LensFever

This is a 6 elements in 4 groups enlarger made by Nikon since the mid-50s. The design of this lens is pretty uncommon: the front part is a 1/2 double gauss while the rear part is a 1/2 plasmat.The reason for such design is mentioned on Nikon website: During development of the lens, a German optical manufacturer secured the patent for its basic design. Nikon (formerly Nippon Kogaku K.K.) was forced to incorporate methods that did not violate this patent into its design. There were numerous restrictions to overcome before Nikon could complete its optical system. At wide open, the lens is not as sharp as I expected. Stopping it down to F4, the overall contrast is improved significantly. Here is a sample taken 2-3 meters apart at wide open and at F4. EL-Nikkor 50mm f/2.8 @F2.8 EL-Nikkor 50mm f/2.8 @F4 Since this lens features straight aperture blades, it is expected the sunstar will be nicely defined when stopped down. The lens also works well as a landscape lens when stopped down to F...

This is a 6 elements in 4 groups double Gauss enlarger made by Fuji Photo Optical since the mid-80s. Let’s see how it performs on a Sony A7RII. The lens claimed to be having corner to corner sharpness by Fuji. Here is a sample taken 2-3 meters apart. It seems the claim is true: the low left corner is pretty decent at wide open. When stopped down to about f/5.6, it shows pretty decent performance as a landscape lens. Since this lens features straight aperture blades, it is expected the sunstars will be nicely defined when stopped down.  This lens is well-corrected for spherical aberration. There are minor bright edges on the rear bokeh on the samples here, which suggests the lens is slightly over-corrected when used at low image magnification. Here are some samples taken at medium distance. Although this lens are coated with Electron Beam Coating, there will be some venting flares on the photos due to light leak on the lens mount. Since this lens is not designed to use in outdoor, a...

Table Of Contents ✓ Introduction Leica's first Elmar 9cm (90mm) f/4.0 was introduced in 1930. The lens construction was very similar to that of the Zeiss Tessar, with the main difference being that the Elmar had the aperture positioned in front of the second lens element. After several cosmetic changes, the optics of the popular Elmar 90mm lens remained unchanged until the early 1960s. In 1962, a new version of the Elmar 90/4.0 was released, designed by Walter Mandler in Canada using newly invented rare-earth glass, which elevated the performance of this classic lens to another level. Lens Versions There is only one version. It comes with either a Leica M mount (11830) or a Leica screw mount (11830). Leica Elmar 90mm f/4.0 3-element M mount Lens Specifications Lens mount: Leica M Focal length: 90mm Aperture adjustment: f/4.0–f/22 (with half-stop clicks) Number of aperture blades: 10 Minimum focus distance: 1 meter Filter size: E39 Hood: IUFOO or 12575 Weight: ~220g Leitz Sales...