using a light meter outdoors

Discussion in 'Beyond the Basics' started by photosoto, Jan 26, 2012.

  1. photosoto

    photosoto TPF Noob!

    Joined:
    May 17, 2009
    Messages:
    202
    Likes Received:
    1
    Can others edit my Photos:
    Photos OK to edit
    I was considering buying a light meter eventually and I understand how to use the light meter to get the 'correct' exposure for flash, but how do you incorporate the ambient light as well? For example, what if I wanted the background to be underexposed but get the 'correct' exposure for the subject? adjust to a faster shutter speed and compensate with a larger aperture?


     
  2. Josh66

    Josh66 Been spending a lot of time on here!

    Joined:
    Oct 31, 2007
    Messages:
    14,604
    Likes Received:
    1,238
    Location:
    Cedar Hill, Texas
    Can others edit my Photos:
    Photos NOT OK to edit
    Most light meters will tell you the ambient-to-flash ratio.

    For example, it might say that with the current settings, the exposure would be 80% flash, 20% ambient. Then you just adjust the settings to get that ratio where you want it.
     
  3. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

    Joined:
    Dec 16, 2003
    Messages:
    33,901
    Likes Received:
    1,862
    Location:
    Edmonton
    Can others edit my Photos:
    Photos NOT OK to edit
    A hand held meter can be great for getting your exposure just right for your subject, whether it's flash or ambient light. The key is that is measures incident light (the light falling on the subject) not reflected light (the light reflecting off of the subject).

    But many light meters can also be used to measure reflected light, good for measure the background. But your camera has a built-in 'reflected light meter' so you could just use that for the background.

    In your example, you could aim the camera at the scene/background and adjust your settings until the meter reads -1.
    Now you can use your flash meter to test your flash's output. Dial in the ISO that is on the camera (on the meter) and adjust the flash power or distance until the reading until the meter gives you the same aperture that the camera is set to. That should give you a properly exposed subject (from flash) and a background that is one stop underexposed.

    But yes, if you need to adjust the ambient part of the exposure, then you can use the shutter speed because it won't affect the flash exposure.
     
  4. photosoto

    photosoto TPF Noob!

    Joined:
    May 17, 2009
    Messages:
    202
    Likes Received:
    1
    Can others edit my Photos:
    Photos OK to edit
    thanks for the great responses.... any suggestions on a light meter? There are so many things that I want to buy for photgraphy but I think a light meter is going to be a necessity. Getting the right exposure shouldn't be a continual crapshoot.
     
  5. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

    Joined:
    Dec 16, 2003
    Messages:
    33,901
    Likes Received:
    1,862
    Location:
    Edmonton
    Can others edit my Photos:
    Photos NOT OK to edit
    The most commonly recommended these days, seem to be the Sekonic meters.

    The basic flash/ambient model is (I think) the L308S. It should be enough for most people, but it lacks a few features of the next model up, the L-358...which seems to be the one that most people choose.
     
  6. 2WheelPhoto

    2WheelPhoto TPF Noob!

    Joined:
    Apr 14, 2011
    Messages:
    6,844
    Likes Received:
    994
    Location:
    Tampa
    Can others edit my Photos:
    Photos OK to edit
    I use a 358. I love it when using combined flash/ambient outdoors especially. Not only does it provide the value of each type light, but it shows the ratio and if one or the other changes it changes ratio values.

    When i walk into a studio with this meter, I can instantly know what the lights are doing which beats popping off shots for me.

    Also, when setting up two or more lights I can easily find the difference in fstop values.

    I really enjoy my light meter!
     
  7. Rockadile

    Rockadile TPF Noob!

    Joined:
    Nov 13, 2011
    Messages:
    28
    Likes Received:
    1
    Would I have to close down the aperture if 1/200 shutter speed isn't enough to underexpose the background?
     
  8. gsgary

    gsgary Been spending a lot of time on here!

    Joined:
    Oct 31, 2008
    Messages:
    16,144
    Likes Received:
    2,965
    Location:
    Chesterfield UK
    Can others edit my Photos:
    Photos OK to edit
    No because your aperture controls the flash exposure, you need more flash power
     
  9. Rockadile

    Rockadile TPF Noob!

    Joined:
    Nov 13, 2011
    Messages:
    28
    Likes Received:
    1
    Is it the same in a non flash situation? Only shutter speed affect ambient exposure? Wouldn't something like f/2.8 at 1/200 be brighter than say f/8 at 1/200?
     
  10. gsgary

    gsgary Been spending a lot of time on here!

    Joined:
    Oct 31, 2008
    Messages:
    16,144
    Likes Received:
    2,965
    Location:
    Chesterfield UK
    Can others edit my Photos:
    Photos OK to edit



    When shooting flash and ambient you have to think about 2 exposures, ambient only there is 1 exposure so in your example if the ambient exposure was F4 1/200 one shot would be over exposed and one would be under exposed, here's an example wher flash and ambient are about equal

    [​IMG]

    [​IMG]
     

Share This Page

Search tags for this page
what sekonic light meter is best for outdoor photography
,
how to use light meter outdoors
,
light meter for outside
,
light meters for outdoor photography
,

using a light meter outdoors

,
using incident light meter outdoors
,
using incident light meter outsid
,
what type of light meter do i use to measure outdoor light