Peter, That "secondary tier" expression of yours is bound to piss off a few folks, you Troll! Jerry "Peter K." wrote: > Todd, you are reaching with this. OK, so it does not specifically > states it was done to IMPROVE performance. It DOES state that it was > done to meet the guaranteed performance of the 75mm lens. So if we are > saying it was difficult to meet the criteria or a certain level of > performance, wouldn't that mean basically the newer design improved > things? Hence, there would have been a better chance of getting a > better performing 75mm lens. More than that I do not know. But I > cannot imagine anyone in business stating that the newer design > IMPROVED the performance because they are saying the older lenses are > not as good. As to the 5-element being used for 7 years, I do not > know. Since this was a secondary tier camera, perhaps Rollei felt it > was not necessary to change it and allowed them to better > differentiate the F model. Just my opinion on the last part. Peter > K On 1/2/06, todd belcher <todd_belcher@xxxxxxxxx> wrote: > > Actually your analysis of the text does not support your > claim that the 6 element lens was done for an increase in > performance. Nowhere in the quoted passage does it say "the > 6-element version were done to IMPROVE the performance of > the 3.5 model". It does say maintaining quality on 5 > elements was difficult. This could have been because one of > the glass types in the 5 element became expensive, or > unavailable, and thus maintaining the 5 element design with > the same performance would have been difficult. Remember the > 3.5 E came out in 1956 with the same five element lens and > it wasn't until sometime around 1963 that the six element > lens was introduced. So that means about 7 years of five > element 3.5 gauss type lenses. I cannot imagine Rollei > would allow such a long time to pass for supposedly > underperforming lenses. Therefore, the switch to 6 elements, > guaranteed the SAME (it says "served to MEET the performance > data guaranteed to Rollei") quality as the 5 element lens. > And as a bonus, it happened to cost the same as the 5 > element lens. todd On 2-Jan-06, at 3:02 PM, Peter K. > wrote: > > > OK Carlos, I have the Rollei 75 Years book, also written > > by Prochnow. On pages 140 and 141 it stated the following > > with regard to the model F: "Of course there were other > > improvements that had their share in the great success of > > the "F" models. One of these was the new, six-element > > Planar 75mm F3.5 lens which was introduced rather quietly > > with the third version of the 3.5F. Shortly after, > > Schneider followed with a 75mm Xenotar F3.5, likewise made > > up of six elements. The new optical formulas served to > > meet the performance data guaranteed to Rollei, which were > > difficult to attain with only five element. Production > > costs remained unchanged. The 80mm F2.8 Planar and Xenotar > > lenses did not have these problems and thus retained their > > five elements." So here is a book endorsed by Rollei and > > written by Prochnow where he claims the 6-element version > > were done to improve the performance of the 3.5 models and > > the interesting note is that it is clearly stated that > > PRODUCTION COSTS REMAINED UNCHANGED. This is why I stated > > this. Peter K > > On 1/2/06, Carlos Manuel Freaza <cmfreaza@xxxxxxxxxxxx > > > wrote: > > > > Excuse me Peter, I have the Rollei Report II and > > > > Prochnow does not write about resolving power > > problems > > for the five elements 3.5/75,and in his message > > to me, > > he insisted that the Planar and Xenotar six > > elements > > were cheaper to manufacture than the five > > elements and > > this was the only reason to provide the > > Rolleiflex > > with this six elements 3.5/75 Planar and > > Xenotar; > > Richard K.also suspected this economical reason > > before > > I received the message from Prochnow and the > > lens > > designer friend of Richard K also wrote about > > these > > economical reasons agreeing with Richard. > > If you see the second element for the five > > elements > > Planar 3.5/75 and the fourth element for the > > Xenotar > > 3.5/75, they are a thick glass piece, a > > divergent > > meniscus (negative lens); for the six elements > > version > > this piece or element was divided into two > > thinner > > pieces and cemented maintaining its condition of > > > > divergent meniscus and occupying the same place > > regardiong the original divergent meniscus, the > > other > > elements are identical for the five and six > > elements > > versions and then they are (the five and six > > elements) > > the same lens in practical use. > > I owned a 3.5E provided with a Planar five > > elements > > several years and it was an outstanding lens for > > > > 50x50cm enlargements.- > > > > All the best > > Carlos > > PS:Peter, if necessary, I have the question and > > the > > Prochnow's answer.- > > --- "Peter K." < peterk727@xxxxxxxxx> escribió: > > > > > Yes Carlos I know. In his book however, > > Prochnow > > > claimed, or used, the party > > > line that it was for resolving power. May > > actually > > > be a combination of the > > > two. > > > > > > Peter K > > > > > > > > > On 1/2/06, Carlos Manuel Freaza > > > <cmfreaza@xxxxxxxxxxxx > wrote: > > > > > > > > --- "Peter K." < peterk727@xxxxxxxxx> > > escribió: > > > > > >.... The 3.5 version of this > > > > > model also received a newly designed > > Planar lens > > > of > > > > > six elements, followed > > > > > by a new Schneider 3.5 Xenotar with six > > > elements. > > > > > This was allegedly to > > > > > improve the resolving power since F & H > > were of > > > the > > > > > opinion that the older > > > > > style 5-element 3.5 lenses did not live up > > to > > > > > expectations.... > > > > > Peter K > > > > > > > > According Claus Prochnow Rollei Report II > > and a > > > > message he wrote me answering my specific > > question > > > > about it, the change for a Planar and > > Xenotar > > > 3.5/75 > > > > from five elements into six elements had > > > economical > > > > reasons only, the Planar and Xenotar five > > elements > > > > 3.5/75 had a thick element very expensive to > > > > > > manufacture and then this element was > > converted > > > into > > > > two thinner elements without a real change > > for the > > > > lens general design, you can clearly see it > > > comparing > > > > both lenses five and six elements diagram . > > > > Prochnow writes in his book that the six > > elements > > > > Planar and Xenotar 3.5/75 were "cheaper" to > > > > manufacture "maintaining the lens quality" > > (in > > > other > > > > words, the five elements was at least equal > > > regarding > > > > quality). > > > > He also writes that the Planar and Xenotar > > 2.8/80 > > > have > > > > not production costs problems and then they > > were > > > > maintained without changes.- > > > > > > > > All the best > > > > Carlos > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > _ > > _________________________________________________________ > > > > > > 1GB gratis, Antivirus y Antispam > > > > Correo Yahoo!, el mejor correo web del mundo > > > > > > http://correo.yahoo.com.ar > > > > > > > > --- > > > > Rollei List > > > > > > > > - Post to rollei_list@xxxxxxxxxxxxx > > > > > > > > - Subscribe at > > rollei_list-request@xxxxxxxxxxxxx > > > with 'subscribe' > > > > in the subject field OR by logging into > > > www.freelists.org > > > > > > > > - Unsubscribe at > > rollei_list-request@xxxxxxxxxxxxx > > > with > > > > 'unsubscribe' in the subject field OR by > > logging > > > into www.freelists.org > > > > > > > > - Online, searchable archives are available > > at > > > > > > //www.freelists.org/archives/rollei_list > > > > > > > > > > > > > > > > > -- > > > Peter K > > > Ó¿Õ¬ > > > > > > > > > > > > > > > > > > > > > _ > > _________________________________________________________ > > > > 1GB gratis, Antivirus y Antispam > > Correo Yahoo!, el mejor correo web del mundo > > http://correo.yahoo.com.ar > > > > --- > > Rollei List > > > > - Post to rollei_list@xxxxxxxxxxxxx > > > > - Subscribe at rollei_list-request@xxxxxxxxxxxxx > > with 'subscribe' > > in the subject field OR by logging into > > www.freelists.org > > > > - Unsubscribe at > > rollei_list-request@xxxxxxxxxxxxx with > > 'unsubscribe' in the subject field OR by logging > > into www.freelists.org > > > > - Online, searchable archives are available at > > //www.freelists.org/archives/rollei_list > > > > > > > > > > > > -- > > Peter K > > Ó¿Õ¬ > > > > > -- > Peter K > Ó¿Õ¬ > > ---------------------------------------------------------------- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.371 / Virus Database: 267.14.10/218 - Release Date: > 01/02/2006 > >