Mitutoyo Mitutoyo 378-005 interference objective lens from Japan

Mitutoyo Mitutoyo 378-005 interference objective lens from Japan

Mitutoyo Sanfeng White Light Interference Objective WLI Plan Apo 5x

Mitutoyo Mitutoyo 378-005 interference objective lens from JapanReplace Nikon interference objective lens

Numerical aperture (NA) is an important parameter that determines the resolution, depth of focus, and image brightness of the objective lens. The numerical aperture (NA) is represented by the following formula, and the larger the value, the higher the image resolution obtained and the shallower the depth of focus. N. A.=n · Sin θ n is the refractive index of the medium between the objective lens and the sample, with n=1.0 in air. θ is the angle between the outermost light passing through the objective lens and the center of the lens (optical axis)

Field Number (F.N.=Field Number) and Actual Field of View (1): The range (diameter) of the specimen that can be observed under a microscope ● The surface area of the specimen that can be observed through an eyepiece (Berek's formula) is determined by the diameter of the eyepiece field of view aperture, and this size expressed in millimeters is called Field Number. The actual field of view is the range of the observed surface of an object that is actually magnified through an objective lens. The actual field of view can be calculated using the following formula

Depth of Focus (D.F.) refers to the range of images that can be clearly seen under a microscope, even if the focal plane moves in front or behind the imaging focus plane. The larger the numerical aperture, the shallower the depth of focus. On the contrary, the deeper the depth of focus (the smaller the numerical aperture), the wider the focusing range of the image, and even small differences can be seen at the same focal point. Due to individual differences in the regulatory ability of the human eye, there are also individual differences in the perceived depth of focus. At present, the Berry formula, which is very close to experimental results, is commonly used. Low magnification lenses such as stereomicroscopes have a deeper depth of focus, which is synonymous with the camera term depth of field