Hi Pål, Pål Audun Jensen wrote:
> I've not noticed similar behavior with the MZ-S and the 43 Limited, but > then I never use AF with the 43mm. > Is this problem constant? Pretty much - occasionally it appears to focus correctly, but only in the near field. It is always quite noticeable off in the far distance. > That is, is it always off? The MZ-S may plays > tricks on you dependent on how it's programmed; if AF fails it may use > the AF sensor beside the one you're using to achieve focus. Then it > ficuses on something else than you assume. Do a test where you lock a > sensor. I have tried the camera with only the central, lower sensor activated, and selectively with some of the other sensors but get the same behaviour consistenly. I have also switched off the custom function which switches to another sensor when focus cannot be achieved. > The lens do communicate with the camera telling it where it is on the > helicoid and the camera use this information to achieve correct focus. > If the lens is off somehow, it's possible that AF will not work as > intended. This is what I suspect in this case, but I observed the same thing with the second 43mm lens I tried in another shop which prompted my concern that this might be a general issue with this lens. > BTW I'm really not sure any AF system is precise enough to focus 1,9 + > lenses accurately. At least manual focusing is more precise. Well, I have a Contax AX which has this back-focussing mechanism and it has no trouble focussing with pin-sharp accuracy with my 50mm f1.4 Planar. This camera is equipped with split image and microprism focussing screen so it is very easy to see how precisely it can do its job. The AF on the Contax is not by any stretch of the imagination state-of-the art and although it achieves focus by a very different route I would expect a modern AF camera to be able to do as good a job in terms of accuracy and substantially better in terms of sensitivity and speed (in these latter two areas the MZ-S certainly excels). I do not buy into the philosophy that AF SLR cameras cannot focus accurately enough. If this is true then the whole concept of AF is a massive con. Why do Canon market a 50mm f1.0 lens if an EOS is incapable of focussing it accurately? Why does Pentax market 50mm f1.4 AF lenses if you can only focus them with any precision manually? Why market the Limited series of AF lenses, widely lauded as some of the finest 35mm lenses in production, if the cameras on which you mount them are incapable of focussing them correctly. It has occured to me that the reason the 28-70 zoom appears to be spot on is the f4 maximum aperture disguising the fact that the focus is off. But I have looked very carefully to see whether I can correct the focus by switching to manual but so far it always seems to get it right. And more importantly, it will focus to infinity, unlike the 43 which never goes much beyond the 8m mark. I would be very interested to try out my new camera with a selection of other fast Pentax AF lenses but unfortunately do not have these at my disposal (and neither do any of the camera shops within a 50 mile radius of York!!) which is why I had to travel to London to buy the camera in the first place. Thanks for your thoughts! Best regards Martin - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
