Abstract: A field effect transistor comprising: a non-doped diamond layer which has a hydrogen-terminated surface; first and second p+diamond layers which are formed on the non-doped diamond layer and sandwich a hydrogen-terminated region; a source electrode which is formed on the first p+diamond layer and is made of metal; a drain electrode which is formed on the second p+diamond layer and is made of metal; an insulating layer which is formed on the hydrogen-terminated region of the non-doped diamond layer; and a gate electrode which is formed on the insulating layer, a mutual conductance being equal to or higher than 0.5 mS/mm at room temperatures, after an X-ray is applied for an amount of 5 Mgy.

Abstract: An accessory mount can be inserted through the camera body mount without any of the first through third tabs being hindered by any of three camera body-side tabs at the camera body mount, as long as the accessory mount is inserted into the camera body mount at a correct interlock phase. The first, second, and third tabs extend over varying lengths along the circumferential direction. The first tab extends over a greatest length and the third tab extends over a smallest length, along the circumferential direction. The accessory mount includes a restricting member, a fitting portion, and a lock pin hole. The restricting member is disposed at a position assumed on a side substantially opposite from the lock pin hole across the fitting portion.

Abstract: An accessory mount can be inserted through the camera body mount without any of the first through third tabs being hindered by any of three camera body-side tabs at the camera body mount, as long as the accessory mount is inserted into the camera body mount at a correct interlock phase. The first, second, and third tabs extend over varying lengths along the circumferential direction. The first tab extends over a greatest length and the third tab extends over a smallest length, along the circumferential direction. The accessory mount includes a restricting member, a fitting portion, and a lock pin hole. The restricting member is disposed at a position assumed on a side substantially opposite from the lock pin hole across the fitting portion.

Abstract: An accessory mount can be inserted through the camera body mount without any of the first through third tabs being hindered by any of three camera body-side tabs at the camera body mount, as long as the accessory mount is inserted into the camera body mount at a correct interlock phase. The first, second, and third tabs extend over varying lengths along the circumferential direction. The first tab extends over a greatest length and the third tab extends over a smallest length, along the circumferential direction. The accessory mount includes a restricting member, a fitting portion, and a lock pin hole. The restricting member is disposed at a position assumed on a side substantially opposite from the lock pin hole across the fitting portion.

Abstract: An accessory mount can be inserted through the camera body mount without any of the first through third tabs being hindered by any of three camera body-side tabs at the camera body mount, as long as the accessory mount is inserted into the camera body mount at a correct interlock phase. The first, second, and third tabs extend over varying lengths along the circumferential direction. The first tab extends over a greatest length and the third tab extends over a smallest length, along the circumferential direction. The accessory mount includes a restricting member, a fitting portion, and a lock pin hole. The restricting member is disposed at a position assumed on a side substantially opposite from the lock pin hole across the fitting portion.

Abstract: An accessory mount can be inserted through the camera body mount without any of the first through third tabs being hindered by any of three camera body-side tabs at the camera body mount, as long as the accessory mount is inserted into the camera body mount at a correct interlock phase. The first, second, and third tabs extend over varying lengths along the circumferential direction. The first tab extends over a greatest length and the third tab extends over a smallest length, along the circumferential direction. The accessory mount includes a restricting member, a fitting portion, and a lock pin hole. The restricting member is disposed at a position assumed on a side substantially opposite from the lock pin hole across the fitting portion.

Abstract: An accessory mount can be inserted through the camera body mount without any of the first through third tabs being hindered by any of three camera body-side tabs at the camera body mount, as long as the accessory mount is inserted into the camera body mount at a correct interlock phase. The first, second, and third tabs extend over varying lengths along the circumferential direction. The first tab extends over a greatest length and the third tab extends over a smallest length, along the circumferential direction. The accessory mount includes a restricting member, a fitting portion, and a lock pin hole. The restricting member is disposed at a position assumed on a side substantially opposite from the lock pin hole across the fitting portion.

Abstract: An accessory mount can be inserted through the camera body mount without any of the first through third tabs being hindered by any of three camera body-side tabs at the camera body mount, as long as the accessory mount is inserted into the camera body mount at a correct interlock phase. The first, second, and third tabs extend over varying lengths along the circumferential direction. The first tab extends over a greatest length and the third tab extends over a smallest length, along the circumferential direction. The accessory mount includes a restricting member, a fitting portion, and a lock pin hole. The restricting member is disposed at a position assumed on a side substantially opposite from the lock pin hole across the fitting portion.

Abstract: A camera accessory can be detachably engaged with a camera body that includes a camera body mount, and is equipped with an accessory mount assuming a bayonet structure with a first tab, a second tab and a third tab set over intervals in a circumferential direction running along a circumference of a circle and projecting from the circumference along a radial direction. The accessory mount can be inserted through the camera body mount without any of the first through third tabs being hindered by any of three camera body-side tabs at the camera body mount, as long as the accessory mount is inserted into the camera body mount at a correct interlock phase. The accessory mount includes a restricting member disposed near the third tab.

Abstract: An accessory mount can be inserted through the camera body mount without any of the first through third tabs being hindered by any of three camera body-side tabs at the camera body mount, as long as the accessory mount is inserted into the camera body mount at a correct interlock phase. The first, second, and third tabs extend over varying lengths along the circumferential direction. The first tab extends over a greatest length and the third tab extends over a smallest length, along the circumferential direction. The accessory mount includes a restricting member, a fitting portion, and a lock pin hole. The restricting member is disposed at a position assumed on a side substantially opposite from the lock pin hole across the fitting portion.

Abstract: A camera accessory can be detachably engaged with a camera body that includes a camera body mount, and is equipped with an accessory mount assuming a bayonet structure with a first tab, a second tab and a third tab set over intervals in a circumferential direction running along a circumference of a circle and projecting from the circumference along a radial direction. The accessory mount can be inserted through the camera body mount without any of the first through third tabs being hindered by any of three camera body-side tabs at the camera body mount, as long as the accessory mount is inserted into the camera body mount at a correct interlock phase. The accessory mount includes a restricting member disposed near the third tab.

Abstract: An accessory mount can be inserted through the camera body mount without any of the first through third tabs being hindered by any of three camera body-side tabs at the camera body mount, as long as the accessory mount is inserted into the camera body mount at a correct interlock phase. The first, second, and third tabs extend over varying lengths along the circumferential direction. The first tab extends over a greatest length and the third tab extends over a smallest length, along the circumferential direction. The accessory mount includes a restricting member, a fitting portion, and a lock pin hole. The restricting member is disposed at a position assumed on a side substantially opposite from the lock pin hole across the fitting portion.

Abstract: An accessory mount can be inserted through the camera body mount without any of the first through third tabs being hindered by any of three camera body-side tabs at the camera body mount, as long as the accessory mount is inserted into the camera body mount at a correct interlock phase. The first tab, the second tab and the third tab extend over varying lengths along the circumferential direction. The first tab extends over a greatest length along the circumferential direction among the first through third tabs. The third tab extends over a smallest length along the circumferential direction among the first through third tabs. The accessory mount includes a restricting member disposed near the third tab, a fitting portion used to align an optical axis of the accessory mount with an optical axis of the camera body, and a lock pin hole through which a lock pin, retractably disposed at the camera body, is inserted so as to lock the camera accessory in a fully mounted state.

Abstract: A camera accessory can be detachably engaged with a camera body that includes a camera body mount, and is equipped with an accessory mount assuming a bayonet structure with a first tab, a second tab and a third tab set over intervals in a circumferential direction running along a circumference of a circle and projecting from the circumference along a radial direction. The accessory mount can be inserted through the camera body mount without any of the first through third tabs being hindered by any of three camera body-side tabs at the camera body mount, as long as the accessory mount is inserted into the camera body mount at a correct interlock phase. The accessory mount includes a restricting member disposed near the third tab.

Abstract: A camera accessory can be detachably engaged with a camera body that includes a camera body mount, and is equipped with an accessory mount assuming a bayonet structure with a first tab, a second tab and a third tab set over intervals in a circumferential direction running along a circumference of a circle and projecting from the circumference along a radial direction. The accessory mount can be inserted through the camera body mount without any of the first through third tabs being hindered by any of three camera body-side tabs at the camera body mount, as long as the accessory mount is inserted into the camera body mount at a correct interlock phase. The accessory mount includes a restricting member disposed near the third tab.

Abstract: A camera system having a predetermined image circle, comprises: an interchangeable lens having a lens mount portion; and a camera body having an image sensor that is disposed within that image circle, and a body mount portion, wherein, when a radius of circular portion at a maximum internal diameter part of an opening portion of the lens mount portion is termed rM, a flange back that is a distance from the lens mount portion to a light reception surface of an image sensor in a state that the interchangeable lens and the camera body are mutually engaged is termed da, and the diameter of the image circle is termed D, the following equations are satisfied: 14.0 mm?2rM?40.0 mm??Conditional Expression #1 16.0 mm?da?20.0 mm??Conditional Expression #2 14.0 mm?D?20.0 mm??Conditional Expression #3.

Abstract: An accessory side mount of the camera accessory includes at least a first limiting portion and a second limiting portion that is different from the first limiting portion. When the first through third claws are rotated in a first rotational direction along the circumferential direction in order to install the accessory side mount that has been inserted in the proper installation and detachment rotational phase into the body side mount, the first limiting portion limits a range of rotation in the first rotational direction by abutting an end surface of one of the camera body side claws. When the first through third claws are rotated in a second rotational direction along the circumferential direction that is opposite to the first rotational direction in order to detach the accessory side mount from the body side mount, the second limiting portion limits a range of rotation in the second rotational direction by abutting an end surface of one of the camera body side claws.

Abstract: An accessory side mount of the camera accessory includes at least a first limiting portion and a second limiting portion that is different from the first limiting portion. When the first through third claws are rotated in a first rotational direction along the circumferential direction in order to install the accessory side mount that has been inserted in the proper installation and detachment rotational phase into the body side mount, the first limiting portion limits a range of rotation in the first rotational direction by abutting an end surface of one of the camera body side claws. When the first through third claws are rotated in a second rotational direction along the circumferential direction that is opposite to the first rotational direction in order to detach the accessory side mount from the body side mount, the second limiting portion limits a range of rotation in the second rotational direction by abutting an end surface of one of the camera body side claws.

Abstract: A camera system having a predetermined image circle, comprises: an interchangeable lens having a lens mount portion; and a camera body having an image sensor that is disposed within that image circle, and a body mount portion, wherein, when a radius of circular portion at a maximum internal diameter part of an opening portion of the lens mount portion is termed rM, a flange back that is a distance from the lens mount portion to a light reception surface of an image sensor in a state that the interchangeable lens and the camera body are mutually engaged is termed da, and the diameter of the image circle is termed D, the following equations are satisfied: 14.0 mm?2rM?40.0 mm ??Conditional Expression #1 16.0 mm?da?20.0 mm ??Conditional Expression #2 14.0 mm?D?20.0 mm ??Conditional Expression #3.

Abstract: Providing an imaging apparatus wherein dust does not easily adhere to the imaging portion. The apparatus comprising an imaging portion provided with an image pickup device, a first housing holding the imaging portion, a protective cover disposed a photographic object side, a second housing holding the cover and provided with a mount structure, to attachably and removably mount interchangeable lenses at the photographic object side, and wherein an airtight space is formed by at least one of the first and the second housings, the imaging portion, and the cover.