can somone help me understand exposure a little bit better?

Question

lets say its a nice sunny day and I am using 100 speed film with my camera set to shutter priority and its set for 1/125th of a second. I'm taking a picture of a solid WHITE wall..dont ask me why..and the aperture reads f16. Now, If I go ahaed and snap the picture, I would like someone to explain to me, in pretty understandable terms as to whether the pic will turn out under or over exposed..and why?? I am missing a key understanding of this concept and my pictures are sufffering because of it.

Thanks

Answer 1

If that is what your camera meter is reading most likely the photo will be underexposed. Typically when photographing excessive amounts of white you want to overexpose by at least 1.5-2 stops or if you do not have a overexposure compensation setting on your camera set the ISO to 32 if you are using 100 ISO film.
To understand why a cameras light meter will almost always underexpose an image with excessive white areas, you have to understand how cameras a light meter works. A camera's light meter is programmed to believe that the perfect photo is a middle gray color. So when you point your camera at a white wall the meter says that it should make that white wall a middle gray color but in order to do this it would has to underexpose the image. Vice versa if you point a camera at a black wall the meter will think, this black wall should be a middle gray color and consequently give you a setting which will make that image a middle gray, hence it will overexpose the image.
The solution is to either purchase a handheld incident light meter, or purchase and learn how to use a gray card(cheap solution)

Answer 2

Most likely it will be underexposed. Your camera's metering will most likely generate a light grey wall (not white) because it will think that the predominatly white photo is a sign of overexposure.

When shooting a predominatly white subject (like snow), you need to correct "compensation" (the + or - ) to get the proper color. When you take the photo of the white wall and it comes out light grey, you need to "add" compensation by pressing "+" until you get a white wall.

If you are shooting on aperture priority, you are controling "depth of field," while shutter speed will adjust automatically. If you are shootiing on "shutter priority," you are controling speed, while the aperture will adjust automatically. Everything adjusts automatically to correct exposure.

Under automatic mode, whether "aperture priority" or "shutter priority", if your photo is under or overexposed, you only need to adjust compensation (the + or - button). If the photo is too dark, press (+) to lighten it up and take the foto again. If the photo is overexposed (too dark), press (-) to darken it up then take the photo again.

You can adjust compensation from 1/3 to 3 steps.

You have to think for the camera if its not doing its job well.

Answer 3

A lot of the answers to your question dependends on the camera and options you have. Sunny daylight at 10:00AM and Sunny daylight at 4:00PM can be different to your camera.

An "Auto White Balance" setting can usually handle the color tempiture differences. If you need an exact white balance and your camera supports {custom white balance} you might consider purchasing a grey scale card from a photo store. Shot the grey scale card just prior to shooting your image using the custom white balance setting on your carmera and it can then be used to set the "White Balance" , for your image..

Over and under exposure usually occurs if there are lighter+darker areas in your image and the camera has trouble distinguishing the differences.

Hope this helps,
Robert B.

Answer 4

Shooting a white wall on a sunny day can be tricky. You are getting more than enough light. What you need to do is bracket. That means you shoot the picture at the suggested camera setting. Then you take another shot with a bigger aperture, and then a smaller aperture. This way, you are getting more choices for the final product.

Answer 5

Your camera wants to even out exposures to a middle gray, so your white wall would most likely come out underexposed. Overexpose to correct it.

Very dark surfaces will come out too light, so you will need to overexpose them to get them dark enough.