why medium?

[grooski]

Why is it when you expose film that you get medium tone? Why can't it just be the tone what you see? It would be nice if i had a lot of answers. Thanks. :shock:

 

[ksmattfish]

You only get a medium tone if you expose and develop to get a medium tone.

The meter tells you how to get a middle tone, but you, the photographer, should be running the camera, not the meter.

If I meter off a gray cat, and use the recommended settings, I will get a gray cat. If I over expose from the recommended settings, the cat will get lighter (how much depends on how much I over expose). If I underexpose, the cat will get darker.

If I use the meter recommendation when photographing a black cat, the cat will turn out gray in the photo. As a photographer I need to understand that to get a photo of a black cat, I should under expose by 2 stops from what the meter tells me to shoot at.

If I were shooting a white cat, I would overexpose 2 stops. Once again the meter tells me how to get a gray cat, so I need to over expose to lighten the cat.

If I were shooting a white cat, but wanted it to look like a black cat I would underexpose 4 stops.

Beyond exposure I can also adjust the tonal range of an image somewhat when I develop the film, and when it is printed.

Another way is to use a gray card. A gray card is a piece of cardboard or plastic that is middle gray. If I meter off the gray card under the same lighting as my subject (for instance have the subject hold the card while I take the reading), and use the recommended exposure, then the tones of my subject should fall into place.

Edit: If I don't have a gray card, I happen to know (because I measured and compared to a gray card) that my palm is approx 1 stop brighter than middle gray. I also know that in my neck of the woods green grass lawns are approx middle gray in tone.

 

[Big Mike]

Think about it like this...

A camera is just a mechanical device to expose light to film. The aperture can be one of about 10 different sizes and the shutter can stay open for a variable length of time.

So how do we know what combination of aperture and shutter speed to use? We use a light meter to measure the light and set the camera accordingly.

When cameras were made with automatic exposure...they had to be set to expose for a specific value. It could have been anything but it made sense to set it to 18%, or medium tone. This works well for the snap shooter who wants to leave the camera in auto and just take pictures. For those of us who know that the camera's meter will give us a reading for middle tone, we can adjust the setting to get what we want.

Did that make any sense?

 

[grooski]

ya it did, but it's just more on why, if you expose it corretly does it become medium tone?

 

[Big Mike]

Exposed correctly is a matter of preference.

The camera's meter will give a reading to make the subject medium whether the subject is medium or not. You, as the photographer, must make the decision to compensate for shadow, for highlight or to make a compromise between the two.