Re: 2000 mm reflex lens
BH started showing the 2000 reflex a couple of months ago I believe. The last version of this lens was an M, and it was in production from 1982 to 2004. An earlier K version was produced from 1979 to 1982, and I think it was identical. Perhaps Pentax told BH that they had enough parts to assemble a couple of them. At one time BH promoted the FA 600/4 in the same manner. They're probably considered a good clearing house for limited-production specialty items. Or maybe BH found some NOS glass in the back room. It's anybody's guess. Paul Paul - Steve Desjardins desjard...@wlu.edu wrote: I was poking around the BH website and noticed that they had the Pentax 2000mm f13.5 reflex lens. First I thought it was used but it's just special order. When did that appear? -- 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.
RE: 2000 mm reflex lens
Neat. If I only had the $8700 it would be interesting addition to the kit ;-) -Original Message- From: pdml-boun...@pdml.net [mailto:pdml-boun...@pdml.net] On Behalf Of pnstenqu...@comcast.net Sent: Tuesday, June 02, 2009 1:31 PM To: Pentax-Discuss Mail List Subject: Re: 2000 mm reflex lens BH started showing the 2000 reflex a couple of months ago I believe. The last version of this lens was an M, and it was in production from 1982 to 2004. An earlier K version was produced from 1979 to 1982, and I think it was identical. Perhaps Pentax told BH that they had enough parts to assemble a couple of them. At one time BH promoted the FA 600/4 in the same manner. They're probably considered a good clearing house for limited-production specialty items. Or maybe BH found some NOS glass in the back room. It's anybody's guess. Paul Paul - Steve Desjardins desjard...@wlu.edu wrote: I was poking around the BH website and noticed that they had the Pentax 2000mm f13.5 reflex lens. First I thought it was used but it's just special order. When did that appear? -- 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. -- 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.
Re: 2000 mm reflex lens
Oh, but they've brought into the 20th century, and added a tripod collar to save the poor camera mount plate. And how can a reflex lens have 8 elements in 6 groups? My 2000mm ƒ10 Celestron 8 has a mirror, and a secondary mirror. They must have packed a few elements into the small barrel to magnify the image from a 6 design to make it 2000mm. On Jun 2, 2009, at 10:30 , pnstenqu...@comcast.net wrote: BH started showing the 2000 reflex a couple of months ago I believe. The last version of this lens was an M, and it was in production from 1982 to 2004. An earlier K version was produced from 1979 to 1982, and I think it was identical. Perhaps Pentax told BH that they had enough parts to assemble a couple of them. At one time BH promoted the FA 600/4 in the same manner. They're probably considered a good clearing house for limited-production specialty items. Or maybe BH found some NOS glass in the back room. It's anybody's guess. Paul Paul - Steve Desjardins desjard...@wlu.edu wrote: I was poking around the BH website and noticed that they had the Pentax 2000mm f13.5 reflex lens. First I thought it was used but it's just special order. When did that appear? Joseph McAllister Lots of gear, not much time http://gallery.me.com/jomac http://web.me.com/jomac/show.me/Blog/Blog.html -- 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.
Re: 2000 mm reflex lens
- Original Message - From: Joseph McAllister Subject: Re: 2000 mm reflex lens Oh, but they've brought into the 20th century, and added a tripod collar to save the poor camera mount plate. And how can a reflex lens have 8 elements in 6 groups? My 2000mm ƒ10 Celestron 8 has a mirror, and a secondary mirror. They must have packed a few elements into the small barrel to magnify the image from a 6 design to make it 2000mm. There are 5 elements behind the rear mirror. Whether they are acting as a teleconverter of sorts or are corrective elements I don't know. William Robb -- 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.
Re: 2000 mm reflex lens
On Tue, Jun 02, 2009 at 01:30:28PM -0700, Joseph McAllister scripsit: And how can a reflex lens have 8 elements in 6 groups? My 2000mm ƒ10 Celestron 8 has a mirror, and a secondary mirror. They must have packed a few elements into the small barrel to magnify the image from a 6 design to make it 2000mm. Most modern catadioptric lenses have the focusing meniscus/objective lens (depending on whether Maksutov-Cassegrain or Schmidt-Cassegrain), the primary mirror, the secondary mirror, and then a stack of regular old refractive lenses in the optical path after the primary mirror. Removing the objective and the mirrors as single element groups, that gives the remaining stack 5 elements in 3 groups, which doesn't seem unreasonable for a lens stack intended to do fine focusing. -- Graydon -- 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.
