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
tony@northrup.org. And also I ask that you please click like down below
and subscribe if you'd like to see more videos like this.
Thanks.