Thread: lux, lumens, different and meters and so on

Results 1 to 3 of 3
  1. #1 lux, lumens, different and meters and so on 
    I found some different infos on different brands/products, so I would like to know which relations exist between these light measures.
    So, let's say I have:
    16000 lux @1m with 20 spot
    how many lux @3m or 5m with the same spot?
    how many lux @1m with 60 spot?
    Is it possible to determine the lumens?

    I found this site with some calculators:

    but I don't get consistent result.
    For example, I can determine how many lumens from lux, and m
    but if I reuse the lumens I obtained (that should remains unchanged with distance if I understood well), I got some lux at different distance that aren't the same as declared by the brand...

    Any help?
    Reply With Quote  

  2. #2  
    More, if I have 2 led lights, one -20% lux than the other, if the more powerful is 160W (equivalent about 1600W), the second one is about 1280W equivalent?
    Reply With Quote  

  3. #3  
    I found one site that partly confirms the above calculator:
    Calculating lumens from one lux@m@ then reapplying the lumens with different distance you find the correct value.
    That is the same of using the inverse square formula... as here:

    BUT if you reuse the same lumens with different spot and distance... it doesn't match. So it seems lumens change also with spot angle...
    I thought they were fixed with a certain power, the lux changes with spot and distance.
    So, how to determine lux with different spot angles, starting from one fixed data at certain angle and distance?

    In this site instead the numbers are a lot different also using the inverse square formula:

    You can't match even mantaining the same spot, changing only the distance: crazy, how they got those numbers??

    Here, at Aputure they don't even put the spot angle:
    How many angle to get those lux at spot?? Giving lux and distance without angle it's notsense.

    A jungle...
    Reply With Quote  

Similar Threads

  1. Light meters for Black magic
    By ChristianHubbard in forum Cinematography
    Replies: 30
    Last Post: 11-11-2016, 01:21 AM
  2. On-screen audio level meters
    By carlmart in forum General Discussion
    Replies: 25
    Last Post: 06-28-2014, 09:25 PM
  3. Replies: 6
    Last Post: 11-19-2013, 07:17 PM
  4. SDI Monitor with meters
    By mbeck in forum General Discussion
    Replies: 38
    Last Post: 09-09-2013, 04:16 PM
  5. audio meters
    By ryaninoz in forum General Discussion
    Replies: 10
    Last Post: 05-01-2012, 02:21 PM
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts