Measuring Loupe, Peak Lupe 1999. Magnification 7x

The optical system used in this loupe is not conventional, but rather “telecentric,” which means that a small aperture at the focal point of the lens system allows for the measurement of three-dimensional objects such as spheres and cylinders, in addition to the length and width of flat objects, without parallax error. The telecentric Peak Loupe measuring loupe 1999 is essentially equivalent to an expensive profile projector. The lens system, consisting of three elements in two groups, has been specifically developed for these purposes.

To use this loupe, the distance between the scale and the lens system must first be adjusted by turning a knurled outer tube until the scale is clearly visible through the aperture with the largest diameter (3 mm), which can be adjusted using the rotating ring on the tip of the loupe. Then, place the loupe on the object to be measured so that the measuring scale is in contact with it, and read the length on the scale. This scale is divided into increments of 0.1 mm over a length of 20 mm, allowing the length of an object to be read with an error of less than 0.03 mm. When measuring three-dimensional objects, the aperture should be set to the smallest diameter (1 mm) or, preferably, use one with a 0.5 mm wide slit. The slit should be perpendicular to the line whose length is to be measured. Even in this case, parts of the object not in contact with the scale may appear blurred because they are not perfectly focused. No errors will occur when measuring length as long as the center distance between the unfocused images is measured, since the reduced brightness in the images resulting from the small aperture is compensated by the higher illumination of the object, which is a characteristic of the telecentric system.