Een split-focus-screen heeft geen invloed op de lichtmeting van de camera.
Sorry, Ruurd, maar niet helemaal correct. De makers van de splitscreens zeggen er zelf het volgende over:
Will a KatzEye™ Focusing Screen Affect My Light Meter?Whenever one introduces a prism into the light path of the camera, there is always the possibility the camera’s light meter will be affected to some degree. We have done our best to summarize the effects on the page for each camera model, but if you need clarification or more information, please feel free to contact us.
How Can I Minimize Light Metering Errors?This varies quite a bit in different camera models, so please refer to the page for your camera model for specific answers. In general however, metering modes that use the entire frame, such as centerweighted average metering and full frame evaluative metering have the most accurate results. Metering modes that weight the center portion of the scene heavily, such as partial metering, spot metering, and some manufacturers’ evaluative metering will be most affected. Fortunately, with the availability of on-demand histograms, it is generally a simple matter to take a test shot, check the histogram, and adjust the exposure compensation accordingly. The exposure shift is generally constant for a particular lens (when using auto-aperture lenses), so once the necessary compensation is known, it can be set with each lens change. Again, for more specific answers, please refer to the product description for your camera model.
Metering Information
The KatzEye™ focusing screen for the Pentax K-5 and K-7 shows only a very slight effect on light metering. In our testing, the KatzEye™ screen tested within factory tolerance in nearly all situations. The only exception is when using spot metering with lenses having apertures of f2.8 or smaller. This combination may produce overexposure, so it is advisable to use either center-weighted average metering or multi-segment metering to preserve accurate meter response when using small aperture lenses. In the event that spot metering mode must be used with a small aperture lens, it is advisable to set an appropriate exposure compensation by reading the histogram of a test shot. Approximate exposure compensation values are as follows*: (en hier volgt een tabel waaruit blijkt wat de vereiste belichtingscompensatie moet zijn)
Note: These exposure compensation suggestions are a recommended starting point only and actual results may vary depending on conditions. Users are advised to take a test photo and check the histogram before beginning any critical work. Apertures indicated in the above chart are the lens maximum aperture as indicated on the lens body and are not affected by the actual aperture chosen for a given photo.
* Metering test results presented are based on testing of the K-7 model. While results are expected to be similar for the K-5, users of this model are strongly encouraged to take a test shot and check the histogram before beginning any critical shooting.
PS: Hetzelfde geldt natuurlijk voor andere cameramodellen en er zijn specifieke correctiewaarden voor ieder model beschikbaar.
Topic: Lichtmeting camera beinvloed door split-focus-screen? (gelezen 1858 keer)