1903 Bull. U.S. Geol. Surv. No. 213. 113 The principal mines..have revealed valuable ore bodies of two great types, those which occur as lenses, roughly parallel to the bedding, and those which occur in fracture or fissure zones.

1935 Economist 21 Dec. 1283/3 Further lenses of valuable ore would be discovered in that section.

1939 Proc. Prehistoric Soc. 5 40 Towards the top of the ferruginous gravels appears a lens of non-ferruginous, grey, clayey sand.

1969 G. M. Bennison & A. E. Wright Geol. Hist. Brit. Isles vi. 128 These Lower Palaeozoic rocks occur as discontinuous outcrops or lenses in what has been termed the Meneage Crush Zone... Included lenses may be up to 1 mile in length.

1882 Photogr. at Home: its Appliances & Apparatus for Amateurs 11 A little shield covered with black velvet..occupies the place of the ordinary lens cap.

1897 Sears, Roebuck Catal. No. 104. 474/2 The front of the camera can be removed if desired and exposure made with a lens cap.

1965 Mrs. L. B. Johnson White House Diary 17 June (1970) 290 I wanted to be darned sure I didn't lose the lens cap on the camera.

1966 M. LaCour & I. T. Lathrop Photo Technol. iv. 48/2 It should seldom be necessary to clean a lens which has been protected from dust and fingerprints with a lens cap.

1952 C. B. Neblette Photogr. (ed. 5) ii. 48/1 Lens coatings are a remedial measure and do not entirely remove reflections.

1966 M. LaCour & I. T. Lathrop Photo Technol. iv. 48/2 Finger prints on the lens..are detrimental to the lens coating.

1839–47 Todd's Cycl. Anat. & Physiol. III. 769/1 The lens-eyes of insecta.

1787 E. Darwin et al. tr. C. Linnaeus et al. Families of Plants I. 16 Seeds solitary, lens-form.

1891 W. E. Woodbury Encycl. Photogr. 405 (heading) Lens screen or hood.

1908 Brit. Jrnl. Photogr. 55 245/1 The lens-hood..has recently revived, owing to the necessity of shading the lens from direct light in the case of anastigmats which possess large aperture.

1955 E. Hillary High Adventure xii. 210 I clipped on [to my camera] the lenshood and ultra-violet filter.

1968 L. A. Mannheim tr. H.-M. Brandt Photogr. Lens xv. 166 Lens hoods not only have to shield the lens against stray light, but also protect it against accidental finger marks and rain or snow.

1928 Amer. Speech 3 368 Actors who strive for the most advantageous positions are also called ‘lens lice’.

1950 J. Hall in Daily Mail 24 May Bane of the news-reel cameraman is what he calls a ‘lens louse’. They..never miss a chance of getting in front of a news-reel camera.

1951 N.Y. Herald Tribune 26 Aug. iv. 4/4 It was common to see a Leatherneck lensman wield a 45-automatic pistol in one hand and a 16-mm. camera in the other, firing both simultaneously at the enemy only a few hundred yards away.

1964 Punch 5 Aug. 183/1 He's one of the best lensmen in the business.

1972 I. Hamilton Thrill Machine vi. 27 I held back with the pen and ink men while the lensmen pushed forward to the press barricades.

1925 A. F. Collins Amateur Photographer's Handbk. iv. 61 Dirt that forms on the surfaces [of a lens] in an almost imperceptible film can usually be wiped off with a dry lens paper, which is a very soft Japanese tissue paper especially made for this purpose.

1973 Nature 27 July 233/1 Each portion [of ovary] was placed on defatted lens paper on a stainless steel mesh grid in a vitreosil dish.

1941 A. Sussman Collins's Amateur Photographer's Handbk. (rev. ed.) iii. 75 Use some dry lens tissue, or an old linen handkerchief that has been freshly laundered.

1955 S. C. Gilmour Paper 305 Lens tissue, British-made paper of very thin substance and transparent texture, resembling Japanese tissue. Long fibres, great strength for the substance, and extreme absorbency are characteristics. Used for cleaning optical and microscope lenses.

1951 R. Spottiswoode Film & its Techniques iii. 64 Camera noise readily seeps through a lens turret and tends to interfere with dialogue recording.

1963 Movie July–Aug. 26/3 Brault's insistence on leaving in blank frames as he shifts the lens turret in mid-reel occasionally gets in the way.

1971 L. B. Happé Basic Motion Pict. Technol. x. 311 A lens turret mounting is often preferred for unit lenses and is more convenient for automated operations.

1859 G. A. Sala Twice round Clock (1861) 274 If you eye him narrowly through the many-lensed lorgnette.

1892 Illustr. London News 1 Oct. 431/3 An eye lensed like a microscope, though also lensed like yours and mine.

1890 J. Cagney tr. R. von Jaksch Clin. Diagnosis i. 44 The lensless-spectroscope consists of two tubes.

1875 E. H. Knight Amer. Mech. Dict. II. 899/1 Folder,..2. A form of spectacles in which the lenses fold together for the pocket.

1927 F. B. Young Portrait of Clare 26 She brushed the dust from her skirt..her grey eyes swimming behind the lenses of her pincenez.

1965 T. Capote In Cold Blood (1966) iv. 237 Mrs. Hickock removed the spectacles she was wearing, polished the smeared lenses and resettled them on her pudgy, agreeable face.

1976 Verbatim Sept. 10/2 Both lens [sic] of my safety glasses were so scratched up they had to give me new ones.

1987 B. Moore Colour of Blood xviii. 137 He stared at this man, at the..angry eyes behind thick lenses.

1888 C. H. May tr. A. E. Fick in Arch. Ophthalmol. 17 226 If the lens fits well, the patient does not complain, has no flow of tears, and either has no injection of the ocular conjunctiva, or very little.

1938 Trans. Ophthalm. Soc. 58 120 The question of tolerance was early recognized as important when it was found that some patients could wear a lens and others not.

1962 L. Daily & R. K. Daily in M. B. Raiford Contact Lens Managem. 155 After many weeks or months of wearing the lens, the patient may complain that vision is poor.

1987 New Yorker 16 Feb. 36/2 My lenses dry up, and I take them out.

1990 C. Brayfield Prince xxii. 487 Her eyes were tired and she had taken out her lenses, so she rummaged at the back of a drawer for her old spectacles to look at them properly.

1921 G. H. Cox et al. Field Methods Petroleum Geol. 11 The effects of irregularities in sands may be considered to be of three types; those in which the sand lenses out entirely, those in which it loses its porosity, and those in which the porous sand continues but is of changing thickness.

1965 G. J. Williams Econ. Geol. N.Z. viii. 108/2 Mining went down to the 500-ft level below which the calcite bodies themselves lens out—as proved by angled diamond drill-holes.