No simple, but is worthwhile glass

The 50L is one of the lenses which I as yet have exclusive Nikon Photographer wanted to use - I bought, among other things an EOS body. I was very excited about the quality of the frame and the smooth running of the focus ring - verily L level. The autofocus is that it is a very bright lens with correspondingly large glass elements, pleasantly fast - no comparison to 85L which I also have. The lens is weather-proof and has a sealing lip on the bayonet. The weather protection must be made by filter (Canon Protection Filter 72mm) to be completed - it will survive a downpour in the right Body (I use it on a 1DsMkIII). The delivery is complete and also including GeLi -. The Objektivbeutel I find a little insufficient for such expensive lens.

Now for the more interesting - the optical properties: right at the start - I had to stop with this lens the AF per fine adjustment. Now it is open sufficiently sharp for my use (people / portrait). Who, however, the imaging performance of a macro expects this objective - and possibly still open - is sure to be disappointed. But there has character - and it has in humans far more images. On what you have to consider when the 50L is the focus shift when stopping down: the focusing by AF occurs when fully open lens - the design of this lens is such that shifts the focus point by stopping down. This is not a fault, can not by AF fine tuning or manual focusing to compensate but it is a constructive character of the lens. Most falls this phenomenon at f 2-2.8 and shorter distances.

On the web circulates as 'workaround' the use of the outer AF points. Why can compensate for the shift something / to is not precisely known - but could be due to the field curvature high open lenses.
In sum: it is a glass allowing you to work something has to in order to get warm - but when it flies, then right. Some, however, are probably not happy with it. I admit, despite the high price and the focus shifts 5 stars - simply because it is a character glass.