2/19/2023 0 Comments Big aperture nikon zoom lens![]() A large aperture wide angle lens comprising a first lens group with a negative refractive power, a second lens group with a positive refractive power, a third lens group with a negative refractive power, and a fourth lens group with a positive refractive power arranged in the order from an object side, wherein for focusing on a near object from infinity said first lens group is fixed with respect to an image surface, and said second, third, and fourth lens groups are moved along an optical axis thereof toward said object.Ä¥. Where f 1 is a focal length of said first lens group, f 3 a focal length of said third lens group, f a focal length of overall lens system, D 1,2 an air space between the first lens group and the second lens group at the infinity focus, and D 2,3 an air space between the second lens group and the third lens group at the infinity focus.Ĥ. An inverse telephoto large aperture wide angle lens according to claim 2, wherein the following conditions are further satisfied: -4<-2 (3) -3<-1.2 (4) 0.35<0.65 (5) 0.35<0.5, (6) ![]() ![]() Where Îd 2 represents an amount of movement for focusing of said second lens group with respect to an infinity focus, Îd 3 an amount of movement for focusing of said third lens group with respect to the infinity focus, and Îd 4 an amount of movement for focusing of said fourth lens group with respect to the infinity focus.Ä£. An inverse telephoto large aperture wide angle lens according to claim 1, wherein the following conditions are satisfied for movement for focusing of said second, third, and fourth lens groups moved on the optical axis: Îd 2 =Îd 4 (1) O<Îd 3 /Îd 2 <1.3, (2) An inverse telephoto large aperture wide angle lens comprising a first lens group with a negative refractive power, a second lens group with a positive refractive power, a stop, a third lens group with a negative refractive power, and a fourth lens group with a positive refractive power arranged in the order from an object side, wherein for focusing on a near object from infinity said first lens group is fixed with respect to an image surface, and said second, third, and fourth lens groups are moved along an optical axis thereof toward said object such that a space between said first lens group and said second lens group and a space between said second lens group and said third lens group decrease, but a space between said third lens group and said fourth lens group increases.Ä¢. Photographing using prime lenses with large apertures also means you can get a shallow depth of field which is useful for portraiture where you might want a softer or blurred background (also known as bokeh).1. This is an advantage when shooting in low light conditions as it will increase the possibility of hand holding the camera and freezing the subject without shake or blur caused by the longer exposures. Prime lenses also tend to have a larger maximum aperture (f/1.4 to f/2.8). The main advantages of prime lenses or fixed focal length lenses are their size and weight as well as their maximum aperture or f/stop. Prime lenses tend to be more compact and lightweight than zoom lenses. ![]() They are ideal when you are photographing a variety of subjects such as landscapes and portraits, and you just want one lens for both situations. Using a zoom lens also reduces the number of times you need to change the lens which saves time and limits the possibility of getting dust in the camera's mirror box or on the sensor. ![]() Zoom Lens BenefitsThe advantage of a zoom lens is versatility. Prime lenses have a fixed focal length and zoom lenses have variable focal lengths. There are two types of lenses-prime and zoom. ![]()
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