Question about metering and AE lock...and a photo for your time

[aliciaqw]

I've been busy doing some portfolio building with family members and friends and am going nuts with this whole "metering" issue.

What is the difference between metering for a specific part of a photo and using the auto exposure lock?

Here is how I understand it, which is probably totally off. I based this from reading about the two subjects separately and have struggled finding info that talks about the relationship between the two.

When I want to meter for someones face, for example, I get close to their face and look at my meter. In theory, I want to adjust either aperture or shutter speed to get the meter at zero. This will expose the scene so that the face is properly exposed since it is what I decided is of top priority.

With AE lock, I depress whatever button I have assigned AE to and the camera will hold that exposure even if I recompose or refocus. Doing this DOES NOT allow me to adjust exposure compensation, though, right? The exposure is being decided by the camera, possibly -1 or +1, etc, because I'm not changing my settings.

Basically, I'm better off metering it on my own because that gives me more control over whether I under or overexpose a scene. The AE lock still allows the camera to decide the exposure based on your settings, correct?

As you can see-- I'm going a little batty

And to keep this interesting, here's a photo from one of my favorite places on earth-- Big Bear Lake, CA. This is the neighbor's cabin. I liked all the horizontal lines...

Thaaaaaaaaaaaaaaaank you!

 

[Vinny]

Don't know what camera you have but on a Nikon D90 the AE lock only works in one of the program modes not manual. In a program mode you are taking the exposure reading off the subject based on where you have your meter reading (center, left, right or a few points) and "locking" it as you recompose so that the camera knows what you want. Since you are in a program mode you are telling the camera to either decide on everything (auto); you want a certain shutter speed (shutter priority) or a certain aperture (aperture priority). In the lasst 2 the only thing you control is the camera setting you selected. Can you over or under expose - depends on your camera, the D90 has exposure compensation and bracketing built in and all you need is to select it.

In manual mode you are manually doing this by what you are calling metering and adjusting your camera for the "correct" reading. At this point you can also adjust for over or under exposure. When you say you get close to their face - if you are physically getting close that won't work; if you a zooming into the face then it will.

 

[mrpink]

Manual Mode = Full time exposure lock.

and what Vinny said.




p!nK