Two lenses that often get confused are the 107mm f /3.7 Ektar and the 105mm f /3.7 Ektar  . Reliable sources tell me that the 107mm was one of the first Ektar designs and was in a Tessar formula, uncoated and mounted in an unsynchronized Kodak Supermatic No. 2 shutter. As compared to the Kodak Anastigmats, lateral color correction had probably been improved in the Ektar, possibly through the use of new glass compounds that Kodak was developing. This lens was produced by Kodak from about 1937 through 1940 and intended for use on 2 1/4 x 3 1/4 press cameras or as a copy lens mounted on enlarger bellows with a film back. Some of these lenses used the early all-numeric serial numbers, while later onesused serial numbers in the CAMEROSITY format. Since the production of this lens preceeds publication of the Kodak Reference Manual and Data Books, I do not have a schematic of its optical design. One site visitor who has one of these reports that the rear group appears to have the positive element next to the stop, different from the bulk of Kodak Tessar designs, but similar to reversals in rear group orders that also occurred in the 50mm f /3.5 Ektar for the Kodak Ektra  and 78mm f /3.5 Ektar   on the Kodak Chevron. Another noteable difference in these lenses is the shapes of the individual element in the rear group varies from those the more common Kodak Tessar designs.

The 105mm version   was a Heliar formula calculated by Fred Altman and was essentially the same lens used by the Kodak Medalist offered originally in 1941. The free-standing lens was originally inner coated with calcium fluroide and in the mid-1940s was coated on all surfaces with magnesium fluoride. The 105mm version was available in Supermatic shutters initially and about 1947 moved to the synchronized equivalent, the Flash Supermatic.