In the old days professional photographers could be found using a light meter, to make sure the exposure they set manually on their camera would be right. Today I hardly ever see this: thus far only on weddings you occasionally see this. But the need to do read the environment light is still important and the best light meter we have at hand is in the camera !
Circumstances for measuring light are sometimes tricky. Outside, in changing weather, light changes constantly.
So how could we use our camera to come with a base setting for the camera ? I learned this method on one of the photographic tours I attended, hosted by Arthur Morris.
This is what you do:
- turn your back to the sun
- point your camera 30 degrees up in the sky
- dial your camera program to manual
- dial shutter speed/aperture until your meter reads a +2EV to +3EV reading, this setting will depend per camera
- with these settings, take a picture of a neutrally coloured object (e.g. a middle green bush) and check the histogram
- correct your exposure accordingly, so that your histogram shows a nicely distributed light profile
This exposure is your base setting for the sampled light circumstances. If the weather is constant, this setting is your base setting for a good half hour: then you recalibrate the light. If the weather is changing (partly cloudy), take a light sample for when the sun is covered and note this reading. Switch to and from this setting, depending on the light circumstances.
Since this is a base light reading, you now have to apply additional exposure corrections, depending on the (light/color) nature of your subject. If your subject is black, your should dial additional +1/3 to +2/3 to your exposure, to draw more details in the darks. If your subject is white, your should subtract -1/3 to -2/3 from your exposure, to prevent overexposing (and therefor losing details) of the whites. If your subject is ‘pied’ your exposure would likely stay in the middle, but usually a slight substraction correction is needed.
Remember to always shoot in RAW format, so that your could correct the exposure in either your camera processing software (e.g. Canon DPP) or in Photoshop ACR. If you shoot in JPEG, lost details are lost forever.