aperture objects with white text on a black background and could find no focussing errors or problems, so I'm assuming that the lens is fine. The image quality is excellent and the 'zooming' in the image no blurring or blooming on the text are visible.
However, I have the impression that the auto focus is not always exactly right with 'snapshots' and that the built-in Shake Reduction in the K10D with this lens works only conditionally. This is only an objective impression gained during general photography and could not be reproduced by special tests.
In addition, it seems to me also so that one (compared to the standard zoom) rather sometimes gets shown with this lens the boundaries of the image sensor of the K10D. In particular, if you shoot in the dark with available light. On the subject of darkness, one should also know that the built-in flash (in the K10D is always moderate) can completely forgotten with this lens. Alone, because due to the size of the lens, a thick shadow is cast :)
I would also like to mention that to me once the panel has blocked and could no longer be adjusted. What helped then off and on the camera. If the problem can be reproduced, which would obviously be a warranty case.
Conclusion: Compared with lenses from other manufacturers which have this performance and at ~ 1000 - are Euro, you get a but relatively inexpensive lens having very good properties for various applications and can be combined with the K10D or K20D first complete a happy dust- and splash-proof camera, otherwise there is only in the professional sector. Even those who want to take pictures in more times moist areas (tropical, sailboat, etc ...) will be grateful for the isolation and this lens hardly get around.
Even the fast and quiet autofocus and a much clearer picture (compared to the standard lens) can convince. On the big wide angle and the higher light intensity I do not want to do without. And with a minimum distance of 30cm you have almost a Macro lens.
Real friends at this lens you get in my opinion, however, only if you really know what you're doing and mostly works with manual settings. For 'snapshots' in fully automatic mode, the lens is probably only suitable and errors in the camera settings are not forgiven.
Postscript: Absolutely delighted I am since last weekend, where I worked at an event completely by candlelight. The pictures are with ISO800 yet become very good in almost complete darkness.
However, striking is the distortion in the peripheral region, when shooting indoors with 16mm wide angle ...
