today I'll show you what a histogram is and I want to see whether it's still
relevant to get a good photograph in 2019 the histogram is basically a graph
showing the distribution of the luminance of the pixels in your
composition from pure black to pure white digital cameras have had them for
a long time and when you open up your image in any kind of decent editing
software you will get a histogram of your image if you have that setting
turned on so they must be important but how do they work how do you read them
and how can you use them in your day-to-day photography to make your life
easier first of all a histogram is a graph on your vertical axis is the
number of pixels and along the horizontal axis is the luminance range
from pure black to pure white this normally has about 255 different shades
some have more some have less depending on the quality of the histogram the Sony
cameras don't have great histogram displays but they're still useful and
you can still use them the best way to understand a histogram is to look at a
basic black and white image if you look at this image there are five shades
going from black to white on the histogram there are five lines showing
how many pixels are in the image as there are only five shades there are
only five zones filled in the histogram if you look at this image I have put ten
shades from black to white on the corresponding histogram there are ten
zones filled in this third image there is a gradient from black to white so it
contains all of the range from black to white you can now see on the histogram
this range of tonality x' and the number of pixels in each zone and this is
basically how a histogram works it shows you the number of pixels in each of
those zones from pure black to pure white so I've just set my camera up on
the tripod looking out of my window so it can show you what I mean by the
histogram if we look at this shot because here I've got this really dark
patch here and this is the window frame and that relates to this big spike on
the left and side the brighter bits in the
distance where you can see the sky in these three sections there that's this
little bump towards the right of the histogram this medium-sized bump in the
middle relates to the buildings now if i zoom in getting rid of this window frame
watch how the histogram changes so you can see that big spike on the left-hand
side is now disappeared we've got more of a spike here so this spike on the
left-hand side now relates to the buildings and the spike on the
right-hand side relates to the bright parts in the sky as you can see as I
change my composition the histogram changes as I bring in that window frame
you can see that spike peak on the left-hand side and as I come away from
that that spike disappears now if I change my exposure compensation so I'm
going to bring it to one stop maybe one and a half stops over you can see the
sky is completely overexposed if you look at the histogram it's bunched up to
the left-hand side we still have a little bit of a lump in the middle and
that relates to the front of these buildings so if your histogram looks
like this and you don't have the Zebras on warning you of this then you'll have
to bring your exposure down if you're in aperture priority you can use your
exposure compensation dial to do this if you're in manual mode you'll have to
adjust either ISO aperture or your shutter bringing down the exposure so
you don't clip the highlights so I've dropped my exposure compensation dial to
two stops under what the camera thinks the exposure should be you can see now
that the buildings are really dark they relate to this spike on the left hand
side so we've still got these brighter parts in the sky but there are a lot
less brighter than they were with a correct exposure so you can see these
parts of the sky relate to this little spike in the middle so once again I'll
take it to one stop under and you can see as I bring the exposure up the
histogram is slowly moving to the right if I bring it up to zero on the meter
you can see it's kind of evening off but because there's some dark parts where
these buildings are the bright parts where the sky is it's
almost like a double spiked histogram with the color image some more advanced
programs might break up the different colors so a look at red green and blue
separately it also does it on this preview screen on the back of the Sony
cameras this is just showing the distribution of pixels per color channel
in your image now hopefully that all makes sense basically when you look at
your histogram if your shot is overexposed it'll tend to be skewed to
the right if it's underexposed it'll be skewed to the left all you need
to do is make sure it's not clipped so it's not really bunched up to one side
or the other otherwise you'll start to lose detail in
your highlights when it's bunched to the right and your shadows when it's bunched
to the left now you know how it works there are quite a few bits of
information you can gather from your histogram when you have it up on your
display when you have a well balanced image the histogram will look like this
this means the luminance levels are well within the capabilities of your camera
and you will have detailed throughout your image when the histogram is bunched
to the right chances are you'll be clipping your highlights this means
you'll be losing details in the brightest part of your image if this is
the case you will need to bring down your exposure to make sure you keep all
of that detail in the highlights if your histogram is bunched to the left-hand
side chances are you'll be starting to lose
detail in your shadows if you increase your exposure to bring it away from the
left-hand side you'll tend to avoid this problem if your histogram is touching
both sides like this chances are you'll be losing detail in the highlights and
the shadows this normally means that dynamic range is too big for your camera
so unless you're going for a silhouette shot or a contrast II image you'll need
to do something to get a better photograph either by framing up a
different shot where the dynamic range is smaller or by bracketing your shots
if you don't know what bracketing is but want to learn more click on the eye in
the corner this will take you to another of my
videos now if you go on that information alone and always use your histogram
you'll try and get a nice smooth curve in the middle of the histogram but this
doesn't always work and this doesn't always produce a really good image so
there are exceptions to this rule and this is where it comes down to personal
taste one image might look good to one person but another person might not like
it at all so I've loaded into lightroom some example images these first images
are of a snowscape on the south island in new zealand the images are very
bright but I've tried not to push the histogram all the way to the right hand
side so with this one with the Sun you can see that's this little tag in the
corner but everything else is exposed okay that means there's a bit of a gap
and then we have all of our colors here the histogram is skewed to the right but
it's still a good exposure with this next one it was a little bit more stormy
and the Sun wasn't out but you can see I'll push the image all the way to the
right but just before it's overexposed then this one of Mount Cook it's a
slightly darker image but you can see again the histogram is pushed over to
the right this next one is a hot-air balloon
over a mountain again there's lots of whites in the image and you can see this
on the histogram it's all shoved over to the right with this next image it's
almost on the opposite end of the scale the histogram really is bunched over to
the left but I still really like the image the sunlight was catching this
staircase up the side of the volcano and it really makes it stand out all the
shadows are disappearing off into the distance but it's quite a striking image
I took this next shot from a plane window again it's quite striking and the
wing is really bright as are the clouds but then the sky is really dark as is
the sea and you can see this on the histogram
I think this spike here is probably the wing and then this big lump here is the
sky and the sea now this silhouette at sunrise has lots of darks in the image
and you can see that here on the histogram and where the Sun is just
creeping into the image that's this little tag here
I have this image of the corner of a Buddhist temple in Singapore I've
purposely darkened down the sky and I've upped the contrast on it the only things
that really stand out are these parts of the roofs the rest is really dark we can
see that on the histogram I think it's still quite a striking image it really
does stand out but if you've just looked at the histogram alone you'd want to
raise the exposure next I'm gonna have a look at a few contrasting images as you
can see with this one the Sun was just behind this mountain it was bouncing off
the clouds up above and you can see all of the lights were still on in the city
this bright area in the middle of the shot is this peak here on the histogram
and then the darker areas down here and up here in the clouds well that's this
part of the histogram again the histogram isn't that kind of bell curved
pattern but I think the image really stands out with this image we've got
more of a distribution of luminance from black to white you can see on the
histogram there's a few spikes but it's much more evenly distributed and then
this last image there's a really dark part down here which equates to the
left-hand side but then it goes right through the range up to this bright part
of the cloud which is probably this spike here that might even be this part
here but there is a range from pure black to pure white and we can see that
on the histogram as you can see from these examples no one pattern on your
histogram will cover all photographs some will skew the histogram one way and
some will skew the histogram the other way it all comes down to personal taste
what you like and what you're looking for in your images but the more you use
your histogram the more you'll understand it and the more you'll be
able to use it to better your photography process another tool which
is very similar to the histogram is the zebra function if you shoot with a
mirrorless camera and want to learn more about zebras click on the I in the
corner this will take you to another of my videos and that's about it the
histogram is an aging tool and it's been in digital cameras for a really long
time but if you know how it works you can use it to get really great
exposures as always if you like what you see give me a thumbs up if you didn't
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