Metering mode#Spot metering
The spot meter (English: spot = point; spot exposure meter = eng: spot meter. ) Is a device from the photo technology. He is a special light meter, which allows the photographer to aim for the subject through a viewfinder and to identify the light value of a very limited range. Spot light meter work according to the principle of object measurement.
Operation
Spot light meter often have a selectable measuring angle of 1 ° to 5 ° or even 10 °. Apart from the necessary viewfinder they meet in the other handling the normal exposure meter. For professional light meter there are also special attachments that turn it into a full-fledged spot exposure meter.
The spot metering is also integrated in some higher-quality SLRs. The so -called spot metering area is located at many cameras in the center of the image and is usually marked by a marker in the focusing screen. The size of the field is approximately one to five percent of the size of the whole imaging surface.
With some camera models (eg Nikon ) the area around the currently active AF point display for spot measurement can be used, not just the center. It is thus possible to measure the exposure and at the same distance at the same point in the image. In action-packed motifs and high contrast can be an advantage. In concert photography, it is thus possible, for example exposure and removal matched to a person's face as it moves across the stage without having to tilt the camera.
Application
Compared to the integral or matrix metering offers spot metering with little additional effort and with some experience a much better control over the outcome. The spot measurement always requires the photographer before taking a decision about which part of the targeted subject for correct exposure is important. " Point and shoot " often leads to erroneous exposures when the small spot randomly covering a very dark or very bright area of the subject.
Exposure meters are set up on a reflectivity of about 18 percent, which corresponds to a medium gray (see gray card ). If the exposure is measured on areas of skin, usually an exposure compensation is necessary. The palms are - largely independent of skin color - about one stop brighter than a gray card, and can serve as a guide.
With spot metering, with spot in the center of the image is first targeting a detail of medium brightness (see above ) which is in the same light as the main subject, the camera manually then one or stores the reading in automatic cameras between, then aligns the camera to the desired size and then pulls the trigger. This process sounds complicated, it is not after some getting used to though.
With spot metering on any autofocus metering field AF point is manually selected, the ( above a face, for example, with exposure compensation, see ) is directed to an image- important detail. It is measured simultaneously at this point exposure and removal, and triggered without tilting the camera. It is important to select a suitable measuring field, as picture and build - depend on this approach it. This method can be more responsive to dynamic motifs ( concert photography, sports). However, depending on the appropriate image detail before recording any exposure compensation to adjust.
The spot metering is also a method to calculate the subject contrast and the resulting averages. This method according to the zone system has been described in detail by the famous landscape photographer Ansel Adams (1902-1984) and propagated. Some modern cameras with matrix or evaluative metering sit in evaluating the light conditions of this method, but can not handle any conceivable motive or automatically correct naturally.
Products
The spot meter from Minolta was used by NASA for the moon landing. Another well-known manufacturer is the German Gossen, also spot diameter of Pentax and Sekonic are common.