Hi, I like this lens too, though the hunting did annoy me. I've changed over to the smaller WR version for most of my current work.
The controls do this: Clamp: as stated by others stops the lens from moving when pointing it down (or up). It puts a drag on auto focus which will lock it anyway. Use it if you need to, I normally left it off. Limit: reduces hunt by locking the lens to the macro or non macro focus range. I can't remember actually using it. MF: Turns the lens into a manual focus lens as far as the camera is concerned. This means you can use the "Trap in focus" feature where the camera is set to autofocus (the lens in manual) and keeping the shutter button depressed the camera will fire when it gets autofocus confirmation. I played with it a couple of times, but found that to get the best depth of field I needed to manually focus anyway. It's a very nice lens. Have fun. Leon On 5 December 2012 13:48, Daniel J. Matyola <danmaty...@gmail.com> wrote: > After all the great advice I received from this list on selecting a > Macro lens for my K-r (and future K-5), I made my decision. I decided > to go old school -- and cheap. > > I found a used smc Pentax FA 100mm 1:2-8 Macro for $338 including > shipping. It is certainly well built (and heavy). So far, I've only > played around with it, taking some test images hand-held. So far, It > looks really good. > > The problem: I went online to Pentax to download the manual, but they > no longer carry it. Does anyone know where I can get one. > > The reason I need the manual is the lens has two controls that I don't > really understand. They are visible in the right half of this image: > http://www.photozone.de/images/8Reviews/lenses/pentax_100_28_fa/lens.jpg > . > > From the reviews, I understand that the lens "hunts" a lot in > autofocus mode. The "focus range" control apparently alleviates that > problem, by limiting the rage of focus. I am not clear, however, how > to use the control. Also, why does this control have an "MF" setting, > when manual focus is usually selected on the camera. Is there a > difference between selecting manual focus on the lens rather than on > the camera? > > Even more mysterious -- to me -- is the "clamp" dial. What does this > do, and how? > > Any information or advice will be greatly appreciated. > > TIA, Dan > > Dan Matyola > http://www.pentaxphotogallery.com/danieljmatyola -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
