Photographing apparatus having optical low-pass filter

Claim 2

A photographing apparatus comprising: taking lens means for determining an optical axis; and an optical member including a plurality of prism portions arrayed in succession at a predetermined pitch, wherein said optical member is arranged so that the optical axis is substantially located at a concave portion formed by one prism portion of said optical member and another prism portion adjacent said one prism portion, and wherein a cross section of each of said plurality of prism portions is of a trapezoidal shape, and wherein each of said trapezoidal-shaped prism portions has a slope plane and a top plane portion, and assuming that a width of said slope plane is B and a deviation amount between an apex of the concave portion and the optical axis is D, the following condition is satisfied: |D|/B<0.33, and wherein assuming that the width of said top plane portion is A, the pitch is P, a first order diffraction angle of said optical member is θ f , and a refraction angle of said slope plane is θ r , the following further conditions are satisfied: 0.15<A/P<0.35, and 0.5<θ.sub.r /θ.sub.f <1.4.

Claim 3

The photographing apparatus according to claim 1, further comprising a stop with a changeable aperture, the center of the aperture being coincident with the optical axis.

Claim 4

A photographing apparatus comprising: a taking lens, which determines an optical axis; and an optical low-pass filter comprising a pair of low-pass filter portions each including prism portions each having slope planes and a plane portion, which have a boundary portion between said prism portions that are adjacent, said prism portions being arrayed at a predetermined pitch P, wherein said low-pass filter portions are positioned adjacent to each other at an adjoining portion of said optical low-pass filter, and wherein said prism portions of one of said pair of low-pass filter portions are shifted with respect to said prism portions of the other of said pair of low-pass filter portions, along the adjoining portion, by a deviation amount of P/2, and wherein said optical low-pass filter is arranged so that the optical axis intersects the boundary portion of one of said prism portions.

Claim 5

A photographing apparatus comprising: a taking lens, which determines an optical axis; and an optical low-pass filter comprising a pair of low-pass filter portions each including prism portions each having slope planes and a plane portion, which have a boundary portion between said prism portions that are adjacent, said prism portions being arrayed at a predetermined pitch P, wherein said low-pass filter portions are positioned adjacent to each other at an adjoining portion of said optical low-pass filter, and wherein said prism portions of one of said pair of low-pass filter portions are shifted with respect to said prism portions of the other of said pair of low-pass filter portions, along the adjoining portion, by a deviation amount of P/2, and wherein said optical low-pass filter is arranged so that the optical axis intersects the boundary portion of one of said prism portions.

Claim 6

The photographing apparatus according to claim 3, wherein assuming that a refraction angle of a light flux at said slope plane is θ r , and a first order diffraction angle of said optical filter is θ f , the following condition is satisfied: 0.5<θ.sub.r /θ.sub.f <1.4.

Claim 7

The photographing apparatus according to claim 3, wherein assuming that a width of said plane portion is D, the following condition is satisfied: 0.15<D/P<0.35.

Claim 8

A photographing apparatus comprising: a taking lens, which determines an optical axis; and an optical low-pass filter comprising a pair of low-pass filter portions each including prism portions each having slope planes and a plane portion, which have a boundary portion between said prism portions that are adjacent, said prism portions being arrayed at a predetermined pitch P, wherein said low-pass filter portions are positioned adjacent to each other at an adjoining portion of said optical low-pass filter, and wherein said prism portions of one of said pair of low-pass filter portions are shifted with respect to said prism portions of the other of said pair of low-pass filter portions, along the adjoining portion, by a deviation amount, which is less than or equal to the pitch P of said prism portions, and wherein said optical low-pass filter is arranged so that the optical axis intersects the boundary portion of one of said prism portions, and wherein assuming that a refraction angle of a light flux at said slope planes is θ r , and a first order diffraction angle of said optical filter is θ f , the following condition is satisfied: 0.5<θ.sub.r /θ.sub.f <1.4.

Claim 9

A photographing apparatus comprising: a taking lens, which determines an optical axis; and an optical low-pass filter comprising a pair of low-pass filter portions each including prism portions each having slope planes and a plane portion, which have a boundary portion between said prism portions that are adjacent, said prism portions being arrayed at a predetermined pitch P, wherein said low-pass filter portions are positioned adjacent to each other at an adjoining portion of said optical low-pass filter, and wherein said prism portions of one of said pair of low-pass filter portions are shifted with respect to said prism portions of the other of said pair of low-pass filter portions, along the adjoining portion, by a deviation amount, which is less than or equal to the pitch P of said prism portions, and wherein said optical low-pass filter is arranged so that the optical axis intersects the boundary portion of one of said prism portions, and wherein assuming that a refraction angle of a light flux at said slope planes is θ r , and a first order diffraction angle of said optical filter is θ f , the following condition is satisfied: 0.5<θ.sub.r /θ.sub.f <1.4.

Claim 10

The photographing apparatus according to claim 6, wherein the deviation amount is P/2.

Claim 11

The photographing apparatus according to claim 6, wherein assuming that a width of said plane portion is D, the following condition is satisfied: 0.15<D/P<0.35.

Claim 14

An apparatus according to claim 9, wherein the first-order diffraction angle θ f is substantially equal to the refraction angle θ r .

Claim 17

An apparatus according to claim 11, wherein the first-order diffraction angle θ f is substantially equal to the refraction angle θ r .