An Image forming method using a multi-plane varifocal lens, characterized in that the method is performed in a device comprising an imaging optical system (2, 3) and an active gradient refractive index plate made of a thermo-optical material with a homogeneous refractive index distribution, wherein a diverging or converging type of varifocal thermal active gradient refractive index lens is created by directing a heating laser beam propagating in a direction parallel to the optical axis of the optical system onto the active gradient refractive index plate, thereby creating the multi-plane varifocal lens, wherein the active gradient refractive index lens has a diameter smaller than the diameter of the aperture of the imaging optical system in order to create a multi-planar image the method further comprising to place at least one converging lens of the imaging optical system in such a way that light rays from a part of a first observed object pass through the region of the active gradient refractive index lens as well as through the region with a homogeneous refractive index distribution of the active gradient refractive index plate, wherein all of the rays that pass through the active gradient refractive index plate also pass through the at least one converging lens, and as a result of which, the rays from the first observed object that pass through the active gradient refractive index lens form a sharp image (4") of the part of the first observed object at a different imaging distance measured from the second plane of the main active gradient refractive index lens than the rays from the first observed object which do pass through the part of the active gradient refractive index plate having a homogeneous refractive index distribution, the active gradient refractive index lens forming a sharp image of a part of the first observed object at the same image distance measured from the second plane of the main active gradient refractive index lens, in which an image of a second observed object appears, wherein the second observed object is located in a different plane than the first observed object, wherein all the light rays that pass through the optical system which are used for imaging pass through the active gradient refractive index lens creating a sharp image of the second observed object in one image plane identical to the plane in which a sharp image of the part of the first observed object was created, in this manner thereby creating a multi-plane, uniform, sharp image of the part of the first observed object and the second observed object, wherein after creating a further active gradient refractive index lens (6") in the active gradient refractive index plate with a parallel axis of symmetry not overlapping with the optical axis of the system, all light rays passing through a part of a third observed object that pass through the imaging optical system and pass through the further active gradient refractive index lens (6") form a sharp image of the part of the third observed object in the same plane in which the images and of the first and second observed object were created, thus creating a multi-plane, uniform, sharp image from the combination of the image of the part of the first observed object, image of the second observed object and image of the part of the third observed object, the three observed objects lying in different planes.