Archived posting to the Leica Users Group, 2001/09/04
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hi everyone, I've been doing a little research into lens comparison tests between Leica vs. other brands. I found a rather interesting American camera the Kodak Ektra... on ebay, the guy claimed the following: 35mm Ektar for Ektra..sharper than Summaron!! Item # 1271594478 "This 35mm Ektar f3.3 # E0287 is in superb condition. Scarcely different from its condition after assembly in Rochester New York nearly fifty years ago!! Flawless glass, smooth focus and aperture control. The range finder cam zeros exactly at the infinity focus setting with a properly calibrated Kodak Ektra body. The lens' date of manufacture is 1946. Kodak's lens serial number encryption was "CAMEROCITY" equaling respectively....1234567890. EO = 46 = 1946. Considering the year of this lens' introduction (1941) few Ektra collectors realize its complexity and sophistication. It is because historical records on Kodak Ektra are so scarce. I have recently discovered this lens is a five element, three group modified Heliar type (see document photo). It is closely related to the design of the renowned 100mm Ektar of the Kodak Medalist. I have taken the time to test this lenses against the 6 element Leitz 35mm Summaron f/3.5 released in 1946. Amazingly, the Ektar (in two different examples EO287 and EY171) had substantially higher edge resolving power, both at full aperture and f/11 compared to the 35mm Summaron!! The color reproduction was more favorable as well. Center sharpness was slightly higher on the Ektar but very close with Summaron. Leitz had tried adding 2 more elements to improve the performance over its predecessor, the 4 element 35mm Elmar of 1930, but perhaps hadn't yet derived the same successful high index, low dispersion glass formulas Kodak had pioneered in 1939. (First used in the Aero-Ektars and 100mm f3.5 Ektar on Medalist used during WWII..see document scan). Interestingly Leitz did not formally advertise rare earth glass till the 5cm Summicron of 1953!!! This is all described in a copy of the RARE Kodak literature on Ektars I recently uncovered. This SIGNIFICANT new information on Kodak optical technology will certainly add to the already great stature of the Ektra camera and its optics. You get a copy with this auction!! It includes interesting information on the Ektra shutter and range finder as well. Aluminum lens carrying can has some scratches. International bidders welcome. Guaranteed as described. Bidder pays actual shipping. PayPal accepted." and also 50mm f1.9 Ektar for Ektra ...7 elements Item # 1271597354 "This 50mm f1.9 Ektar for Kodak Ektra has remarkably clean glass, nearly perfect. The focus and aperture are smooth. The range finder cam comes to exactly the infinity setting on a properly calibrated Kodak Ektra body. The barrel shows some wear. All number scales are clearly visible. Few Ektra collectors realize this lens' complexity and sophistication. It is because historical records on the Kodak Ektra camera are so scarce. I have recently discovered this lens is a full 7 element, 4 group design. This equals the number of elements of the Leitz 5cm Summitar of 1939. (See document photos) But this lens is certainly NOT a Summitar copy. It is a unique Kodak 7 element design employing two special doublets prior to the aperture, another doublet and singlet behind. Each special doublet is comprised of a plano-convex and plano-concave element. By leaving one surface flat (plano) the Ektar elements could be ground to better thickness precision than the elements in the 5cm Summitar (doublets comprised of individual elements with doubly curved surfaces rather than one flat and one curved surface). This is important in a seven element lens, since these cumulative thickness errors may cause the assembled lens to deviate substantially from its theoretical calculated performance. In comparison, one also notes the tapering of the rear elements on the Summitar necessitated by the narrow Leica screw lens flange. By comparison the Ektra's monumental breech mount allowed much greater filling angle from the comparatively large rear element. Most significantly, it was Kodak , not Leitz, who had first pioneered high index, low dispersion glass in 1939 using tantalum, lanthanum, and tungsten. Aero Ektars and 100mm f3.5 Ektar on Medalist used it during WWII. Ektars for the Ektra employed this type of glass also! The exact formulas were a closely guarded secret. Leitz did not formally advertise rare earth lanthanum glass till the Summicron of 1953!!!... although rare prototypes labeled Summitar (*) had surfaced in 1951. A further amazing fact is Kodak began coating its Ektar lenses for the Ektra in the initial production in 1941. They had used a process they referred to as "Lumenization" since 1938!! From the outset Kodak had a sophisticated understanding of alternating each coating thickness to achieve alternating "blue" and "gold" coating layers through the lens. This lens displays the alternation. A similar technique is still in use today to retain neutral color balance for multicoated lenses. Interestingly, the 5cm Summitar was not coated till November 1945 and Leitz did not alternate "blue" and "gold" coatings like Kodak so the lens' net color transmission is slightly yellow (blue light reflected back by Leitz coating). Many of these interesting facts are described in a copy of the rare Kodak literature on Ektars I recently uncovered. This is really SIGNIFICANT new information on Kodak optical technology and will certainly ADD to the already great stature of the Ektra camera and its optics. It includes interesting information on the Ektra shutter and military style Ektra range finder as well. You get a copy with this auction!! You also get a copy of the Ektra camera instructions. Of course the ACTUAL pictures a lens takes is the most important thing. Of all the many 50mm lenses I have ever used, I prefer the bo-keh properties (quality of out of focus part of image) of the 50mm Ektar the best. At full aperture these lenses renders beautiful negatives and high speed Ektachrome slides, with very good central sharpness. By f4.5 the lens is razor sharp to the edges. The original aluminum lens carrying can (not shown)IS INCLUDED WITH THE AUCTION. Lens can is fairly nice condition with only a few scratches. Cover of can doesn't close. Guaranteed as described. International bidders welcome. Bidder pays actual shipping. PayPal accepted" So guys, what do you think about the relative comparison between the Americans' ability vs. the German's ability to produce the highest quality optical lens during the 1940's? I am not technically proficient so I can't comment about lens tests this guy claims to have performed. Is it believable that Kodak could have done a much better optical job than Leica did? sincerely, Alfie