DE312806C

DE312806C -

Info

Publication number: DE312806C
Application number: DE1918312806D
Authority: DE
Priority date: 1917-12-15
Filing date: 1918-03-02
Publication date: 1919-06-10
Also published as: CH79346A; AT83522B

Description

Bei einem bekannten optischen Belichtungsmesser ist unmittelbar vor oder hinter dem Objektiv ein Schieber oder Band mit einer abgestuft lichtdurchlässigen Schicht und einer Zeitskala verschiebbar angeordnet. Derartige Belichtungsmesser haben den Nachteil, daßdie Lichtstrahlen durch sie hindurchgehen müssen-, wodurch sie gebrochen werden und ein verzerrtes Bild hervorbringen. Das BildIn a known optical light meter is immediately in front of or behind the Objectively a slider or band with a graduated translucent layer and a Time scale arranged to be movable. Such exposure meters have the disadvantage that the Rays of light have to pass through them - thereby refracting them and producing a distorted image. The picture

ίο wird nicht durch den Belichtungsmesser hindurch betrachtet, sondern durch ihn nur mehr oder weniger verdunkelt. Demzufolge kann. er nicht zugleich als Mattscheibe dienen, so daß man sich bei der Belichtungsmessung beider zu bedienen hat. Bei Anbringung des Belichtungsmessers hinter dem Objektiv muß zur Ablesung der Zeitskala die Mattscheibe weggenommen werden und trotzdem ist die Ablesung erschwert und unsicher, da die Skalaίο will not get through the light meter viewed, but only more or less obscured by it. As a result, can. it does not serve as a focusing screen at the same time, so that you can measure the exposure of both has to use. When attaching the exposure meter behind the lens must be Reading of the time scale the ground glass can be removed and the reading is still difficult and insecure because of the scale

a.o im Innern der Kammer liegt.a.o. lies inside the chamber.

Gemäß der Erfindung wird das beim Objektiv nicht verdunkelte Bild nach einander durch die abgestuft lichtdurchlässigen Felder betrachtet und der Grad der Lichtdurchlässigkeit, bei dem das Bild beim Betrachten durch die Felder unsichtbar wird, als Maßstab für die Belichtungszeit benutzt. Der Belichtungsmesser gemäß der Erfindung besitzt neben den bekannten abgestuft lichtdurchlässigen Feldern ein mattiertes aber helles, als Mattscheibe dienendes Feld und liegt in der Bildebene des Apparates. Mittels dieses Belichtungsmessers kann die Belichtungsdauer auf einfache.According to the invention, the image not darkened by the lens is successively viewed through the graduated translucent fields and the degree of translucency, in which the image becomes invisible when looking through the fields, as a yardstick for the Exposure time used. The light meter according to the invention has besides the well-known graduated translucent fields a matt but light one as a matt screen serving field and lies in the image plane of the apparatus. Using this light meter can set the exposure time to simple.

rasche und sichere Weise bestimmt werden und hat der Beobachter die Zeitskala unmittelbar vor Äugen. Bei Rollfilmapparaten ist der Belichtungsmesser mit dem Rollfilm verbunden.can be determined quickly and reliably and the observer has the time scale immediately before eyes. In roll film devices, the exposure meter is connected to the roll film.

Bei einer Reflexkamera würde die zur Belichtungsmessung in Frage kommende Bildebene die Reflexebene sein.With a reflex camera, this would be used to measure the exposure the image plane in question may be the reflex plane.

In der Zeichnung ist beispielsweise als Ausführungsform einer zur Ausführung des Verfahrens dienenden Vorrichtung ein Mattscheibenfilm dargestellt ■. In the drawing, for example, a screen film is shown as an embodiment of a device used to carry out the method .

Das in der Zeichnung veranschaulichte, auf eine nicht dargestellte Spule aufzurollende FiImbänd ist in mehrere Felder eingeteilt. Das erste Feld M ist matt aber hell und dient als Mattscheibe, während die folgenden, mit den Bezeichnungen »3 Sekunden«, »2 Sekunden«, »1 Sekunde« und B¹Z₂₆ Sekunde« versehenen Felder ebenfalls matt sind, aber eine von Feld zu Feld zunehmende Dunkelheit aufweisen, was in der Zeichnung durch Schraffuren angedeutet ist. Am Ende des Filmbandes ist ein gummiertes Papier GP angebracht, welches dazu didnt, den Mattscheibenfilm mit einem photographischen Rollfilm R F zu verbinden. Statt des gummierten Papieres könnte auch irgendein anderes Mittel am Ende des Mattscheibenfilms angeordnet sein, welches geeignet ist, eine Verbindung mit dem photographischen Rollfilm herzustellen.The film illustrated in the drawing to be rolled up on a reel, not shown, is divided into several fields. The first field M is matt but light and serves as a ground glass, while the following fields labeled "3 seconds", "2 seconds", "1 second" and B ¹ Z ₂₆ seconds "are also matt, but one of Show field to field increasing darkness, which is indicated in the drawing by hatching. At the end of the film tape a gummed paper GP is attached, which didnt connect the screen film to a photographic roll film RF . Instead of the gummed paper, some other means could also be arranged at the end of the focusing screen film which is suitable for producing a connection with the photographic roll film.

Mit dem beschriebenen Mattscheibenfilm vollzieht sich das Verfahren zur Ermittlung der Belichtungszeit wie folgt:The procedure for determining the Exposure time as follows:

(2. Auflage, ausgegeben am 4- August 1919J(2nd edition, issued on August 4, 1919J

Claims

A camera containing the matte film is focused on the object to be photographed using the matte field M. The different dark fields of the focusing screen film are then placed in sequence in place of the focusing screen field M, always while observing the image created by the lens. If the image becomes invisible in one of these fields, then in this field the exposure time corresponding to the brightness of the object, e.g. B. "i second", read off. The great advantage of the invention is that to determine the exposure time, instead of more or less unreliable scales or tables on the time of year and day, cloud cover, etc., an empirical means that works with certainty for the individual exposure case, instead of the previous exposure meters is applied, which excludes estimates of the degree of illumination which are easy to error and is very simple to set up and use. In the case of plate apparatus, in order to determine the exposure time, instead of the ground glass, framed foils made of celluloid etc. of various degrees of darkness adjusted to certain exposure times can be inserted one after the other into the apparatus. Or a pair of winding rollers can be attached to a screen frame and on the same a film divided into several fields, one of which fields one is light, while one of the other fields is always darker than the previous one, attached and as close as possible to the image plane , be movable. For the stated purpose, foils of the same degree of darkness can also be inserted one after the other in the ground glass frame between the ground glass and a glass plate and the exposure time can be determined from the number of these, foils. P A T E N T - A N S F R Ü C H E:

1. Method for optical exposure measurement using graduated translucent Fields, characterized in that one after the other through the image that is not darkened in the lens the graduated translucent fields and the translucency, at . which the picture becomes invisible when looking through the fields, as a yardstick for the exposure time used ..

2. Optical light meter with graduated, graduated translucent fields, thereby marked that the film provided with these fields is a matt but light, as a ground glass serving field and in the image plane or reflex plane of the Apparatus is arranged.

3. Optical exposure meter according to claim 2, characterized in that it ■ is connected to a photographic roll film.

4. Optical exposure meter according to claim 2, characterized in that it on rollers attached to the left and right of a ground glass frame and in the image plane or reflex plane of one roller to the other is displaceable.

5. The method according to claim 1, characterized in that individual fields different light transmittance one after the other in the image plane or reflex plane of the apparatus begins and looks at the image through it. .

6. The method according to claim 1, characterized in that characterized in that one simultaneously has two or more fields of the same light transmission one after the other in the image plane or reflex plane of the apparatus and looked at the picture through them.

1 sheet of drawings.