A viewfinder with which an observing or image-recording device, such as a spotting scope or image-recording apparatus, is intended to be equipped, the observing device being configured to produce an image of an observed scene. The viewfinder allows a first image, representative of the observed scene, and a second image, different from the first image, to be displayed, the first image and the second image being juxtaposed with respect to each other. The observing device includes a first optical system and a second optical system configured to propagate the first image and the second image towards the eye of a user, along two distinct axes of propagation, respectively. The optical systems are such that passage from observing one image to observing the other image is achieved through simple natural rotation of the eye.