0

Exposure Compensation and Spot Metering: Fixing Underexposed and Overexposed Pictures


Hi, I’m Tony Northrop and I’m in the snow
today because I had a Stunning Digital Photography reader ask me to provide
more information about camera metering, metering modes and exposure compensation. So I waited for a fresh snow here in
Connecticut because snow is one of the perfect
examples for a situation that requires you to change your camera’s default
metering. So, to explain this a little more i’ll take a couple of sample shots
of Chelsea. now and take a look at that No, take a look at that picture and especially the histogram, because it’s really important that you review the histogram anytime that there
is an exposure challenge, like a bright environment or a dark environment. This
histogram is almost entirely in the left half of the frame, and that’s no good at
all, that means our picture is underexposed. Now, you can’t just trust
your eye here because a million times i’ve looked at the preview of an image on my
camera when I’m not shooting and thought it was ok, then I get back to my computer
and see the histogram and realize it’s wildly underexposed. You can’t trust your
camera’s LCD, you always need to look at the histogram. So when you see a histogram like this
that doesn’t touch the right side, that means the photo’s under exposed. And as a
rule of thumb, when you’re in a bright environment like this, you need to add at
least a stop of exposure compensation but when it’s mostly snowy like this, you need to
add a couple of stops of exposure compensation. So I will add two stops of
exposure compensation and shoot again. That turned out much better. Now, that’s really all you need to understand
about metering and exposure compensation. Take a shot, look at the histogram. If it
doesn’t touch the right side of the frame then you need to add one or two or
three stops of exposure compensation. Shoot again and if the histogram is perfect then
you’re good. Back in the olden days when we shot film,
you didn’t get a chance to immediately review it and then reshoot. And as a
result cameras developed these really complex and flexible metering systems
and they’re still in our modern cameras. And in fact, the camera manufacturers
often use them to advertise advantages of their models vs competing models but
I don’t think they’re that important. Because nowadays I think the easiest
thing to do is just to take a shot and make an adjustment based on what you see. However, I do want to give you an overview
of your camera’s different metering modes. Now the one that your camera is probably
set up with by default is- they have different names. Some companies call them evaluative
metering, some art zone metering but they look at the entire frame and
intelligently decide what the exposure should be. So they’ll look at your
foreground subject and the background subject and try to guess. That’s what my
camera was set up with when it managed to underexpose that shot by a couple of
stops, so it doesn’t work perfectly. The way your
cameras metering system works is it tries to figure out what’s important in
the frame and then make that a middle gray, right in the middle of the
histogram. Now, in the olden days you’d even hold up a grey card and meter off
of that grey card and you’d feel pretty good about it. But it doesn’t work well
in an environment like this where everything is white. You see the snow, I don’t want it to
appear gray, but that’s the way it appeared in the first shot. I want the snow to appear white because
that’s how it looks to my eye. It should be almost all the way to the right side of
the histogram and that’s why my camera mis-exposed it and that’s why I had to
adjust it with exposure compensation. Now, another way to fix that besides
using exposure compensation is to use spot metering. Now, many cameras have different types of
spot metering. They might call it center weighted or partial metering. True
spot metering takes a very small part of the frame and meters off of just that.
Sometimes it’s linked to the focusing point, but usually it’s right in the middle of
the frame. So I’ll take a shot with spot metering on and no exposure compensation
and we can see how that works. Now you can see in that shot I metered
off of Chelsea’s face which, because of her darker skin tone is about what middle
gray should be. The background is brighter, so the camera actually adjusted
the exposure so where I put the spot metering sensor would be in the middle
of the histogram. The snow, being brighter, ended up on the right side of the
histogram for a perfect exposure. I don’t really like spot metering though.
First, it works differently in different cameras, so you really have to learn how
your camera works and experiment with it to get it to work right. Second, it meters off of a very small
part of the picture and with moving subjects, where this might be
particularly useful, it’s really easy to move to a dark or
light part of the subject. So for example, I try spot metering with flying
birds. What happens is, if I get the spot
exactly on the flying bird the exposure will be perfect. But the next frame maybe
the bird moves up or down a little bit or my camera’s not perfectly centered on
it, and the meters off the bright sky and the exposure drops way down because it
tries to make the sky gray. Maybe then meters off of a dark part of
the bird and it moves the exposure way up. Now I’d like to illustrate what
happens when you have a dark background. So let’s take Chelsea and move her in front
of some dark trees and we’ll repeat this experiment. This isn’t the most scenic spot for a
portrait but it will serve for an example here because it’s got a nice
dark backdrop. Now, i’m going to retake this photo but i
want to remind you to please read through chapters three and four in
Stunning Digital Photography because it has a ton of detailed information about
exposure and the exposure square which includes aperture and shutter speed and
all the camera settings that you need to understand to be able to work it
properly. So my camera’s set to evaluative metering and no exposure compensation.
I’ll take another sample shot. If you look at that, Chelsea’s face is now overexposed. And the reason for that is
the camera included the dark background in the metering, and it tried to bring
the background up to middle gray. Chelsea’s face is now brighter than the
background, meaning it pushed that exposure up beyond the right side of the
histogram causing it to be blown out. Now, it’s really easy to detect if you look
at the preview and you enable blinkies, which i described in the book. So, because
I can see it blinking, I immediately knew that I needed to just adjust the
exposure compensation down. I can also look at the histogram and if
I see the histogram climbing up the right side there, that means I need to dial down 1 or 2 stops
of exposure compensation. sSo I’ll just dial in a couple of stops and retake
that picture. That was enough to fix it. So remember, when you have a bright
background you need more light. If you have a dark background, dial your
exposure compensation down. It works exactly the opposite of the way
you would think it would, but you don’t need to memorize anything. All you need
to remember is look at your picture after you take it, and examine the
histogram. Then adjust the exposure compensation. Even if you get it backwards, you’ll figure
it out after you take your next test shot. Thanks so much for watching my video, I
hope you’ll check out my book Stunning Digital Photography which you can get at
Amazon or at sdp.io/store or any other place that
sells ebooks. Now, this is the top rated photography
book in the world so it’s worth checking out. The reviews at amazon say it all
I think. If you have any questionss please don’t hesitate to contact me. You can find me
at facebook at Northrup Photography, there’s a link down there in the
description, or you can send me an e-mail [email protected] And also I ask
that you please click like down below and subscribe if you’d like to see more
videos like this. Thanks.

Bernard Jenkins

Leave a Reply

Your email address will not be published. Required fields are marked *