LED-How to tell the real ligthing output of led lights?How to compare lighting power?

haringharing Major grinsPosts: 279Registered Users Major grins
edited January 20, 2016 in Accessories
I am looking at several led light options. Obviously, one of the considerations is how much light the led panel emits.
Some companies list their products specifying out put via "lux"
http://www.adorama.com/fpvl500c.html
Others list Watt, W.
http://ikancorp.com/productdetail.php?id=998
Others use lumens...

My questions: How to measure/compare the lighting output of led lights? Is there a way to convert these numbers? All I want to know how much light these lights output so I can compare them.

Comments

  • mercphotomercphoto Bill Jurasz Posts: 4,550Registered Users Major grins
    edited January 13, 2016
    Watts are meaningless for this purpose. That measures electrical power consumption, that's it. Its very useful to know, as it dictates battery life, or how big an A/C circuit you need, expected heat generation, etc. But tells you nothing about how efficiently the lighting devices turns electricity into photons.

    In terms of light power output its all about lumens.
    Bill Jurasz - Mercury Photography - Cedar Park, TX
    A former sports shooter
    Follow me at: https://www.flickr.com/photos/bjurasz/
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  • ziggy53ziggy53 Still learnin'still lovin Posts: 20,935Super Moderators moderator
    edited January 13, 2016
    Ideally I would want to know both lumens and lux because one lux is equal to one lumen per square metre. Then you also need to know the lux at a couple of distances from the source in order to ascertain light spread.

    In other words, if all the manufacturer is giving you is either lumens or lux, and if they don't define how they arrive at those figures, that is certainly not enough information to compare between manufacturers nor is it sufficient information about how the light will work at specific distances from the source. If all they give you is watt usage, steer clear because they are telling you nothing about light output at all (as Bill already said.)

    Find comparative reviews for more information and definitely purchase from a supplier with ample return privileges so that you can test suitability in your application.

    I still cannot recommend LED lights for color accuracy, especially skin tone color accuracy, reds in general and many times specific blues as well. Make sure that you view a sample image of a photographic color chart lit by the particular light prior to purchase if color accuracy is important to your application.
    ziggy53
    Moderator of the Cameras and Accessories forums
  • SamSam San Jose CA Posts: 7,418Registered Users Major grins
    edited January 14, 2016
    I just looked at Einstein, and Profoto, nether one had lumen or lux specs.

    All they had was watt seconds, temp, flash duration.

    These are both good quality reliable manufacturers?? Just saying....................

    Sam
  • dbddbd Fool on the hill Posts: 216Registered Users Major grins
    edited January 19, 2016
    Sam wrote: »
    I just looked at Einstein, and Profoto, nether one had lumen or lux specs.

    All they had was watt seconds, temp, flash duration.

    These are both good quality reliable manufacturers?? Just saying....................

    Sam

    Paul C Buff Inc gives a table of 10' and 5' required F stop and the guide number (all at 100 ISO) at a wide range of power levels after you select the light modifier for it's products at http://www.paulcbuff.com/output.php.

    Profoto provides the required F stop at 2 M at 100 ISO for a selection of light modifiers at a specified power level (Ws) in the technical data section of the product data sheets.

    Just saying...???

    Dale B. Dalrymple
    "Give me a lens long enough and a place to stand and I can image the earth."
    ...with apology to Archimedies
  • ziggy53ziggy53 Still learnin'still lovin Posts: 20,935Super Moderators moderator
    edited January 20, 2016
    dbd wrote: »
    Paul C Buff Inc gives a table of 10' and 5' required F stop and the guide number (all at 100 ISO) at a wide range of power levels after you select the light modifier for it's products at http://www.paulcbuff.com/output.php.

    Profoto provides the required F stop at 2 M at 100 ISO for a selection of light modifiers at a specified power level (Ws) in the technical data section of the product data sheets.

    Just saying...???

    Dale B. Dalrymple

    Yes, these are the types of data important to a true photographer. thumb.gif
    ziggy53
    Moderator of the Cameras and Accessories forums
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