PetaPixel

FilterCalc: An Android App for Calculating the Exposure Offsets of Filters

Still shoot film? Use filters when you shoot? FilterCalc is a new Android app that’s designed to help non-TTL photographers figure out proper exposure when using filters.

This base ISO exposure calculator comes with preloaded database of almost 500 filters. By selecting the actual ISO value and filter type, the app computes base ISO to be used with the light meter resulting in proper exposure.

FilterCalc can compute ISO compensation in increments of 1/3, 1/2, 2/3 and full stop EV. You can select compensation values by stops, by filter factor, by preloaded filter brand/type, or add your own custom data.

The app is free and can be downloaded over on Google Play.

FilterCalc [Google Play]


 
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  • will hall

    forgive my ignorance if im wrong, but would the compensation not depend on the scene? If you’ve got a yellow filter and a scene that’s mostly yellow most of the light will get through, if your scene contains no yellow hardly any will get through so much more exposure compensation is going to be needed surely?

  • skymyrka

    Hey, Will:
    Generally, number of stops/filter factor is constant. There is a small
    subset of filters that have varying compensation value on daylight vs
    tungsten. For example, Yellow 2 and 3 filters are usually reduced by
    1/3 stop in tungsten light. All that information is usually provided by
    the filter manufacturer.

    If you’re looking to “block out” certain light wavelengths there’s
    specialty filters for that (e.g. infrared and UV-A photography filters).

  • http://twitter.com/ralphhightower Ralph Hightower

    Hmm, I like the idea of this app, but my camera, Canon A-1, has through the lens metering, so the filter factor is already taken into account. Yea, I would like a handheld meter (spot, ambient, and flash) and I could see where the utility of this app comes into play.
    This is for B&W Contrast filters: filters pass through complementary colors. A yellow filter darkens the sky and punches up the clouds; orange is more intense, and red makes the sky darker.