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Lens Cell Cleaning
"Thor Lancelot Simon" wrote
The Schneider web site says they made the large-format Xenars until the mid 1990s (this is a surprise to me). I wonder if the later ones were any better. If the mid 80's sample I had was anything to go by the later LF Xenars were every bit as horrible as Schneider's earlier output. Quality of Angulons was probably worse, but some rather good samples did manage to escape the factory. -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.darkroomautomation.com/da-main.htm n o lindan at ix dot netcom dot com |
Lens Cell Cleaning
On 2/18/2011 5:15 PM, Donn Cave wrote:
Quoth (Thor Lancelot Simon): ... | On the other hand, maybe it's not "uncharacteristic". Wollensak made | some awful Tessar lenses and so did a few others. Maybe Richard knows: | is there something about the Tessar design that makes is particularly | prone to manufacturing or Q/C error? I believe one way to make a Tessar awful is to use it for LF applications that require a larger circle than it really delivers. The xenar I am talking about looks bad on 6X9. A 135mm tessar should easily cover that sharply when stopped down. This one won't. Stephey |
Lens Cell Cleaning
"Nicholas O. Lindan" wrote in message m... "Thor Lancelot Simon" wrote The Schneider web site says they made the large-format Xenars until the mid 1990s (this is a surprise to me). I wonder if the later ones were any better. If the mid 80's sample I had was anything to go by the later LF Xenars were every bit as horrible as Schneider's earlier output. Quality of Angulons was probably worse, but some rather good samples did manage to escape the factory. -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.darkroomautomation.com/da-main.htm n o lindan at ix dot netcom dot com I have a prototype Angulon, its awful. It has severe color fringing, something a lens of this type should not have at all. My lens designer friend tell me that the prescription in the patent shows up pretty bad when set up in a lens optimization program. Later Angulons do not seem to have this problem so it must have been changed in some way. The Angulon is similar to a Dagor but uses a different order of powers in the cells. It also has some power shifted from being exactly symmetrical to improve its correction for distant objects. It should be no worse than a W.A.Dagor but it is. Originally Schneider claimed 105 degree coverage. In fact, the lens has a circle of illumination that large but the image quality beyond about 90 degrees is pretty bad. The Dagor claims 97 degees but also isn't good beyond about 90 even the WA Dagor. Modern WA lenses are much better than these things but are also much larger and heavier. My impression is that Schneider was not a quality brand before 1945 but their lenses after that were very good to excellent. However, I've checked a couple of f/4.5 or f4.7 Xenars for Speed/Crown Graphics which showed excessive something, maybe coma or maybe oblique spherical aberration leading to smearing of highlights away from the center. This is very similar to the problem with Wollensak Raptar/Optar lenses for press cameras. Even when stopped down to f/32 the marginal image is not sharp. -- -- Richard Knoppow Los Angeles, CA, USA |
Lens Cell Cleaning
"Richard Knoppow" wrote
I have a prototype Angulon, its awful. The two good samples I have had were both 'Linhoff' branded on the shutter and were late production. -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.darkroomautomation.com/da-main.htm n o lindan at ix dot netcom dot com |
Lens Cell Cleaning
On 2/21/2011 3:55 PM, Nicholas O. Lindan wrote:
"Richard wrote I have a prototype Angulon, its awful. The two good samples I have had were both 'Linhoff' branded on the shutter and were late production. The 135mm xenar I had was in a linhoff shutter too. It was abysmal.. Stephey |
Lens Cell Cleaning
In article ,
Nicholas O. Lindan wrote: "Richard Knoppow" wrote I have a prototype Angulon, its awful. The two good samples I have had were both 'Linhoff' branded on the shutter and were late production. Interesting. I had a 90mm Angulon which I would characterize as just barely acceptable -- but not truly awful like the contemporaneous 120mm Angulon I tried around the same time. Mine too said "Linhof" on the shutter. I know at some point Linhof started doing very stringent re-QA on every lens they sold. Supposedly they duplicated the entire QA setup that Rodenstock used at the end of their production line, and supposedly they did actually reject some lenses that had passed manufacturer QA (though it is not clear whether this means the manufacturer had actually tested the lenses that failed, or just a statistically significant sample of lenses from the same run). I wonder if this was because of spotty quality from one or more suppliers earlier on. -- Thor Lancelot Simon "We cannot usually in social life pursue a single value or a single moral aim, untroubled by the need to compromise with others." - H.L.A. Hart |
Lens Cell Cleaning
On 2/22/2011 11:47 AM, Thor Lancelot Simon wrote:
In articleiq6dnXcmLK1HTf_QnZ2dnUVZ_qOdnZ2d@earthlink .com, Nicholas O. wrote: "Richard wrote I have a prototype Angulon, its awful. The two good samples I have had were both 'Linhoff' branded on the shutter and were late production. Interesting. I had a 90mm Angulon which I would characterize as just barely acceptable -- but not truly awful like the contemporaneous 120mm Angulon I tried around the same time. Mine too said "Linhof" on the shutter. I know at some point Linhof started doing very stringent re-QA on every lens they sold. Supposedly they duplicated the entire QA setup that Rodenstock used at the end of their production line, and supposedly they did actually reject some lenses that had passed manufacturer QA (though it is not clear whether this means the manufacturer had actually tested the lenses that failed, or just a statistically significant sample of lenses from the same run). I wonder if this was because of spotty quality from one or more suppliers earlier on. I have heard this same thing but question this given the 135mm xenar I had, that was horrid, was in a linhof shutter. Obviously some other lens other than the original one could have been put in this shutter by someone along the way to make it appear to be a better lens than it was. I suppose seeing the linhof brand on a shutter could help "prove" it's a good sample but given the age and unknown history, it's not a fact cut in stone anymore. Stephey |
Lens Cell Cleaning
In article ,
wrote: I suppose seeing the linhof brand on a shutter could help "prove" it's a good sample but given the age and unknown history, it's not a fact cut in stone anymore. Right. At one point in the mid-90s, the Linhof factory rep for the U.S. used to very loudly hold forth here about the special Rodenstock testing machine Linhof had acquired for this purpose, etc. etc. -- but then again, he was also the Rodenstock factory rep. He didn't typically respond to questions about what might be wrong with Rodenstock's own quality control such that Linhof felt they needed to repeat it! (Of course, this was a little unfair, since Linhof did not relabel *only* Rodenstock lenses... but it was fun to yank the guy's chain.) I suspect Linhof was badly burned by questionable lenses at some point and decided on this testing program to reduce warranty costs or brand image problems. That would imply that after some point, Linhof-marked lenses were particularly good, while before that time, they may well have been particularly bad. Since for Linhof's main competitor, there were always both budget (Wollensak) and premium (Kodak) lenses available, someone having an awful experience with a Raptar was not likely to abandon the Graphic or Graflex cameras entirely. But if Linhof was getting all or most of their lenses from Schneider at some point and Schneider was churning out Xenars of poor quality -- which seems to have been the case! -- then they would need some way to escape the damage this could do their brand. -- Thor Lancelot Simon "We cannot usually in social life pursue a single value or a single moral aim, untroubled by the need to compromise with others." - H.L.A. Hart |
Lens Cell Cleaning
"Thor Lancelot Simon" wrote in message ... In article , wrote: I suppose seeing the linhof brand on a shutter could help "prove" it's a good sample but given the age and unknown history, it's not a fact cut in stone anymore. Right. At one point in the mid-90s, the Linhof factory rep for the U.S. used to very loudly hold forth here about the special Rodenstock testing machine Linhof had acquired for this purpose, etc. etc. -- but then again, he was also the Rodenstock factory rep. He didn't typically respond to questions about what might be wrong with Rodenstock's own quality control such that Linhof felt they needed to repeat it! (Of course, this was a little unfair, since Linhof did not relabel *only* Rodenstock lenses... but it was fun to yank the guy's chain.) I suspect Linhof was badly burned by questionable lenses at some point and decided on this testing program to reduce warranty costs or brand image problems. That would imply that after some point, Linhof-marked lenses were particularly good, while before that time, they may well have been particularly bad. Since for Linhof's main competitor, there were always both budget (Wollensak) and premium (Kodak) lenses available, someone having an awful experience with a Raptar was not likely to abandon the Graphic or Graflex cameras entirely. But if Linhof was getting all or most of their lenses from Schneider at some point and Schneider was churning out Xenars of poor quality -- which seems to have been the case! -- then they would need some way to escape the damage this could do their brand. -- Thor Lancelot Simon The curious thing is that Wollensak's prices were no lower than Kodak's for their "premium" lenses. I think there was some sort of design blunder made on the design for the Raptar/Optar lenses used on press cameras and the Enlarging Raptar lenses, which are also pretty bad. Kodak's Ektar lenses are uniformly excellent as are the Enlarging Ektars. Even Ilex lenses, also not cheap by any means were head and shoulders better than Wollensak. Now, another curiosity is that the Optar lenses made by Wollensak for the Series-D Graflex are excellent. A different design even though still a Tessar. They were offered as an alternative to the Ektar lenses for these cameras but the price was about the same. I think Wollensak got the reputation for being cheap because they made a lot of OEM lenses for cheap cameras. So did Ilex for that matter. Wollensak shutters OTOH are excellent and, since they use all hair-springs, can be rebuilt with new parts. -- -- Richard Knoppow Los Angeles, CA, USA |
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