Abstract: A control apparatus for a camera system that includes a lens apparatus including a first optical system and a second optical system and configured to move them relative to each other, and an image pickup apparatus including an image sensor and detachably attachable to the lens apparatus includes a processor configured to acquire a first evaluation value of the first optical system at a first focus detection position corresponding to the first optical system, determine a second focus detection position corresponding to the second optical system based on an first object image formed by the first optical system and a second object image formed by the second optical system, acquire a second evaluation value of the second optical system at the second focus detection position, and move the first optical system and the second optical system based on the first evaluation value and the second evaluation value.

Abstract: A lens apparatus attachable to an image pickup apparatus includes a first optical system, a second optical system, and a driving unit that moves at least one of the first optical system and the second optical system in an optical axis direction. The lens apparatus is configured to switch between a first driving mode for performing autofocus by moving both the first optical system and the second optical system in optical axis directions of the first optical system and the second optical system via the driving unit, and a second driving mode for adjusting a difference in imaging position for a same object image between the first optical system and the second optical system by moving the at least one of the first optical system and the second optical system in the optical axis direction via the driving unit.

Abstract: A lens apparatus includes a lens mount to which a camera body is attached, a mount cover provided at the lens mount, a filter, and a filter holding member that holds the filter. The filter holding member is attachable to the mount cover.

Abstract: A process for the production of fine powder of metallic nickel which comprises a first step of dissolving nickel carbonate and/or nickel hydroxide in aqueous ammonia or in an aqueous solution of ammonia and at least one selected from the group consisting of ammonium carbonate, ammonium hydrogencarbonate, a carbonate of an alkali metal and a hydrogencarbonate of an alkali metal to prepare an aqueous solution of a nickel salt; converting the aqueous solution of a nickel salt to a W/O emulsion, and then removing volatile components including ammonia from the droplets to form precipitates of nickel carbonate in the droplets, thereby providing fine spherical particles of nickel carbonate; and a second step of heating the particles of nickel carbonate in the presence of a fusion preventive agent that is a compound of at least one element selected from the group consisting of alkaline earth elements, aluminum, silicon and rare earth elements in an atmosphere of hydrogen, thereby reducing the nickel carbonate to meta

Abstract: The invention provides a process for production of fine spherical particles of a carbonate or a hydroxide of nickel, cobalt or copper which comprises: dissolving a carbonate or a hydroxide of nickel, cobalt or copper having the general formula (I) M(CO3)x/2.(OH)y wherein M represents Ni, Co or Cu, and x and y are numerals satisfying the followings: 0≦x≦2, 0≦y≦2 and x+y=2, in aqueous ammonia, converting the resulting solution to a W/O emulsion containing droplets of the solution in a non-aqueous medium, and then removing volatile components including ammonia from within the droplets, thereby precipitating a basic carbonate or a hydroxide of a metal selected from nickel, cobalt and copperin the droplets.

Abstract: A multilayer piezoelectric composite comprising a bonded laminate each layer of which is composed of a green sheet of a low-temperature sintering lead zirconate titanate piezoelectric ceramic. The temperature coefficient of a frequency constant of at least one layer has a polarity opposite to the polarity of those of the other layers. The bonded laminate is sintered at a temperature which does not produce any or almost any interdiffusion between layers so that the absolute value of the temperature coefficient of a frequency constant of the bonded laminate is smaller than the absolute value of the temperature coefficient of a frequency constant of any or one of the layers.

Abstract: A method of producing single crystalline, acicular .alpha.-ferric oxide particles of narrow particle size distribution is provided. The method comprises heating an aqueous suspension of ferric hydroxide at temperatures of 100.degree.-250.degree. C. at an alkaline pH in the presence both a water soluble organic or inorganic compound capable of forming complexes with iron as a growth regulating agent and .alpha.-ferric oxide seed crystals of minor axes not larger than 0.4 microns in average in amounts of 0.1-25 mole % in terms of the Fe content thereof in relation to the ferric hydroxide.

Abstract: Single crystalline, acicular ferric oxide particles are produced by maintaining an aqueous suspension of ferric hydroxide at an elevated temperature at an alkaline pH in the presence of an organic phosphonic acid compound or a hydroxycarboxylic acid compound as a growth-regulating agent.

Abstract: Single crystalline, ferrite particles are obtained by the thermal reaction of ferric oxyhydroxide, ferric hydroxide, porous ferric oxide made therefrom or ferric oxide having a particle size less than 0.8.mu. with a strontium or barium compound such as the oxide, hydroxide, the carbonate or the carboxylate in the presence of a small amount of a metal chloride flux such as strontium chloride or barium chloride.The resulting particles have a well-defined, hexagonal plate configuration and are particularly adapted for the production of anisotropic magnets.

Abstract: Single crystalline ferrite particles are obtained by the thermal reaction of ferric oxyhydroxide, ferric hydroxide, porous ferric oxide made therefrom or ferric oxide having a particle size less than 0.8.mu. with a strontium or barium compound such as the oxide hydroxide, the carbonate or the carboxylate in the presence of a small amount of a metal chloride flux such as strontium chloride or barium chloride.The resulting particles have a well-defined, hexagonal plate configuration and are particularly adapted for the production of anisotropic magnets.