Darren, You might want to visit the PDML archives as I remember this issue was discussed a bit, earlier.
Relatively modern Pentax lenses "inform" the body about their identity. Bojidar Dimitrov's site can be of help for this, I think. The camera firmware includes a database of all those lenses. The adjustment will be saved for that particular lens (if you select that option). Since Pentax does not openly support other K-mount lens makers, their lenses are not in the database. Still, they usually (most of the time) find ways to declare an (albeit false) identity to the body. There is nothing you can do about these. There is no consensus on the optimal adjustment for zooms. One view (which I share) is to select a mid-range focal length for adjustment. The other view is to select the focal length you would be using most. I am sure there are others who may select to optimize the focussing for one of the extremes (probably the tele end). My K10D needed extreme values to work with some Pentax lenses. Now I understand that the body needed calibration. My later bodies were much better. Small adjustments were enough for K20D and even smaller for K5. I believe if you consistently need to add the same value for most or all of your lenses, you may as well consider servicing the body. Bulent --------------------------------------------------------------------- http://patoloji.gen.tr http://celasun.wordpress.com/ http://www.flickr.com/photos/bc_the_path/ http://photo.net/photodb/user?user_id=2226822 http://www.pentaxphotogallery.com/artists/bulentcelasun 2015-02-10 15:42 GMT+02:00 Darren Addy <[email protected]>: > So I've yet to perform any sort of AF adjustment on any of my cameras, > but I'm curious to see how my various AF lenses perform in this > regard. If you are in the same boat, here are a couple of links - the > first showing/explaining the concept: > http://vimeo.com/lensalign > And the 2nd showing you how to make a LensAlign tool for around $10. > http://www.ahfairley.com/Tutorials/LensAlign/FocusTool.htm > > I'm more than a little fuzzy about how the camera knows/remembers what > lens is on the camera. I'm guessing that it somehow records some sort > of I.D. from the lens when you perform the AF adjustment setting, but > I seem to recall reading that some lenses "report" (or are read by the > camera) as a different lens. Can anybody explain how that works or > point me to a page that explains it? Also, I'm assuming that this > works with third party AF lenses like my Sigma EXs? I think the most > critical lens to do this with is my Bigma. > > Also, on a zoom with a big range, like the 50-500mm, do you recommend > doing the align at the longest end or somewhere nearer the middle of > the range? Or does it make a difference. (I don't think it SHOULD, if > the lens is put together correctly, but...) > > Thanks in advance for any guidance or explanation. > > -- > Life is too short to put up with bad bokeh. > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
