Hi there!
My name is Franco and I'm a Photographer-by-passion
I'm here to share my photography skill with you: Easy, Simple and right to the point.
What is an Histogram?
Histogram is photographer-best-friend. there are no other words to define it.
Is a simple grafic where on the orizontal-axis we have colors from black to white, and on the vertical axis you can understand how many pixel of that tone you have.
Let's take a look at it:
Let's explain:
Black: nothing to see, pure black without detail Shadows: dark part of the picture where you can see detail (like a black dress) Midtone: just like the name suggest, everything in the middle: like blue sky, green grass, skin Highlights: all colors close to white where you can see detail (like a bride dress, white clouds) White: nothing to see: pure white without detail
Ok theorically we've understood what an histogram is, but tell me: how it have to be for understand you've a perfectly exposed photo?
The only answer to this question is one and one only: I dont know!
It sounds weired, but what I've just said is absolutely correct. Because there is no a "perfect histogram", but there is a "perfect histogram for THAT photo"
Always theorically we can say that an histogram like the one we've see before is perfect: correctly balanced from shadows to highlights, without black underexposed or white without detail.
Let's see a picture with an istogram very similar:
Histogram is almost perfect
Let's see another image:
wo wo wo, we've some black without detail here. this photo is underexposed?
Another one:
Here we've a lot of highlights an not so many shadows, it means that this photo in overexposed?
And the last one:
Hey! I can clearly see that we've got some white without detail, this foto IS overexposed!
Well... everything i wrote after every image is wrong but the first one.
lets see why.
first image: perfectly balance between shadows and highlights, no black or white without detail.
second image:
this photo is perfectly exposed. there are a lot of blacks without detail and a lot of shadows. BUT. whites are ok, i used an external flash for my friends, and i was looking exactly that mood
third image:
there are not so many pixels in shadows, but as you can see this image is almost white, and I can clearly see that I don't have white without detail, so another time our photo is exposed correctly.
fourth image:
as we can see there are some whites without detail, but in this case those whites are in the sky, subjects are perfectly exposed, so another photo ok
At this point, what we have learn?
we understood how an histogram work, and for every picture we've to understand if the esposure is ok. For example, we shoot one portrait and the blue sky is the background like this one:
Looking at the histogram the photo is a little bit over exposed BUT... if I choose to have the sky exposed correctly my subject will be absolutely under exposed. So I've decided of keep the sky in the hightone to have this mother with her son exposed correctly ;)
One last example:
For sure this photo is under exposed, and I've almost all the pixels in black and shadows, because I've shoose to keep the background exposed correctly to see clearly the silouette of that girl.
My suggestion is:
Shoot, shoot and shoot again: try to do things, look what you did and learn by yourself how to read your histogram: take a photo of something and without download on your computer try to understand if is ok, under or over exposed.
Ok Franco, I understood what I've to do if my histogram doesn't match my idea of the photo I'm shooting. But what I've to do to choose right exposure and if I've to compensate what I've to do?
In the next Tip, we'll talk right about that!
Franco