Using a light meter...have I got the idea?

Bend The LightBend The Light Registered Users Posts: 1,887 Major grins
edited March 28, 2012 in Technique
I have a Shepherd Light Meter which I intend to use in the studio. I just want to be sure I am using it properly.

So, here is it:

7020705099_ff513132f7_o.jpg
How to use light meter small by http://bendthelight.me.uk, on Flickr

So, I decide to read the light coming directly from the studio light, and so set the meter to "incident" with the little dome covering the sensor.
I set the ISO, in this case to 100.
I press the flash button on the side which triggers the flash (I have it plugged in to the unit).
I read 2 LEDs.
I turn the dial to "2"
I read off the aperture below (in this case, f2). (measurements are given as 1/125 seconds for shutter)

If I have shutter at 1/250 I need to open up by a stop (which would mean going to f1.4?)
If I set the shutter at 1/60, say, I need to stop down by a stop (going to f2.8?)


So does that sound right? So what if I have 2 lights?

Another thing - what if I want to read reflected light? I set it to the reflected setting, but this time read the light coming from, say, a person's face. This would read a combination of more than one light?

Another question - If I make a measurement of the face, reflected light, and then make a reading of reflected light from clothing, for instance, and they are different...what do i set?

Hopefully there are some folks who can help...I HAVE read the manual, but the manual is about how to take readings, not what to take readings of, or why. :)

Comments

  • pathfinderpathfinder Super Moderators Posts: 14,694 moderator
    edited March 27, 2012
    Which meter is this? I can find images of the Shepherd Polaris ( and associated youtube videos for its use )) and also images of the SPD 100, and the Dual 5 but I do not see one with the dial in your image. Your meter is a flash meter as well as a light meter?

    If this is an incident and a reflected meter, in the studio I would skip the reflected meter, and use just the incident meter - it will be much more consistent, as whether your subject is black or white will make no difference in the readings whatsoever, and that is a very good thing.

    Shutter speed ( at less than your flash sync speed ) really makes no difference in the exposure by flash. If your ambient is fairly bright, then you may need to accommodate the ambient contribution as well. But in most studios, ambient is 4 stops darker than the flash exposure, so effectively does not contribute to the image.

    For studio flash, set your shutter speed at 1/200th or 1/160th and choose your aperture for the depth of field you desire, and adjust your flash output and distance to create the proper exposure for your chosen ISO.


    Or you can shoot a single frame of a Lastolite grey non specular reflector, and have a frame for a custom white balance, AND the proper exposure for your flash if you shoot the frame in Av mode. You should see a single spike dead centered in your histogram. When you see that, you know your exposure was absolutely correct with the settings your camera chose in Av mode. And the grey jpg you shot can create a precise custom white balance for your camera with the lighting the frame was shot with. A very neat trick!
    Pathfinder - www.pathfinder.smugmug.com

    Moderator of the Technique Forum and Finishing School on Dgrin
  • Bend The LightBend The Light Registered Users Posts: 1,887 Major grins
    edited March 27, 2012
    pathfinder wrote: »
    Which meter is this? I can find images of the Shepherd Polaris ( and associated youtube videos for its use )) and also images of the SPD 100, and the Dual 5 but I do not see one with the dial in your image. Your meter is a flash meter as well as a light meter?

    If this is an incident and a reflected meter, in the studio I would skip the reflected meter, and use just the incident meter - it will be much more consistent, as whether your subject is black or white will make no difference in the readings whatsoever, and that is a very good thing.

    Shutter speed ( at less than your flash sync speed ) really makes no difference in the exposure by flash. If your ambient is fairly bright, then you may need to accommodate the ambient contribution as well. But in most studios, ambient is 4 stops darker than the flash exposure, so effectively does not contribute to the image.

    For studio flash, set your shutter speed at 1/200th or 1/160th and choose your aperture for the depth of field you desire, and adjust your flash output and distance to create the proper exposure for your chosen ISO.


    Or you can shoot a single frame of a Lastolite grey non specular reflector, and have a frame for a custom white balance, AND the proper exposure for your flash if you shoot the frame in Av mode. You should see a single spike dead centered in your histogram. When you see that, you know your exposure was absolutely correct with the settings your camera chose in Av mode. And the grey jpg you shot can create a precise custom white balance for your camera with the lighting the frame was shot with. A very neat trick!

    Everything you say makes perfect sense, and I have found some of it out when asking on other fora. I think the grey card is next on my list...

    :)
  • Art ScottArt Scott Registered Users Posts: 8,959 Major grins
    edited March 27, 2012
    pathfinder wrote: »
    Which meter is this? I can find images of the Shepherd Polaris ( and associated youtube videos for its use )) and also images of the SPD 100, and the Dual 5 but I do not see one with the dial in your image. Your meter is a flash meter as well as a light meter?

    this looks very much like the Shepard FM1000 ... great accurate meter...or at least mine was ...

    EDIT...DAMN i was wrong...that is older than the FM 1000 ... that is actually an analog meter using leds instead of the needle....

    But it seems you are using correctly BendtheLight....
    "Genuine Fractals was, is and will always be the best solution for enlarging digital photos." ....Vincent Versace ... ... COPYRIGHT YOUR WORK ONLINE ... ... My Website

  • Bend The LightBend The Light Registered Users Posts: 1,887 Major grins
    edited March 28, 2012
    Art Scott wrote: »
    this looks very much like the Shepard FM1000 ... great accurate meter...or at least mine was ...

    EDIT...DAMN i was wrong...that is older than the FM 1000 ... that is actually an analog meter using leds instead of the needle....

    But it seems you are using correctly BendtheLight....

    I actually used it in anger last night. I was doing some portraits for use in a theatre programme. So I measured the light, set aperture accordingly, and the exposure was nice! Seems it works pretty well. :)

    6877074662_1ac59eeb96_o.jpg
    Ruby, Thomas, and Paige by http://bendthelight.me.uk, on Flickr
  • Art ScottArt Scott Registered Users Posts: 8,959 Major grins
    edited March 28, 2012
    very well done.

    a quick google search for your model might yield a manual for around $10 ...
    "Genuine Fractals was, is and will always be the best solution for enlarging digital photos." ....Vincent Versace ... ... COPYRIGHT YOUR WORK ONLINE ... ... My Website

  • Bend The LightBend The Light Registered Users Posts: 1,887 Major grins
    edited March 28, 2012
    Art Scott wrote: »
    very well done.

    a quick google search for your model might yield a manual for around $10 ...

    Well, I downloaded the manual of the 88, which is very similar. only thing missing for that one is the GN readouts...

    Managed to use it, anyway. :)
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