Sigma Patents 24mm f/1.4 DG HS ART
Sigma is continuing to revamp their lens lineup and we can exclusively reveal a patent for a planned 24mm f/1.4 DG HSM ART lens. Below are some given specifications for the lens, although as is often the case with lens design patents, there are multiple versions of the optical formulae specified in the full filing. It’s no secret that brands test various versions of lenses, so these marginally different designs are often covered under one patent. This patent covers five versions of a 24mm f/1.4 design.
PROBLEM TO BE SOLVED: To provide a large-aperture optical system that is capable of providing good image quality over an entire screen by correcting aberrations well and is compact enough to be coupled to average camera bodies such as those of SLR cameras.
SOLUTION: An optical system comprises a first lens group having positive or negative refractive power, and a second lens group having positive refractive power in order from the object side to the image side, where the first lens group has a meniscus lens L1 having a convex surface on the object side and negative refractive power, one or more lenses having positive refractive power, and one or more lenses having negative refractive power, and the second lens group comprises a front second group having positive refractive power and a rear second group having positive refractive power in order from the object side to the image side. When shifting focus from an object at infinity to an object at a short distance, the second lens group moves toward the object side. The optical system satisfies predefined conditional expressions.
- Date of publication of application 21.01.2016
- INF 248mm
- Focal distance 24.65 24.99
- F number 1.47 1.60
- All the field angle 2omega 83.38 79.42
- Image height Y 21.63 21.63
- Whole length of the lens 132.60 132.60