The Ektra's Ektar lenses, like most other lenses of this period were heavily influenced by the Tessar design and were created from designs and with manufacturing technology Kodak had developed in the 30s. While the formulae used were not novel, their implementation in the Ektar line was generally excellent for the period. Quality control in the Kodak manufacturing process was considered outstanding.

The f/3.5 50mm is a standard Tessar type with four elements in three groups, with the last elements reversed in power from the original Tessar design. The f/3.5 90mm is a simplified version with three separate elements. The longest manufactured lens in the series, the f/4.5 153mm, has a double negative cemented pair behind the stop. The f/3.8 135mm uses a differently designed rear element, which may have been an original Kodak design. The f/3.5 35mm is a Heliar design by F. E. Altman of five elements in three groups, very similar to the f/3.5 100mm Ektar used on the Medalist. Apparently Kodak had planned a super tele of about 250mm, since the variable viewfinder has a setting for 254mm. Neither the glossy Ektra prospectus, published on the camera's release in 1941, nor the "Kodak Lenses" section of the Kodak Reference Manual, published originally in 1942, have any mention of this long lens, though I have heard unsubstantiated claims that there was at least one prototype. The f/1.9 50mm is a variation of the Biotar design, originally used in the f/2.0 45mm Ektar mounted on the Bantam Special. Of these lenses, the f/3.5 50mm and f/3.5 35mm are reputed to be the sharpest, with the f/1.9 50mm to have the poorest resolution and flare performance, a characteristic of most highspeed lenses of that period. All Ektra lenses attach to the body with a screw mount that locks when snug. Two keyways on the mount make lens orientation a no-brainer with the body in any position.

While Kodak had begun treating air-glass surfaces in the late 30s, I can only find documented evidence of their Lumenized coating of magnesium fluoride in lens manufacture of the late 40s. The lens section of the Kodak reference manual, printed in 1945 (second edition?) does not include Lumenized lenses, while the separate Kodak Data Book, Kodak Lenses, Shutters and Portra Lenses, 3rd Edition (1948) describes the process, but no longer includes the Ektra lenses. In his 1951 book, Lenses in Photography, Rudolf Kingslake, Director of Optical Design for Kodak, reports that calcium fluoride, as an optical coating, was first offered for commercial use in 1938, but its softness relegated it to inner surfaces. The Ektra prospectus of 1941states that "inner surfaces of the lenses are treated by a coating process that improves the clarity and brilliance of the negatives obtained." The magnesium fluoride that could be deposited on glass and which Kingslake reports "was as hard as the glass itself," was adopted in the 40s. Whether later Ektra Ektars ever had this coating is for me an open question. Most lenses that are hard-coated or 'Lumenized' will have an symbol following the lens serial number, but there are early exceptions. My assumption then must be that all Ektra Ektars were coated, but many with calcium fluoride only on inner surfaces, presenting a significant problem to restorers. I would not disassemble Ektra lenses to clean their inner surfaces; some technicians may know how to do this without damaging the coating, but I would get this specific assurance before authorizing such work and I would specifically prohibit such work when I was having maintenance work done on such lenses unless this assurance was given. More general information on Ektar lenses is available  , and from a page no longer available, but restored from Robert Monaghan's Medium format site  .

Kodak also manufactured and distributed lenses for broadcast and industrial cameras. In some cases, Television Ektanons appear to be similar to Ektra Ektars lenses but may have different lens formulae and coatings; the focusing mechanisms may also differ.