Abstract: A lens holding frame holding a lens in a lens barrel is arranged, and a contact member extending therebelow is in friction coupling with a driving axis. By applying driving pulses having such a waveform that includes a moderate rising portion followed by an abrupt falling portion to a piezoelectric element, the holding frame is moved along the direction of the optical axis. An index provided at the holding frame is exposed through a slit of lens barrel, and from the position of the lens on the holding frame, information with respect to the distance to the object is displayed. Detection of the position of the holding frame is performed by a position sensor of ferromagnetic thin film magneto-resistive element type (MR sensor) so as to obtain positional information of the lens on the holding frame based on the detection signal, and the obtained information may be displayed on a liquid crystal or other display portion provided on the lens unit or on a camera body.

Abstract: A lens holding frame holding a lens in a lens barrel is arranged, and a contact member extending therebelow is in friction coupling with a driving axis. By applying driving pulses having such a waveform that includes a moderate rising portion followed by an abrupt falling portion to a piezoelectric element, the holding frame is moved along the direction of the optical axis. An index provided at the holding frame is exposed through a slit of lens barrel, and from the position of the lens on the holding frame, information with respect to the distance to the object is displayed. Detection of the position of the holding frame is performed by a position sensor of ferromagnetic thin film magneto-resistive element type (MR sensor) so as to obtain positional information of the lens on the holding frame based on the detection signal, and the obtained information may be displayed on a liquid crystal or other display portion provided on the lens unit or on a camera body.

Abstract: A color measuring apparatus including a photoelectric conversion device for outputting basic color signals corresponding to quantities of light of basic color components of a sample, respectively, a calculating device for calculating a color value of the sample in a predetermined colorimetric system, a target setting device for setting a target color value of the sample in the predetermined colorimetric system, a region setting device for setting a predetermined region containing the target color value, a region decision device for deciding whether or not the color value falls within the predetermined region, an approximation decision device for deciding whether or not the color value has most approximated to the target color value and an output device for outputting a result of the decision of the approximation decision device.

Abstract: A photoelectric colorimeter which comprises a photoelectric conversion section including an optical filter to analyze light coming from a test piece and a reference calibrating sample into primary color elements, and a photosensor to convert each of said primary color elements into an electric signal; and a data processing section including a calibration constant calculating device for calculating a calibration constant for each of a plurality of reference calibrating samples on the basis of a calibration point of each of the reference calibrating samples and an information inputted from said photoelectric conversion section, a chromaticity point calculation device for calculating a chromaticity point of the test piece and that of each reference calibrating sample, a memory device for memorizing the calibration constant and calibration point of each of the reference calibrating samples, a device for estimating a new calibration constant suitable for the chromaticity point of the test piece between the respect

Abstract: Dehydrating decomposition of compound (I), i.e. gem-diol, hemi-acetal or hemi-ketal, by contact with sulfuric acid gives a carbonyl compound (II). ##STR1## Disclosed is a two-stage process in which the first stage is the contact of compound (I) with sulfuric acid at 90.degree.-140.degree. C. so as to partly decompose and dehydrate the compound (I), permitting the concentration of sulfuric acid to become lower than 93 wt. % but not lower than 65 wt. %, and the second stage is the contact of the product of the first-stage reaction with concentrated sulfuric acid at a temperature not higher than 60.degree. C., preventing the concentration of sulfuric acid from becoming lower than 93 wt %. For example, hexafluoroacetone is obtained from a hydrate thereof by this process using only a small amount of sulfuric acid.

Abstract: Crude hexafluoroacetone (HFA) hydrate containing chlorofluoroacetone(s) hydrate(s) as impurity is purified by adding an alkali metal hydroxide and maintaining at an elevated temperature, preferably at 100.degree.-110.degree. C., to thereby cause decomposition reaction of every chlorofluoroacetone hydrate with the alkali metal hydroxide, followed by neutralization of an excess portion of the alkali metal hydroxide. Alkali metal hydroxides, which readily react with anhydrous HFA, react preferentially with chlorofluoroacetone hydrates but hardly react with coexisting HFA hydrate.