Exposure control device for interchangeable-lens camera

Claim 2

An exposure control device in which, in determining a correct amount of exposure for an interchange­able-lens camera using a photometric output ip obtained through a photographing lens, correction is effected such that said photometric output ip and the open-aperture F number A vmin of said photographing lens satisfy the proportional relation: ₂A vmin ∝ 1/ip characterized by means for obtaining an amount of correction mv₁ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between different camera bodies and a difference in focal length between different photographing lenses; and means for correcting said deviation from said propor­tional relation according to said amount of correction mv₁.

Claim 3

As exposure control device in which, in determining a correct amount of exposure for an interchange­able-lens camera using a photometric output ip obtained through a photographing lens, correction is effected such that said photometric output ip and the open-aperture F number A vmin of said photographing lens satisfy the proportional relation: ₂A vmin α 1/ip characterized by means for obtaining an amount of correction mv₂ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between said camera bodies and a difference in exit pupil position between said photographing lenses; and means for correcting said deviation from said propor­tional relation according to said amount of correction mv₂.

Claim 4

As exposure control device in which, in determining a correct amount of exposure for an interchange­able-lens camera using a photometric output ip obtained through a photographing lens, correction is effected such that said photometric output ip and the open-aperture F number A vmin of said photographing lens satisfy the proportional relation: ₂A vmin α 1/ip characterized by means for obtaining an amount of correction mv₂ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between said camera bodies and a difference in exit pupil position between said photographing lenses; and means for correcting said deviation from said propor­tional relation according to said amount of correction mv₂.

Claim 5

An exposure control device in which, in determining a correct amount of exposure for an interchange­able-lens camera using a photometric output ip obtained through a photographing lens, correction is effected such that said photometric output ip and the open-aperture F number A vmin of said photographing lens satisfy the proportional relation: ₂A vmin ∝ 1/ip characterized by means for obtaining an amount of correction mv₃ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between said camera bodies and a difference in vignetting factor between said photographing lenses; and means for correcting said deviation from said propor­tional relation according to said amount of correction mv₃.

Claim 6

An exposure control device in which, in determining a correct amount of exposure for an interchange­able-lens camera using a photometric output ip obtained through a photographing lens, correction is effected such that said photometric output ip and the open-aperture F number A vmin of said photographing lens satisfy the proportional relation: ₂A vmin ∝ 1/ip characterized by means for obtaining an amount of correction mv₃ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between said camera bodies and a difference in vignetting factor between said photographing lenses; and means for correcting said deviation from said propor­tional relation according to said amount of correction mv₃.

Claim 7

An exposure control device in which, in determining a correct amount of exposure for an interchange­ able-lens camera using a photometric output ip obtained through a photographing lens, correction is effected such that said photometric output ip and the open-aperture F number A vmin of said photographing lens satisfy the proportional relation: ₂A vmin ∝ 1/ip characterized by means for obtaining an amount of correction mv₄ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between said camera bodies and a difference in open-aperture F number between said photographing lenses; and means for correcting said deviation from said propor­tional relation according to said amount of correction mv₄.

Claim 8

An exposure control device in which, in determining a correct amount of exposure for an interchange­ able-lens camera using a photometric output ip obtained through a photographing lens, correction is effected such that said photometric output ip and the open-aperture F number A vmin of said photographing lens satisfy the proportional relation: ₂A vmin ∝ 1/ip characterized by means for obtaining an amount of correction mv₄ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between said camera bodies and a difference in open-aperture F number between said photographing lenses; and means for correcting said deviation from said propor­tional relation according to said amount of correction mv₄.

Claim 9

An exposure control device in which, in determining a correct amount of exposure for an interchange­able-lens camera using a photometric output ip obtained through a photographing lens, correction is effected such that said photometric output ip and the open-aperture F number A vmin of said photographing lens satisfy the proportional relation: ₂A vmin ∝ 1/ip characterized by means for obtaining an amount of correction mv₁ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between different camera bodies and a difference in focal length between different photographing lenses: means for obtaining an amount of correction mv₂ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between said camera bodies and a difference in exit pupil position between said photographing lenses, an amount of correction mv₃ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between said camera bodies and a difference in vignetting factor between said photographing lenses, and an amount of correc­tion mv₄ to correct a deviation from said proportional rela­tion attributed to a difference in optical characteristics between said camera bodies and a difference in open-aperture F number between said photographing lenses; and means for correcting said deviation from said propor­tional relation according to the sum of at least one, two or three of said amounts of correction mv₁, mv₂, mv₃ and mv₄.

Claim 10

An exposure control device in which, in determining a correct amount of exposure for an interchange­able-lens camera using a photometric output ip obtained through a photographing lens, correction is effected such that said photometric output ip and the open-aperture F number A vmin of said photographing lens satisfy the proportional relation: ₂A vmin ∝ 1/ip characterized by means for obtaining an amount of correction mv₁ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between different camera bodies and a difference in focal length between different photographing lenses: means for obtaining an amount of correction mv₂ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between said camera bodies and a difference in exit pupil position between said photographing lenses, an amount of correction mv₃ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between said camera bodies and a difference in vignetting factor between said photographing lenses, and an amount of correc­tion mv₄ to correct a deviation from said proportional rela­tion attributed to a difference in optical characteristics between said camera bodies and a difference in open-aperture F number between said photographing lenses; and means for correcting said deviation from said propor­tional relation according to the sum of at least one, two or three of said amounts of correction mv₁, mv₂, mv₃ and mv₄.

Claim 11

An exposure control device in which, in determining a correct amount of exposure for an interchange­able-lens camera using a photometric output ip obtained through a photographing lens, correction is effected such that said photometric output ip and the open-aperture F number A vmin of said photographing lens satisfy the proportional relation: ₂A vmin ∝ 1/ip characterized by means for obtaining an amount of correction mv₁ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between different camera bodies and a difference in focal length between different photographing lenses; means for obtaining an amount of correction mv₂ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between said camera bodies and a difference in exit pupil position between said photographing lenses, an amount of correction mv₃ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between said camera bodies and a difference in vignetting factor between said photographing lenses, and an amount of correc­tion mv₄ to correct a deviation from said proportional rela­tion attributed to a difference in optical characteristics between said camera bodies and a difference in open-aperture F number between said photographing lenses; and means for correcting said deviation from said propor­tional relation according to the sum of said amounts of correction mv₁, mv₂, mv₃ and mv₄.

Claim 12

An exposure control device in which, in determining a correct amount of exposure for an interchange­able-lens camera using a photometric output ip obtained through a photographing lens, correction is effected such that said photometric output ip and the open-aperture F number A vmin of said photographing lens satisfy the proportional relation: ₂A vmin ∝ 1/ip characterized by means for obtaining an amount of correction mv₁ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between different camera bodies and a difference in focal length between different photographing lenses; means for obtaining an amount of correction mv₂ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between said camera bodies and a difference in exit pupil position between said photographing lenses, an amount of correction mv₃ to correct a deviation from said proportional relation attributed to a difference in optical characteristics between said camera bodies and a difference in vignetting factor between said photographing lenses, and an amount of correc­tion mv₄ to correct a deviation from said proportional rela­tion attributed to a difference in optical characteristics between said camera bodies and a difference in open-aperture F number between said photographing lenses; and means for correcting said deviation from said propor­tional relation according to the sum of said amounts of correction mv₁, mv₂, mv₃ and mv₄.

Claim 13

The device as claimed in claim 1, wherein said obtaining means comprises: means for storing coefficients a₁, a₂, a₃, a₄, b₁ and b₂ in said camera body and means for storing data f, 1/EXP, VNT and A vminef in a lens ROM of said photographing lens, and means for calculating said amounts of correction mv₁, mv₂, mv₃ and mv₄ according to the following equations: mv₁ = a₁ x 1/f mv₂ = a₂ x 1/EXP + b₁ mv₃ = a₃ x VNT mv₄ = a₄ x A vminef + b₂ where f is the focal length, EXP is an exit pupil position, VNT is vignetting factor with an image having a predetermined height, and A vminef is open-aperture F number.

Claim 14

The device as claimed in claim 7, wherein said memory in said camera body is a ROM.

Claim 15

The device as claimed in claim 7, wherein said memory in said camera body is a ROM.

Claim 16

The device as claimed in claim 8, wherein said ROM is an E²PROM.

Claim 17

The device as claimed in claim 9, wherein said ROM is an E²PROM.

Claim 18

The device as claimed in claim 7, wherein said predetermined image height is 6 mm.

Claim 19

The device as claimed in claim 7, wherein said means for storing in said camera body for storing coefficients a₁ through a₄, and b₁ and b₂ with respect to each of photometry systems in case of said camera body having a plurality of photometry systems.

Claim 20

An interchangeable photographing lens system for use in a TTL photographic interchangeable lens camera in which, in determining a correct amount of exposure for said camera using a photometric output ip obtained through said lens system, correction is effected such that the photometric output ip and an open-aperture F number A vmin of said photographing lens system satisfy the proportional relation: ₂A vmin ∝ 1/ip comprising means for storing at least one of data f, 1/EXP, VNT and A vminef where f is a focal length of said lens system, EXP is an exit pupil position, VNT is vignetting factor with an image having a predetermined height, and A vminef is open-aperture F number.

Claim 21

An interchangeable photographing lens system for use in a TTL photographic interchangeable lens camera in which, in determining a correct amount of exposure for said camera using a photometric output ip obtained through said lens system, correction is effected such that the photometric output ip and an open-aperture F number A vmin of said photographing lens system satisfy the proportional relation: ₂A vmin ∝ 1/ip comprising means for storing at least one of data f, 1/EXP, VNT and A vminef where f is a focal length of said lens system, EXP is an exit pupil position, VNT is vignetting factor with an image having a predetermined height, and A vminef is open-aperture F number.

Claim 22

A camera for a TTL photometric photographic interchangeable lens camera in which, in determining a correct amount of exposure for said camera using a photometric output ip obtained through said lens system, correct is effected such that the photometric output ip and an open-aperture F number A vmin of said photographing lens system satisfy the proportional relation: ₂A vmin ∝ 1/ip comprising means for storing coefficients a₁, a₂, a₃, a₄, b₁ and b₂ to be used in calculation of amounts of correction mv₁, mv₂, mv₃ and mv₄ according to the following equations: mv₁ = a₁ x 1/f mv₂ = a₂ x 1/EXP + b₁ mv₃ = a₃ x VNT mv₄ = a₄ x A vminef + b₂ where f is the focal length, EXP is an exit pupil position, VNT is vignetting factor with an image having a predetermined height, and A vminef is open-aperture F number.

Claim 23

A camera for a TTL photometric photographic interchangeable lens camera in which, in determining a correct amount of exposure for said camera using a photometric output ip obtained through said lens system, correct is effected such that the photometric output ip and an open-aperture F number A vmin of said photographing lens system satisfy the proportional relation: ₂A vmin ∝ 1/ip comprising means for storing coefficients a₁, a₂, a₃, a₄, b₁ and b₂ to be used in calculation of amounts of correction mv₁, mv₂, mv₃ and mv₄ according to the following equations: mv₁ = a₁ x 1/f mv₂ = a₂ x 1/EXP + b₁ mv₃ = a₃ x VNT mv₄ = a₄ x A vminef + b₂ where f is the focal length, EXP is an exit pupil position, VNT is vignetting factor with an image having a predetermined height, and A vminef is open-aperture F number.