Hi Sam, IMO you'd be better off with PK tubes as they transmit aperture, lens data and in some rare instances even AF (the Kenko Uniplus Pz-AF 25 mm, also sold under Soligor and Bower (IIRC) brand). There is also a helical, i.e. adjustable in length, extension tube from Pentax and then there are also bellows which do much the same as an adjustable extension tube, some (Novoflex et al.) even transmit aperture. Generally speaking, an extension tube will move a lens farther away from the sensor/film plane, thus causing it to lose infinity focus in most cases and at the same time increasing its macro abilities. This works well with fast primes but also with other lenses. Another neat trick is to reverse a lens by putting a K mount adaptor on the filter thread. Any questions, feel free to ask. I'm also selling a bunch of this stuff so feel free to inquire about that, too. Cheers Ecke
2010/7/19 Sam L <samthegr...@gmail.com>: > Hi all > > I was perusing the pentax forum marketplace and saw an add for pentax > m42 extension tubes for $15. > They seem to include 12, 20, 36mm. > > Here's a photo: > http://bkr.smugmug.com/Other/PhotoGear/11652557_WLPQY#821679568_6HGn4-A-LB > > I am clueluess about extension tubes but have heard plenty of people > say they use them for doing macro work. > I'd like to have the ability to play around and do some macro stuff. > Is this an appropriate set? Good price? Are there limitations I > should be aware of? > > I'll be mounting them to my k-x via the pentax m42 adapter. Someday > maybe I'll mount them to a spotmatic. > Would I be way better off getting a set up k-mount tubes? > > Thanks! > Sam > > -- > 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. > -- 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.
