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Elmar lenses have a maximum aperture ranging between f/2.8 and f/4. Current Elmar lenses have a maximum aperture of f/3.8 or f/4, as in the Elmar-M 24 mm f/3.8 and Tri-Elmar-M 16-18-21 mm f/4. [ 1 ] The term Elmar is sometimes combined with: Super, Tele, APO, Macro or Vario.
A triplet lens A Steinheil triplet telescope eyepiece. The three lenses may be cemented together, as in the Steinheil triplet (optimized for finite conjugate ratio) or the Hastings triplet (optimized for infinite conjugate ratio). [2] Or a triplet may be designed with three spaced glasses, as in the Cooke triplet. The former has the advantage ...
The Leica Vario-Elmarit-SL 24-90mm F2.8-4 ASPH is an interchangeable standard zoom lens for Leica L mount, announced by Leica on October 20, 2015. [1]A review in PCMag UK praised the lens for its sharpness, low distortion and weatherproof, optically stabilised design, while also drawing attention to its vignetting of up to 5.5 stops at 24mm.
These are called "un-cemented", "air-spaced" or "broken contact" doublets. [4] A sub-type of air-spaced doublet is the dialyte, a design where elements are widely spaced to save on the amount of glass used or where the elements cannot be cemented because they have strongly dissimilar curvatures. [5]
The Canon EF 28–90mm f / 4–5.6 is a full frame SLR zoom lens, also often included as a kit lens with Canon EOS film cameras. The maximum aperture is f / 4 at 28mm, reducing to f / 5.6 at 90mm. When set to 90mm, this will create a moderate amount of background blur for portrait photography.
The front element of the Tessar can be replaced to make a long-focus or wide-angle lens. In 1957 Carl Zeiss offered the long-focus Pro Tessar 115 mm f/4 and 85 mm f/4, and the wide-angle Pro Tessar 35 mm f/3,2 for use on the central-shutter SLR Zeiss Ikon Contaflex Super B cameras.
The CN 90 F4 (French: CanoN de 90 millimètres Modèle F4; English: 90 millimeters gun F4 Model), also marketed under the name of Super 90, is a French rifled 90 mm tank gun produced by Giat Industries.
The Cooke triplet is a photographic lens designed and patented in 1893 by Dennis Taylor who was employed as chief engineer by T. Cooke & Sons of York. It was the first lens system that allowed the elimination of most of the optical distortion or aberration at the outer edge of the image.