If the angle u1 is very small, O ' 1 is the Gaussian image ; and O ' 1 O ' 2 is termed the longitudinal aberration, and O ' 1R the lateral aberration of the pencils with aperture u2.

If the system be entirely behind the aperture stop, then this is itself the entrance pupil ( front stop ); if entirely in front, it is the exit pupil ( back stop ).

If the above errors be eliminated, the two astigmatic surfaces united, and a sharp image obtained with a wide aperture — there remains the necessity to correct the curvature of the image surface, especially when the image is to be received upon a plane surface, e. g. in photography.

If an aperture is wide, then uncollimated rays are admitted, resulting in a sharp focus only for rays with a certain focal length.

If two cameras of different format sizes and focal lengths have the same angle of view, and the same aperture area, they gather the same amount of light from the scene.

If the motion goes far enough, this motion causes the lever arms to pull down on a thrust bearing, which moves a beam linkage, which reduces the aperture of a throttle valve.

If the subject image size remains the same, then at any given aperture all lenses, wide angle and long lenses, will give the same depth of field.

If the source has a maximum overall dimension or aperture width ( D ) that is large compared to the wavelength λ, the far-field region is commonly taken to exist at distances from the source, greater than Fresnel parameter S = D < sup > 2 </ sup >/( 4λ ), S > 1.

If the conditions for far field are not met ( for example if the aperture is large ), the far-field Airy diffraction pattern can also be obtained on a screen much closer to the aperture by using a lens right after the aperture ( or the lens itself can form the aperture ).

If a lens after the aperture is used, the Airy pattern forms at the focal plane of the lens, where R = f ( f is the focal length of the lens ).

If a designer knew precisely about the display's electron beams and aperture grille, subpixel rendering might have some advantage.

If the Director does not want another take, the AD will call " Check the gate " ( a signal for the Focus Puller or Camera Assistant to confirm that the camera has not malfunctioned during a take, and that there is no hair or fluff in the aperture (" gate ") where the film is exposed ).

If two observations of the same terrain from very similar positions are available, aperture synthesis can be performed to provide the resolution performance which would be given by a RADAR system with dimensions equal to the separation of the two measurements.

If the lens designer optimised for sharpness only, the lens would have a small minimum aperture and would be sharpest at full aperture, but would produce too dim an image for some poorly lit scenes.

If you for example, wish to use a modern lens without aperture ring, on an old camera, adapter or converter without the needed electronic connections.

If the blurred light is circular, then it can be inferred that the aperture is either round or the image was shot " wide-open " ( with the blades recessed into the sides of the lens, allowing the interior edge of the lens barrel to effectively become the iris ).

If we take the example of a V = 28 star observed through a normal V band filter ( µm bandpass, frequency Hz ), the number of photons we receive per square cm of telescope aperture per second from the source is:

If a simple open-ended waveguide is used as an antenna, without the horn, the sudden end of the conductive walls causes an abrupt impedance change at the aperture, from the wave impedance in the waveguide to the impedance of free space, ( about 377 ohms ).

If an antenna delivers an output power of P < sub > o </ sub > watts to the load connected to its output terminals when irradiated by a uniform field of power density PFD watts per square metre, the antenna's aperture A < sub > eff </ sub > in square metres is given by:

If the antenna were perfectly efficient, all the radio power falling within its physical aperture would be converted to electrical power delivered to the load attached to its output terminals, so these two areas would be equal A < sub > eff </ sub > = A < sub > phys </ sub > and the aperture efficiency would be 1. 0.

If the circumstances are faced frankly it is not reasonable to expect this to be true.

If his dancers are sometimes made to look as if they might be creatures from Mars, this is consistent with his intention of placing them in the orbit of another world, a world in which they are freed of their pedestrian identities.

If a work is divided into several large segments, a last-minute drawing of random numbers may determine the order of the segments for any particular performance.

If they avoid the use of the pungent, outlawed four-letter word it is because it is taboo ; ;

If Wilhelm Reich is the Moses who has led them out of the Egypt of sexual slavery, Dylan Thomas is the poet who offers them the Dionysian dialectic of justification for their indulgence in liquor, marijuana, sex, and jazz.

If he is the child of nothingness, if he is the predestined victim of an age of atomic wars, then he will consult only his own organic needs and go beyond good and evil.

If it is an honest feeling, then why should she not yield to it??

If he thus achieves a lyrical, dreamlike, drugged intensity, he pays the price for his indulgence by producing work -- Allen Ginsberg's `` Howl '' is a striking example of this tendency -- that is disoriented, Dionysian but without depth and without Apollonian control.

If love reflects the nature of man, as Ortega Y Gasset believes, if the person in love betrays decisively what he is by his behavior in love, then the writers of the beat generation are creating a new literary genre.

If he is good, he may not be legal ; ;

If the man on the sidewalk is surprised at this question, it has served as an exclamation.

If the existent form is to be retained new factors that reinforce it must be introduced into the situation.

If we remove ourselves for a moment from our time and our infatuation with mental disease, isn't there something absurd about a hero in a novel who is defeated by his infantile neurosis??

If many of the characters in contemporary novels appear to be the bloodless relations of characters in a case history it is because the novelist is often forgetful today that those things that we call character manifest themselves in surface behavior, that the ego is still the executive agency of personality, and that all we know of personality must be discerned through the ego.

If he is a traditionalist, he is an eclectic traditionalist.

If our sincerity is granted, and it is granted, the discrepancy can only be explained by the fact that we have come to believe hearsay and legend about ourselves in preference to an understanding gained by earnest self-examination.

If to be innocent is to be helpless, then I had been -- as are we all -- helpless at the start.

:“ If an integer n is greater than 2, then has no solutions in non-zero integers a, b, and c. I have a truly marvelous proof of this proposition which this margin is too narrow to contain .”

If the species concerned were short-lived ( in geological terms, lasting a few hundred thousand years ), then it is certain that the sediments in question were deposited within that narrow time period.

If the American electorate is so narrow as not to elect a Unitarian, well and good.

If the deviations from ideality are not too strong, Raoult's law will still be valid in a narrow concentration range when approaching x = 1 for the majority phase ( the solvent ).

If the system under test were to radiate all its energy in a narrow bandwidth, it would register a large peak.

If the species concerned were short-lived ( in geological terms, lasting a few hundred thousand years ), then it is certain that the sediments in question were deposited within that narrow time period.

If they are not the same, i. e. some are narrow triangles, while others maybe wide trapizoids or shouldered triangles, then the mass or area of the output function must be known or calculated.

If short-term interest rates were expected to fall in a contango market, this would narrow the spread between a futures contract and an underlying asset in good supply.

If it is Cornish then ' Dun ' would = Fort ( Oliver Padel proposes ' Dun ' '- tagell ' ( narrow place ) in his book on place name elements and may be right ); there is a possible cognate form in the Channel Islands: Tente d ' Agel, but that still leaves the question subject to doubt.

If the boat is not horse-drawn, it may have a refurbished, slow-revving, vintage diesel engine, and there are even some steam-driven narrow boats such as the ex-Fellows Morton and Clayton steamer President.

If the reflectivity is high, resulting in a high Q factor ( i. e. high finesse ), monochromatic light produces a set of narrow bright rings against a dark background.

If a patient needs frequent venous access, the veins may scar and narrow, making any future access extremely difficult or impossible.

If the reflectivity is high, resulting in a high Q factor, monochromatic light produces a set of narrow bright rings against a dark background.

If the range of character in which Kean attained supreme excellence was narrow, no one except David Garrick was so successful in so many great roles.

If their organizations struggled, he believed it was usually because of outdated ideas, a narrow conception of problems, or internal misunderstandings.

If the chimney was particularly narrow the boys would be told to " buff it ", that is to do it naked, otherwise they just wore trousers, and a shirt made from thick rough cotton cloth.

If, however, the broad definition of narration includes all written fiction, and the narrow definition is limited merely to that which is directly communicated to the reader, what comprises the rest of written fiction?

If enough moisture and upward motion is present, precipitation falls from convective clouds such as cumulonimbus and can organize into narrow rainbands.

If the gamma zone shows an increase ( or spike ), the first step in interpreting the graph is to establish if the region is narrow or wide.

If it is elevated it could be elevated in a single narrow " spike-like " manner indicating monoclonal gammopathy or a broad " swell-like " manner ( wide ) indicating polyclonal gammopathy.

If the sea was rough they had to clamber around the rocks on a very narrow track on the crater ’ s edge.

If only Additive genetic variance ( V < sub > A </ sub >) is used in the numerator, the heritability is " narrow sense " ( h < sup > 2 </ sup >).

If the target function creates a narrow ridge that ascends in a non-axis-aligned direction ( or if the goal is to minimize, a narrow alley that descends in a non-axis-aligned direction ), then the hill climber can only ascend the ridge ( or descend the alley ) by zig-zagging.