DE1020232B - Device for automatic display of the depth of field on photographic lenses - Google Patents

Description

GERMAN

The invention relates to a device for automatic Display of the depth of field on photographic lenses in spiral mount, which are used for reading the respective distance setting wear a scale carrier with a corresponding graduation.

The depth of field defines an area in front of and behind the set distance value that is still sufficiently sharp. The size of this area depends on a constant unsharp circle diameter on the focal length and the relative aperture of the lens. The depth of field is larger for lenses with a shorter focal length and decreases with a decrease in the relative Opening to. With a given focal length, the depth of field can therefore vary with the diaphragm will. It is advantageous if the size of the depth of field range is read off for each aperture value can be.

Various solutions have already been proposed for this purpose. So were z. B. the Depth of field ranges for the individual apertures indicated on an additional scale or by colored ones Markings marked. On a special ring that is attached to the Worm gear is attached, the individual areas of focus can be relative to the corresponding Openings are engraved. This arrangement only permits accurate readability of the Depth of field values, because often - especially with photographic lenses with a long focal length - the individual intervals are very close together. The clarity of the depth of field is not there either given where the distance division is carried out without reference lines.

For a better display and to make it easier to read the depth of field was at Optical systems in so-called central locks have also already been proposed in or on the lock body a rotatable control element arranged centrally to the optical axis for the aperture setting and to provide two rings running in opposite directions with pointers visible on a distance scale. One same device for lenses: in worm gear mount is due to patent application Sch 10721 IX a / 57 a became known, according to which a curve arranged centrally to the optical axis for Control of the two counter-rotating pointer rings by means of a rack gear is used.

The invention relates to a further improvement of such devices of the latter type to the Display and reading of the respective displayed depth of field on the distance scale through contrast effect to make it clearer, and also to carry out the overall structure so that the

Device for automatic

View the depth of field

on photographic lenses

Applicant:

Jos. Schneider & Co. Optical Works,
Bad Kreuznach (RhId.)

Karl Heinz Schütz, Bad Kreuznach (RhId.),
has been named as the inventor

Outer frame as closed as possible and therefore dust-tight can be held. This is achieved in that the rotatable adjusting ring consists of a ring clear or translucent material with the distance scale.

^a 5 Furthermore, the invention consists in that the opposing rotating rings carry segment-shaped cover surfaces and these cover the distance scale more or less laterally by the control member below the transparent distance scale according to the respective aperture setting. For better. The displayed values can be recognized by a further, preferably colored, contrasting ring below the transparent rotating ring with distance scale and below the cover surfaces.

According to the invention it is also provided that the rotating rings carrying the cover surfaces by means of a gear and a pinion are driven, in which one of the control cam resiliently adjacent Gear segment engages.

The drawing illustrates an embodiment of the subject matter of the invention, wherein

Fig. 1 is a longitudinal section through a new lens mount partial view,

Fig. 2 shows a cross section along line H-II of FIGS. 1 and

Fig. 3 shows a development of the control elements.

It means 1 a bayonet connection piece, 2 the rotatable control member with a rising or falling curve 2b in the direction of the optical axis for the depth of field adjustment, wherein, for example, a second curve 2a for a - not shown - device for diaphragm

709 807/153

Claims (4)

preselection can be provided on the same control element, which is held in the socket 1 by a threaded ring 3 and - together with a ring 5 - can be adjusted by an adjusting cam 6 in the same direction of rotation. The ring 5 bears the diaphragm division 7 "(FIG. I)" on the outer circumference, which is visible in a window 8. One by one. Pin 9 a swingable toothed segment 9 engages in a pinion 10 a, which is rotatably mounted with an equiaxed gear 10 in a bracket 10 b. A spring 12 presses the toothed segment against the curve 2 b (Fig. 3). 13 is one and "14 is the second rotating ring with incorporated tooth pitches 13 a and 14 a. Part-circular cover surfaces 15 and 16, which are preferably colored, for example red, are connected to the rings 13 and 14. The distance setting ring 17 is connected to the worm gear 18 by intermediate rings 17 a, 17 & and carries a ring 19 made of transparent or translucent material, e.g. plexiglass, with the spacing 19 a, which is visible through a window 20 a in the casing 20 21 denotes the ball-bearing diaphragm grooved ring with the diaphragm blades 22 and 23 the lens mount body, which can be axially displaced in a known manner through the worm gear 18. 24 is a contrasting ring arranged under the transparent scale ring 19, 19 a and below the cover surfaces 15, 16, which may be colored, The mode of operation of such a device according to the invention is as follows: By turning the adjusting cam 6 in the direction of of arrow A (Fig. 2) the ring 5 with the diaphragm division 7 is set to the desired diaphragm value visible in window 8. Thus, at the same time, the control member 2 is moved in the same direction of rotation and by means of the curve 2b, the tooth segment 9 is rotatably adjusted against the action of the spring 12 (Fig. 3). The pinion 10a engaging in the toothed segment 9 rotates the gearwheel 10 in the direction of the arrow, which in turn adjusts the two rotating rings 13 and 14 radially to the optical axis of the lens against each other by engaging the tooth profiles 13a and 14a, according to FIG . 3 to approximately in the dotted position of the (colored) cover surfaces 15 and 16. This - or the reverse - counter-rotating movement of the rotating rings 13 and 14 is by means of the cover surfaces 16 and 16 in the window 20 a of the shell 20 below the transparent ring 19 outside made visible in order in this way to display the corresponding depth of field range directly at the distance graduation a, the visual effect being enhanced by the "mentioned (colored) contrast ring 24. With such a device according to the invention, only the aperture is set to the respective desired value, whereby the setting of the depth of field indicator - conditional t through the joint control - inevitably and automatically. Ρλ τ ε ν τ α ν s ρ r (I c η ε: 1. Device for the automatic display of the depth of field on photographic lenses in a worm gear mount by a rotatable control element arranged centrally to the optical axis for two opposing rings to display the respective depth of field on the distance scale, characterized in that the rotatable setting ring (17, 17 a, 17 b) a ring (19) made of transparent or translucent material, e.g. B. Plexiglas, with the distance scale (19 a) carries. 2. Device according to claim 1, characterized in that the counter-rotating rotating rings (13 and 14) carry segment-shaped cover surfaces (15 and 16) and these by the control member (2.2 b) below the transparent distance scale (19α) according to the respective aperture setting Cover the distance scale more or less on the side. 3. Device according to claims 1 and 2, characterized in that under the transparent Rotary ring (19) with distance scale (19 a) and below the cover surfaces (15, 16) a further, preferably colored contrasting ring (24) is arranged. 4. Device according to claims 1 to 3, characterized in that the cover surfaces (15 and 16) bearing rotating rings (13, 14) by means of a gear wheel (10) and a toothed pinion (10 a) are driven, into which a toothed segment (9, 9 a) resting resiliently on the control cam (2Ji) intervenes. 1 sheet of drawings © 709 807.153 11.57