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Achromatic objective lens, type F

Year/Period

1910-1920

Maker

ZEISS

Country

Germany

Signature

Carl Zeiss / Jena [in logo] / 7423 // F / 1.8 mm  n.A. 0.9 / D 0.17
Sleeve: Carl Zeiss / Jena [in logo] / F

Category

Accessories microscopy

Subcategory

Optical components

Optical 2

Achromatic

Size of the box (h x w x d)

sleeve: h 5.2 × ø 2.6 cm

Size of the instrument (h x w x d)

h 3.7 × ø 1.5 cm

Donated by

J.W. van Eijk, Zoetermeer, the Netherlands

Inventory number

SM 378

Description

In a brass sleeve with screw cap. The sleeve is signed with the Zeiss logo, and an ‘F’.

The ‘F’ lens was manufactured in two versions, one without a correction collar (this one) and one with a correction collar (see SM 36).

The lens contains a fluorspar (calcium fluoride) lens, which makes it possible to correct the chromatic aberration of the lens better than in a normal achromatic lens. The result is that the lens is very sensitive to variations in the thickness of the cover glass. If it is not exactly the indicated 0.17 mm, the spherical aberration increases.