A lens apparatus having a zooming function and being attachable and detachable to a camera apparatus, the lens apparatus comprising: a memory storing information for light amount compensation for image data obtained by pickup with the camera apparatus of an image formed by the lens apparatus with respect to each of a plurality of focal lengths of the lens apparatus; and a communication device configured to transmit the information to the camera apparatus, wherein the information includes a coefficient of a polynomial having an n-th order with respect to an image height, n being a non-negative integer, wherein the memory stores the information with respect to each of the plurality of focal lengths such that the plurality of focal lengths includes a focal length f satisfying a conditional expression 0.9 < f / ft ⋅ Fnw / Fnt < 4 where Fnw represents an effective f-number in a full aperture state and at a wide angle end, Fnt represents an effective f-number in the full aperture state and at a telephoto end, and ft represents a focal length at the telephoto end; and wherein a conditional expression 0.01 < F n f + Δf − F nf − F nf − F n f − Δf / N f ± Δf < 0.2 is satisfied in a range of the focal length f in which a conditional expression 0.5 < F n f + Δf − F nf − F nf − F n f − Δf < 5.0 is satisfied where Δf is defined by an expression Δ f = 0.2 × ft − fw, where N (f±Δf) represents a number of focal lengths included in a focal length range not less than (f-Δf) and not greater than (f + Δf) of the plurality of focal lengths, F nf represents an effective f-number in the full aperture state and at the focal length f, F n(f-Δf) represents an effective f-number in the full aperture state and at a focal length f-Δf, F n(f+Δf) represents an effective f-number in the full aperture state and at a focal length f+Δf, and fw represents a focal length at the wide angle end. a memory storing information for light amount compensation for image data obtained by pickup with the camera apparatus of an image formed by the lens apparatus with respect to each of a plurality of focal lengths of the lens apparatus; and a communication device configured to transmit the information to the camera apparatus, wherein the information includes a coefficient of a polynomial having an n-th order with respect to an image height, n being a non-negative integer, wherein the memory stores the information with respect to each of the plurality of focal lengths such that the plurality of focal lengths includes a focal length f satisfying a conditional expression 0.9 < f / ft ⋅ Fnw / Fnt < 4 where Fnw represents an effective f-number in a full aperture state and at a wide angle end, Fnt represents an effective f-number in the full aperture state and at a telephoto end, and ft represents a focal length at the telephoto end; and wherein a conditional expression 0.01 < F n f + Δf − F nf − F nf − F n f − Δf / N f ± Δf < 0.2 is satisfied in a range of the focal length f in which a conditional expression 0.5 < F n f + Δf − F nf − F nf − F n f − Δf < 5.0 is satisfied where Δf is defined by an expression Δ f = 0.2 × ft − fw, where N (f±Δf) represents a number of focal lengths included in a focal length range not less than (f-Δf) and not greater than (f + Δf) of the plurality of focal lengths, F nf represents an effective f-number in the full aperture state and at the focal length f, F n(f-Δf) represents an effective f-number in the full aperture state and at a focal length f-Δf, F n(f+Δf) represents an effective f-number in the full aperture state and at a focal length f+Δf, and fw represents a focal length at the wide angle end.