This photo of my photoalbum was taken in Okinawa.

The Tessar is a famous photographic lens design conceived by physicist Paul Rudolph in 1902 while he worked at the Zeiss optical company. Since Zeiss was the patent holder of the design, this type of lens is commonly known as a Zeiss Tessar. Despite common belief, the Tessar did not evolve from the 1893 Cooke triplet design by replacing the rear element with a cemented achromatic doublet. In fact, in 1890, Paul Rudolph designed the Anastigmat with two cemented doublets. Later, in 1899, he separated the doublets in the Anastigmat to produce the four-element, four-group Unar lens. In 1902 he realized that reversing the two rear elements of the Unar and returning to a cemented doublet would improve the performance of the Unar lens. He named the result "Tessar", from the Greek word τέσσερα to indicate a four-element design. A Tessar comprises four elements in three groups, one positive crown glass element on the front, one negative flint glass element at the center and a negative plano-concave flint glass element cemented with a positive convex crown glass element at the rear. Early Tessar designs allowed a maximum aperture of f/6.3. Later development allowed an aperture of f/4.5 by 1917, while further improvements with lanthanum glass allowed an aperture of f/3.5. Later evolution of the Tessar gave a maximum aperture of f/2.8, but the picture quality attained at full aperture from those lenses is significantly inferior to that of a f/3.5 Tessar. The Tessar design patent was held by Zeiss for two decades, though the design was licensed to Bausch & Lomb in the United States and to Krauss in France.

Most contemporary lenses are available for Nikon, Canon, Minolta/Sony, and Pentax mounts. It is rumoured that Tamron will start producing lenses for the Olympus/Panasonic Four Thirds mount in early 2008, and that they will be in retail shops by the Summer of the same year. An AF55-200mm Di II LD in the Four Thirds mount was recently spotted at Tamron's development offices being used on an Olympus E-400 digital SLR. It was originally believed that the source of this information was incorrect, and that the person using the Olympus E-400 had simply got a lens of a different lens mount, and was using some kind of adapter ring to mount the lens onto the camera body. However, it has been discovered that the information was indeed correct in the first place, and a selection of Tamron prototype Four Thirds lenses exists, if only in the testing stages. To this date, Tamron have denied any involvement in becoming a member of the Four Thirds System movement, and many believe this is due to the heavy involvement of Sony, who are are major player in Tamron. However, Sony have absolutely no control over what Tamron produce and sell as a company.