If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#61
|
|||
|
|||
What's the "leica look"?
http://patents.oncloud8.com/?pns=US3915558;US4136931
US3915558 High power wide-angle lens GLATZEL ERHARD A wide-angle lens whose back focus (for remote objects at infinity) is greater than 85 percent of the equivalent focal length of the entire lens assembly, and whose relative aperture is between f/1.8 and f/1.2, with an exceptionally high photographic performance and particularly low residual aberrations of high order over an angular field of view of more than 60 DEG . Rules or conditions are stated which, if followed, will enable the production of lenses having these desirable characteristics. Eight specific examples are given. Published Oct 28, 1975 US4136931 High speed wide angle lens system GLATZEL ERHARD A high speed wide angle lens system of the same general kind disclosed in Glatzel, U.S. Pat. No. 3,915,558, but with a slightly larger aperture and with improved image formation. While the lens formation of the U.S. Pat. No. 3,915,558 starts with two negative components, followed by a positive component, a meniscus, two negative components and two positive components in the rear part, the improved performance of the present invention is achieved by such a modification which enforces the positive power of the rear part of the lens. For this purpose the rear part is made to consist of three positive components (VII, VIII, IX) which are designed in such a way that the quotient of the sum of the surface powers of the air lenses between the three rear positive components SIGMA phi delta divided by the refractive power ( phi +EO) of the air lens between the two positive components of the front part of the lens (III, IV) lies between a disclosed upper and lower limit and that in addition to this rule the paraxial surface power sum of the second-last component (VIII) also is within disclosed limits times the paraxial surface power sum of the third-last component (VII). Eight specific examples are given to illustrate the validity of the disclosed conditions and rules. Published Jan 30, 1979 (brian) wrote in message om... TP wrote in message . .. Chris Loffredo wrote: You mention "developed": How are newer ones different from older ones? Are there any particular moments when the design was changed? AFAIK they were first made for the Contarex (late '50s early '60s) and havn't changed significantly since. They have been around for much longer than that. The basic Zeiss designs have been developed over the course of the last ~100 years. Vaguely true for the 85/1.4, but the 35/1.4 dates to design work done by Glatzel in the 1970s (see U.S. Patents 3,915,558 and 4,136,931) and bears no resemblence to any century-old designs. Also, I doubt that these lenses were particularly expensive to design since it should not have taken more than a few man-months to complete. Today it would be possible to achieve equal or better results in a week or so. Brian www.caldwellphotographic.com |
#62
|
|||
|
|||
What's the "leica look"?
While the "Planar" scheme was designed in 1896, I don't think it was
originally opened to f/1.4... ; ) The Distagon has to be much more recent: Retrofocus wide-angles were invented by Angenieux in 1950. I tried searching for more accurate information, but no luck. Only info was that at least the 85 f/1.4 was first made for the Contarex. Chris brian wrote: TP wrote in message . .. Chris Loffredo wrote: You mention "developed": How are newer ones different from older ones? Are there any particular moments when the design was changed? AFAIK they were first made for the Contarex (late '50s early '60s) and havn't changed significantly since. They have been around for much longer than that. The basic Zeiss designs have been developed over the course of the last ~100 years. Vaguely true for the 85/1.4, but the 35/1.4 dates to design work done by Glatzel in the 1970s (see U.S. Patents 3,915,558 and 4,136,931) and bears no resemblence to any century-old designs. Also, I doubt that these lenses were particularly expensive to design since it should not have taken more than a few man-months to complete. Today it would be possible to achieve equal or better results in a week or so. Brian www.caldwellphotographic.com |
#63
|
|||
|
|||
What's the "leica look"?
Chris Loffredo wrote in message ...
While the "Planar" scheme was designed in 1896, I don't think it was originally opened to f/1.4... ; ) Very true. The double-Gauss type was first developed at Zeiss, but was then forgotten until Horace Lee in England developed it into a true high-speed design. The Distagon has to be much more recent: Retrofocus wide-angles were invented by Angenieux in 1950. The name may have been invented in the 1950's, but the design type appeared decades earlier. Interestingly enough, the earliest reversed telephoto design I'm aware of is a Zeiss design (Albert Konig) dating to about 1913 (U.S. Patent 1,085,868), but it only covered a very narrow field of view and has little in common with true wide-angle retrofocus designs. Horace Lee (again) designed a very modern-looking wide angle reversed telephoto around 1930 (U.S. Patent 1,955,590). I tried searching for more accurate information, but no luck. Only info was that at least the 85 f/1.4 was first made for the Contarex. Chris |
#64
|
|||
|
|||
Leica Flamboasting Held to Standard of Proof
TP wrote in message news:
snip Both these lenses (35mm f/1.4 and 85mm f/1.4) are among the best developed optics you will find today. The importance of these focal lengths to photojournalists and portrait photographers means that large amounts of time and money have been invested in their design, and the lenses are simply superb. It is a pity that Nikon's 35mm f/1.4 falls so far short of the performance of the Carl Zeiss (and Leica) equivalent(s). Can you provide some test results to substantiate this? Frankly, I am skeptical of claims of German optical supremacy anytime after 1955 or so, but proof is proof. (Neither Carl Zeiss nor Leica are big contractors to Panavision, for one thing: Panavision optics are mostly from Japan or Switzerland, but not exclusively.) |
#65
|
|||
|
|||
Leica Flamboasting Held to Standard of Proof
|
#66
|
|||
|
|||
Leica Flamboasting Held to Standard of Proof
Panavision? WTF? Doesn't ELCAN (the old Leitz Canada) make some of their lenses? At one time they did. I think they were dropped for various issues. |
#67
|
|||
|
|||
Leica Flamboasting Held to Standard of Proof
|
#68
|
|||
|
|||
What's the "leica look"?
TP wrote in
: Of course a personal web site would appear **absolutely essential** to anyone on an ego trip, like yourself. Tony, why did you post your poor snapshots at ShutterCity? Why did you remove them? |
#69
|
|||
|
|||
What's the "leica look"?
Magnus W wrote:
TP wrote in : Of course a personal web site would appear **absolutely essential** to anyone on an ego trip, like yourself. Tony, why did you post your poor snapshots at ShutterCity? Why did you remove them? Tsk, tsk, Magnus. How dare you impugn the reputation of TP, Lord Master Photographer. TP is *above* showing his photography and need only claim to have any acceptable results at a rate of 50 rolls of film per average *week*. -- --e-meil: there's no such thing as a FreeLunch.-- |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
LEICA / Panasonic -- The Real Deal?? | David Kilpatrick | Digital Photography | 0 | June 23rd 04 10:38 PM |
Leica Digital M Body - LEAK | Jeb Sebastian | Film & Labs | 15 | May 30th 04 04:52 PM |
Ilford Pan F+ | moda | In The Darkroom | 51 | April 21st 04 02:27 AM |