Which Joe gave his name to ‘sloppy joes’? We look at five interesting sandwiches and their lexical origins.
1The distance between the center of a lens or curved mirror and its focus.
- ‘Varying the voltage across the lens, the researchers could change the focal length of the lens, because this alters its refractive index.’
- ‘The focal length of the lens that you use, depends on where you are in relation to the fireworks and the composition you're looking for.’
- ‘This will give a negative focal length for a convex lens of air inside water.’
- ‘The shorter the focal length of the lens, the wider the field of vision.’
- ‘Yet Stork determined the probable focal length of a concave mirror made by inverting and silvering the convex mirror shown in the painting.’
- ‘That behavior is not affected by the medium in which the light travels, so the mirror's focal length would be no different in air or water.’
- ‘In 1647 Cavalieri published an important contribution to optics when he gave the relationship between the curvature of a thin lens and its focal length.’
- ‘A double convex lens with a focal length of 50 cm is fixed in a PVC pipe about 60 cm long.’
- ‘When you increase the focal length of the lens (or decrease the film size) an apparent ‘compression’ of the image occurs.’
- ‘This produces a rounded lens with a small focal length, so the drop can focus light only to a point near itself.’
- ‘I suggest that you look at any one that has a range in the focal length of the lens.’
- ‘Long focal length lenses require less diffusion than short ones to achieve the same visual effect.’
- ‘To overcome this, we must use a large number of mirror shells and as long a focal length as possible.’
- ‘The focal length of this lens can be varied somewhat without compromising the quality of the data.’
- ‘Changing the lens's curvature changes the focal length, so that images at different distances appear in focus.’
- ‘The focal length of a lens, for example, varies depending on the colour of light that is being focused.’
- ‘Three things control how great the depth of field will be in a photograph: lens focal length, aperture, and distance from the subject.’
- ‘A dioptre is 1 divided by the focal length of the lens in centimetres.’
- ‘Our team chose two tube lenses with focal lengths that provided the necessary magnifications and fields of view.’
- ‘Telephoto lenses have focal lengths that range from about 85 mm (good for portraits) to supertelephotos' 300 mm to 600 mm or longer.’
- 1.1 The equivalent distance in a compound lens or telescope.
- ‘The magnification is simply the focal length of objective lens divided by the focal length of eyepiece.’
- ‘The higher graze angle allows a shorter focal length and also preserves the collecting area of the telescope.’
- ‘The tube of the Gregorian telescope is thus shorter than the sum of the focal lengths of the two mirrors.’
- ‘He devised numerous ways of reducing the physical size of telescopes of long focal length, and machinery with which to move them.’
- ‘One evening he was observing with a rather crude refractor (a lens telescope), with a focal length of 24 feet.’
- ‘Small phase change leads to a long focal length, which is more suitable for telescope and satellite imaging applications.’
- ‘He developed a general rule for the focal length of lenses and described a reflecting telescope.’
- ‘By changing the distance between particular lenses, you can adjust the magnification power - the focal length - of the lens as a whole.’
- ‘Huygens later went back to the study of optics and developed long focal length lenses used in ‘aerial telescopes.’’
We take a look at several popular, though confusing, punctuation marks.
From Afghanistan to Zimbabwe, discover surprising and intriguing language facts from around the globe.
The definitions of ‘buddy’ and ‘bro’ in the OED have recently been revised. We explore their history and increase in popularity.