Examples of convex lens in the following topics:

 A convex lens has been shaped so that all light rays that enter it parallel to its axis cross one another at a single point on the opposite side of the lens (the focal point).
 Such a lens is called a converging (or convex) lens for the converging effect it has on light rays.
 The word lens derives from the Latin word for lentil beanâ€”the shape of which is similar to that of the convex lens (as shown in ).
 The convex lens is shaped so that all light rays that enter it parallel to its axis cross one another at a single point on the opposite side of the lens.
 Such a lens is called a converging (or convex) lens for the corresponding effect it has on light rays.
 convex lens (noun) A lens having at least one convex surface, such that light passing through it, may be brought to a focus.
 concave lens (noun) A lens having at least one concave surface, such that light rays passing through it bend away from its optical axis.

 A magnifying glass is a convex lens that lets the observer see a larger image of the object being observed.
 The highest magnifying power is obtained by putting the lens very close to the eye and moving both the eye and the lens together to obtain the best focus.
 Since a magnifying glass uses its convex shape to focus light in a certain position, it can be used to converge the sun's radiation at the focus, causing hot spots.
 A magnifying glass is a convex lens that lets the observer see a larger image of the object under observation.
 A magnifying glass is a convex lens that lets the observer see a larger image of the object under observation.
 diopter (noun) a unit of measure of the power of a lens or mirror, equal to the reciprocal of its focal length in meters.
Myopia is diagnosed and measured in diopters
 lens (noun) an object, usually made of glass, that focuses or defocuses the light that passes through it

 The way that the image is formed is much like the way a convex lens forms an image.
 Layers of tissues with varying indices of refraction in the lens are shown here.
 The lens of the eye is similar to one in glasses or cameras.
 The lens provides the remaining power.
 The image passes through several layers of the eye, but happens in a way very similar to that of a convex lens.
 aperture (noun) The diameter of the aperture that restricts the width of the light path through the whole system.
For a telescope, this is the diameter of the objective lens (e.g., a telescope may have a 100 cm aperture).

 This aberration happens when the lens fails to focus all the colors on the same convergence point .
 shows chromatic aberration for a single convex lens.
 shows a twolens system using a diverging lens to partially correct for this, but it is nearly impossible to do so completely.
 Spherical aberrations are a form of aberration where rays converging from the outer edges of a lens converge to a focus closer to the lens, and rays closer to the axis focus further.
 The apparent effect is that of an image which has been mapped around a sphere, like in a fisheye lens.
 aberration (noun) The convergence to different foci, by a lens or mirror, of rays of light emanating from one and the same point, or the deviation of such rays from a single focus; a defect in a focusing mechanism that prevents the intended focal point.

 The focal point of the image will change depending on how the lens is shaped.
 The lens provides the remaining power.
 The image passes through several layers of the eye, but this happens in a way very similar to that of a convex lens.
 The eye's lens is flexible, and changes shape.
 The eye's ciliary muscles control the shape of the lens.

 A compound microscope is made of two convex lenses; the first, the ocular lens, is close to the eye, and the second is the objective lens.
 It is made of two convex lenses: the first, the ocular lens, is close to the eye; the second is the objective lens.
 The advantages of these microscopes, due to the multiple lenses, are the reduced chromatic aberrations and exchangeable objective lenses to adjust magnification.
shows a diagram of a compound microscope made from two convex lenses.
 The first lens is called the objective lens and is closest to the object being observed.
 The distance between the objective lens and the ocular lens is slightly shorter than the focal length of the ocular lens, f_{e}.

 The signs are reversed for the back surface of the lens: if R_{2} is positive the surface is concave, and if R_{2} is negative the surface is convex.
 A lens is biconvex (or double convex, or just convex) if both surfaces are convex.
 The signs of the lens' radii of curvature indicate whether the corresponding surfaces are convex or concave.
 The sign convention used to represent this varies, but for our treatment if R_{1} is positive the first surface is convex, and if R_{1} is negative the surface is concave.
 The signs are reversed for the back surface of the lens: if R_{2} is positive the surface is concave, and if R_{2} is negative the surface is convex.
 thick lens (noun) Lenses whose thicknesses are not negligible (i.e., one cannot make the simple assumption that a light ray is refracted only once in the lens).

 An ideal thin lens has two refracting surfaces but the lens is thin enough to assume that light rays bend only once.
 Another way of saying this is that the lens thickness is much much smaller than the focal length of the lens.
 A thin symmetrical lens has two focal points, one on either side and both at the same distance from the lens.
 The treatment of a lens as a thin lens is known as the "thin lens approximation
 Shows how to draw the ray diagrams for locating the image produced by a concave lens and a convex mirror.
 thin lens (noun) A thin lens is defined to be one whose thickness allows rays to refract but does not allow properties such as dispersion and aberrations.

 How does a lens form an image of an object?
 Recall the five basic rules of ray tracing:
A ray entering a converging lens parallel to its axis passes through the focal point F of the lens on the other side.
 The third ray passes through the nearer focal point on its way into the lens and leaves the lens parallel to its axis (rule 4).
 The three rays cross at the same point on the other side of the lens.
 Shows how to use the thin lens equation to calculate the image distance, image height and image orientation for convex lenses when the object distance is greater the the focal length (f).
 thin lens equation (noun) Relates object distance do, image distance di, and focal length f: $\frac{1}{d_o}+\frac{1}{d_i}=\frac{1}{f}$
 image distance (noun) The distance of the image from the center of the lens.

 In contrast to a simple lens, which consists of only one optical element, a compound lens is an array of simple lenses (elements) with a common axis.
 Note the sign convention: a telescope with two convex lenses (f_{1} 0, f_{2} 0) produces a negative magnification, indicating an inverted image.
 A convex plus a concave lens (f_{1} 0 f_{2}) produces a positive magnification and the image is upright.
 An achromatic lens or achromat is a lens that is designed to limit the effects of chromatic and spherical aberration.
 In the most common type (shown in ), the positive power of the crown lens element is not quite equaled by the negative power of the flint lens element.
 aberration (noun) The convergence to different foci, by a lens or mirror, of rays of light emanating from one and the same point, or the deviation of such rays from a single focus; a defect in a focusing mechanism that prevents the intended focal point.
 achromatic doublet (noun) A type of lens made up of two simple lenses paired together designed so that the chromatic aberration of each lens partially offsets the other; in this way light in a range of wavelengths may be brought to the same focus.