When the “ same picture ” is taken in two different format sizes from the same distance at the same f-number with lenses that give the same angle of view, and the final images ( e. g., in prints, or on a projection screen or electronic display ) are the same size,

In early lighthouses, the light source was a kerosene lamp or, earlier, an animal or vegetable oil Argand lamp, and the lenses rotated by a weight driven clockwork assembly wound by lighthouse keepers, sometimes as often as every two hours.

After the invention of the telescope Kepler set out the theoretical basis on how they worked and described an improved version, known as the Keplerian telescope, using two convex lenses to produce higher magnification.

In general, two types of lenses exist: convex lenses, which cause parallel light rays to converge, and concave lenses, which cause parallel light rays to diverge.

The electron beam, which typically has an energy ranging from 0. 2 keV to 40 keV, is focused by one or two condenser lenses to a spot about 0. 4 nm to 5 nm in diameter.

Rollei made at least two such lenses for their Rolleiflex SL-66 medium format which was a focal-plane shutter SLR.

The focal length value is not required when comparing two lenses of the same focal length ; a value of 1 can be used instead, and the other factors can be dropped as well, leaving area proportion to the reciprocal square of the f-number N.

By combining more than two lenses of different composition, the degree of correction can be further increased, as seen in an apochromatic lens or apochromat.

These hybridized glasses have a very low level of optical dispersion ; only two compiled lenses made of these substances can yield a high level of correction.

* 1619-Cornelius Drebbel ( 1572 – 1633 ) presents, in London, a compound microscope with two convex lenses.

Traditional multifocal lenses have two or three distinct horizontal viewing areas, each requiring a conscious effort of refocusing.

The television camera on Surveyor 3 consisted of a vidicon tube, two 25 and 100 millimeter focal length lenses, shutters, filters, and an iris mounted along an axis inclined about 16 degrees to the central axis of the spacecraft.

Very few lenses, such as the Konica M-Hexanon Dual or Leica Tri-Elmar, let the user select among two or three focal lengths ; the viewfinder must be designed to work with all focal lengths of any lens used.

Very large binocular naval rangefinders ( up to 15 meters separation of the two objective lenses, weight 10 tons, for ranging World War II naval gun targets 25 km away ) have been used, although late-20th century technology made this application redundant.

The camera used two lenses to simultaneously expose a wide-angle and a high-resolution image on the same film.

The LCD shutter glasses rapidly alternate between the left and right lenses being opaque, used in tandem with two different alternating images flashed from the TV synchronized with the switching of the 3-D Glasses to create a natural stereoscopic 3D effect.

There are two basic configurations of the conventional optical microscope: the simple ( single lens ) and the compound ( many lenses ).

The eyepiece, or ocular, is a cylinder containing two or more lenses ; its function is to bring the image into focus for the eye.

In many designs, the virtual image comes to a focus between the two lenses of the eyepiece, the first lens bringing the real image to a focus and the second lens enabling the eye to focus on the virtual image.

The focus rings of the two lenses are coupled with gears around their circumference in this simple design.

Up until the beginning of the 20th century two separate lenses were cut in half and combined together in the rim of the frame.

The mounting of two half lenses into a single frame led to a number of early complications and rendered such spectacles quite fragile.

In rubber bridge, two partnerships participate in the game at one table and the objective is to score the most points in the play of several hands.

Elements of the two armies initially collided at Gettysburg on July 1, 1863, as Lee urgently concentrated his forces there, his objective being to engage the Union army and destroy it.

A supplementary thought experiment with the same objective of determining the occurrence of absolute rotation also was proposed by Newton: the example of observing two identical spheres in rotation about their center of gravity and tied together by a string.

In the 20th century, the ideas of Laplace were further developed in two different directions, giving rise to objective and subjective currents in Bayesian practice.

An object thus has two types of properties, intrinsic ( physical ) and objective ( observer specific )

The alternative crossbreeding programs initiated in 1940 by Dr. Antonio Teixeira Viana had the objective of obtaining first, crossbreeds 5 / 8 Charolais and 3 / 8 Zebu and second, 3 / 8 Charolais x 5 / 8 Zebu, to evaluate which of the two was the most successful.

By contrast, nouns have no distinct nominative and objective forms, the two being merged into a single plain case.

Contrary to what Frege states, in Husserl's Philosophy of Arithmetic we already find two different kinds of representations: subjective and objective.

When the objective of the analysis is to determine what stock to buy and at what price, there are two basic methodologies

The Internet Encyclopedia of Philosophy gives particular attention to two types of criticisms: the one questioning universality of human rights and the one denying them objective ground.

The spatial difference between the two beams is minimal ( less than the maximum resolution of the objective ).

Differential interference contrast requires a polarized light source to function ; two polarizing filters have to be fitted in the light path, one below the condenser ( the polarizer ), and the other above the objective ( the analyzer ).

Throughout 24 presentations and two debates with major Swiss media, this convention covered all subjects related to Mars exploration, from astronautics to architecture, not forgetting geology, the study of which remains its key objective.

" One way of interpreting such a statement would be: It is impossible to distinguish ' existence ' from ' non-existence ' as there are no objective qualities, and thus a reality, that one state could possess in order to discern between the two.

The genitive case is then usually called the possessive form and often is not considered as a noun case per se ; English is then said to have two cases, the subjective and the objective.

Each player's objective is generally to have as many disks one's own color at the end as possible and for one's opponent to have as few — or, technically in consideration of the occasional game in which not all disks are placed, that the difference between the two should be as large as possible if the winner and as small as possible if the loser.

Wolfenstein MultiPlayer ( MP ) is an objective game mode, in which players are split into two teams-Axis and Allies.

The Stockholm Bloodbath precipitated a lengthy hostility towards Danes in Sweden, and thenceforth the two nations were at almost continuous hostility with each other ( each with the objective of conquest or revenge upon the other ).

The subconscious mind view was advocated by psychical researcher Thomson Jay Hudson who wrote that the mind is a duality and actually consists of two minds: the objective mind ( conscious ) and the subjective mind ( subconscious ).

The objective of the Committee of 14 which consisted two leaders from each of the 7 provinces was the establishment of a democratically elected council of two leaders from each province to rule the country by consensus with the President as Head of State.

The objective of the sport is to score points by passing the ball through the other team's goals, a set of two upright posts separated by a crossbar above the ground.

In " Dialectal Materialism " of 1940, he saw idealism and materialism as two possible correlations between subjective thought and objective reality.

These two measures calculate the livability of countries and cities around the world, respectively, through a combination of subjective life-satisfaction surveys and objective determinants of quality of life such as divorce rates, safety, and infrastructure.

The ultimate goal of most levels is not to merely reach the end but to complete the type ( s ) of objective ( s ) specified: extermination of all or specific creatures, exploration of a level or locating an area in the level, retrieving one or more item, hitting a certain " repair " switch, or preventing half of the civilians from being killed ( a mission only present in two levels in the first game ).