Sexy In White

[DaveB]

Originally Posted by Carl Zaiss

Hey Dave...is she going to be one of the models at your December 9th lighting workshop? Nice work and I am looking forward to being with you again!
Carl

Nope. Sorry! You won't be disappointed though.

[Marty_McBride]

Most definitely sexy in white....Nice shot!!!

[R_Fredrick_Smith]

Originally Posted by gawie

I have found that my light meter says one thing, the histogram on my canon 30D says another!
Thanks.

There are many factors that are at play when using a light meter and/or a histogram. First, if you are using the light meter in the camera, then that will be a reflective reading of the scene and will often give you a different result than using a handheld incident meter at the subject position when then measures the light falling on the subject rather than the light being reflected by the subject as does the camera's meter. And if using the camera's meter its going to depend on whether you're using the evaluative mode, center averaging mode or partial mode.

The histogram will simply show you the distribution of tones being reflected from the subject and scene. A histogram is not an easy thing to work with if you don't take into consideration all the variables in the scene.

Try this test. Place a gray card at the subject position and shoot a photo of it where it fills the full frame on your 30D. You should see one spike in the middle of the histogram. If you don't, then the exposure is wrong. Adjust the exposure and shoot again until the spike is in the middle of the histogram. Now change over to manual mode and set the same fstop and shutter speed used to get the spike to the middle of the histogram.

Now shoot a photo of a black card at the same position as the gray card. Be sure you have it full frame. Examine the histogram. You should see a big spike towards the left side of the histogram. Now do the same experiment with a white card. You should see a big spike on the right side of the histogram.

At this point your manual setting is properly set to shoot the scene and get a good exposure of your model. But suppose the model is black, or suppose she is very fair skinned. Will that change the exposure. Naturally it will because of the reflectance value of black and white.

Now use he camera's meter to find out what exposure it would suggest for the Black card (full frame). It will be quite different than the manual setting you used. That's because the meter will try to make the card 18% gray. Same thing for the white.

What is the moral of this story? You need to meter on something that is a mid-tone and then adjust up or down based on the what you want properly exposed in the photo. If its a model's skin tones, then you adjust accordingly.

To use the histogram to evaluate whether you are close, you usually need to use a calibration target of some sort. Here is an example:

Meter and Histograms 

When you photograph that target full frame, you are trying to get an exposure that gives you three spikes just as shown in the example histogram. When you have three full spikes, then you know you have a good exposure. You then want to calibrate your meter to what the histogram is showing you.

You can read more about how to use a target like this on the PhotoVision site.

Cheers,
rfs