Ask Phil: A LumiDisk and L-308s Question

MAC Group’s Phil Bradon, Product Marketing Manager for Sekonic in the United States, will answer selected questions sent to him at

Alexandre Maller asked the following question:

I own a great L-308S, and I have a question. What is the exact purpose of the optional Lumidisc? Is it for a more directional measure in incident mode?

Hi Alexandre,

You’ve answered your question. To the meter, the white surface of the incident light receptor is the subject. The hemispheric-shaped Lumisphere approximates the 3-D nature of a face and reads light striking it from 180-degrees averaging what it “sees.” The flat disk allows the metering cell to only “see” light directly in front of the meter. It is used to determine the brightness of lights in a multi-light setup. This difference in brightness is the building blocks for lighting ratios. If the main light is two times brighter (f/8) than the fill light (f/5.6) the ratio is 1:2. The Lumidisc is also used to measure light falling on a flat surface light a painting or a green screen for video shooting.

Please get back to me if you have any other questions about Sekonic meters.

Best regards,
Phil Bradon

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4 Responses to Ask Phil: A LumiDisk and L-308s Question

  1. Fashion says:

    Thankyou for such informative post, hope we will get more from you. Regards.

  2. Wow, my question is on the blog, I’m very honoured! Thanks to Phil for his great and precise answer.
    I’ve just sold my 308-S and ordered the blue limited edition one!

    Thanks a lot to Sekonic and its great communication.

  3. William pinzon. says:

    hola soy william pinzón gaffer. Estoy interesado en comprar un exposimetro pero tengo la duda de cual comprar si el L 308 S. ó el 758c.
    Ya que yo trabajo con cine y televisión. 

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