A viewfinder, configured to be placed facing an eye of a user of an observing device, the observing device comprising an observation objective intended to form an image of an observed scene, the viewfinder comprising: - a means (7,8,11,17) for forming a first image, representative of the observed scene; - a first optical system, coupled to the means for forming the first image, and arranged to propagate the first image to a first exit pupil (PS 1), about a first optical axis, the light rays forming the first image reaching the first exit pupil by propagating about the first optical axis; wherein the viewfinder comprises: - a secondary display, emitting a second image, different from the first image; - a second optical system, lying between the display and a second exit pupil (PS 2), about a second optical axis, inclined with respect to the first optical axis, the second optical system being configured to propagate the second image to the second exit pupil (PS 2), the light rays forming the second image reaching the second exit pupil by propagating about the second optical axis; and wherein: - the first exit pupil and the second exit pupil are tangent to the same spherical surface, the diameter of which is comprised between 1.5 cm and 3 cm, so that the spherical-surface diameter corresponds to the ocular diameter; - the first optical axis and the second optical axis converge, to a point of convergence, corresponding to the centre of said spherical surface, so that the point of convergence is located in the eye of the user such that the user may view • the first image when the eye is oriented along the first optical axis; • the second image when the eye is oriented along the second optical axis. - a means (7,8,11,17) for forming a first image, representative of the observed scene; - a first optical system, coupled to the means for forming the first image, and arranged to propagate the first image to a first exit pupil (PS 1), about a first optical axis, the light rays forming the first image reaching the first exit pupil by propagating about the first optical axis; wherein the viewfinder comprises: - a secondary display, emitting a second image, different from the first image; - a second optical system, lying between the display and a second exit pupil (PS 2), about a second optical axis, inclined with respect to the first optical axis, the second optical system being configured to propagate the second image to the second exit pupil (PS 2), the light rays forming the second image reaching the second exit pupil by propagating about the second optical axis; - a secondary display, emitting a second image, different from the first image; - a second optical system, lying between the display and a second exit pupil (PS 2), about a second optical axis, inclined with respect to the first optical axis, the second optical system being configured to propagate the second image to the second exit pupil (PS 2), the light rays forming the second image reaching the second exit pupil by propagating about the second optical axis; and wherein: - the first exit pupil and the second exit pupil are tangent to the same spherical surface, the diameter of which is comprised between 1.5 cm and 3 cm, so that the spherical-surface diameter corresponds to the ocular diameter; - the first optical axis and the second optical axis converge, to a point of convergence, corresponding to the centre of said spherical surface, so that the point of convergence is located in the eye of the user such that the user may view • the first image when the eye is oriented along the first optical axis; • the second image when the eye is oriented along the second optical axis. - the first exit pupil and the second exit pupil are tangent to the same spherical surface, the diameter of which is comprised between 1.5 cm and 3 cm, so that the spherical-surface diameter corresponds to the ocular diameter; - the first optical axis and the second optical axis converge, to a point of convergence, corresponding to the centre of said spherical surface, so that the point of convergence is located in the eye of the user such that the user may view • the first image when the eye is oriented along the first optical axis; • the second image when the eye is oriented along the second optical axis. • the first image when the eye is oriented along the first optical axis; • the second image when the eye is oriented along the second optical axis.