March 28, 2019 2 Comments
The almighty Histogram, this could, in fact, be the skill you learn to move you from a hobby photographer to your friends saying “damn you could sell those shots”. Your mum probably says that already but let's be honest, she bought your finger paintings too.
So what’s the deal with this histogram thing? I'll try to keep this simple and dive deeper as we go on.
Simple version: It’s a graph that represents how many light and dark pixels are in your image.
Why this is important: By seeing this graph you instantly know if your exposure is correct because you can´t trust the image represented by the LCD screen on your camera. You can then make post-processing adjustments that look natural and free from creating weird editing effects in your image.
The histogram is the way you can determine the exposure of your image. You can use it to tell if your photos are underexposed, overexposed or if you’ve clipped any shadows or highlights. A histogram is a graphical representation of the tonal distribution in your photograph and it gives you a good idea of the range of tones from pure black (with 0% brightness) to pure white (with 100% brightness) and all of the shadows, mid-tones, and highlights in between.
The horizontal axis on your histogram shows al the brightness values possible in the photo. Pure black on the left, middle grey in the center, pure white all the way to the right. The vertical axis shows the number of pixels that have that particular brightness value. The more pixels you have at a certain brightness in your photo, the bigger the spike in the histogram you’ll have.
Now that we understand what the histogram represents, how do you we use if for our photography?
Set your camera up so when you review an image the histogram comes up, you can then see a realistic result of the image you have captured and adjust your settings for the next shot.
"Why can't I just review the image on the back of the screen?" You might be able to make a quick review by just looking at your LCD screen, but let me say, you will be played for a fool just as I have been many times. Your screen is just too small and gives a quick JPG preview of the image. In bright light the screen is hard to see, in the cold, the LCD screen does funny things, and in the dark, you think your image is brighter then it really is. Finally, you get back to edit your glorious shot to find that it is blown-out or way underexposed.
A simple rule is that a correct exposure would have a bell curve with the graph weighted in the middle and thus have a good balance between the shadows, highlights, and mid tones. However, there is no one perfect histogram for all images and if we used this rule of thumb for our winter images then all the snow (highlights) will be underexposed and look grey and drab.
A balanced histogram is weighted in the middle like a bell curve.
If you are shooting in the winter with 90% of your image being white snow, then all those white pixels are going to be added up on the right-hand side. Whilst this may not look like a correct exposure given what I said about the correct exposure graph, exposing your images with a histogram that is weighted to the right-hand side, (but not off the graph, A.K.A clipping your highlights) means all that white snow is captured as lights tones, just as it should be.
By shooting to the right, you are in fact telling the camera to overexpose your shot but by doing so, your white snow will be white and your winter images will POP!
If shooting in Auto mode, add +1 or +2 to your compensation dial to achieve a histogram-weighted to the right.
The histogram in this wintry image is weighted to the right.
This is the general rule for landscape photography meaning your histogram is weighted to the left (more dark pixels) and the highlights that are captured have tonal information instead of a blank white dot. This technique is used because it is easier to lift your shadows in post then to darken your highlights especially your highlights not blown out (pure white).
This second tip is in pure contradiction to the first tip and is really a guide for summer images. Of course, winter doesn't always mean there is snow everywhere so keep this tip in the back pocket for the not so snowy winter days.
Have you heard this before? I have just mentioned it a couple of times and you will often hear people talk about clipping your highlights or your shadows?
This is when the information represented on the histogram goes off the graph. There is no information on the pixel in either your highlights or your shadows, it is just pure white or black.
Of course, there are times when this is ok, but we won´t worry about that now, it’s more important to understand what that means. (to put you at ease an obvious example of when clipping is ok is with a silhouette, the dark shape will clip your shadows.)
For the most part, you should try to avoid clipping your highlights or shadows as there is then absolutely no chance of recovering the detail when editing your images. What does this look like? Your highlights are plain white, as you adjust your image all that happens is those pixels become a darker shade, from white to grey without any color. I will explain this more when we look at the Histogram for post-processing.
Glad you asked. This is definitely going to happen and the scope at which your camera can capture both highlights and shadows is called the Dynamic range.. we are diving deep now.
Essentially you have a very bright light and a dark dark shadow in the same shot and you are unable to gather all the information from both sides of the spectrum.
Think “Portrait in a cave looking out to the sunset”. Your face is in a dark place and shaded, whilst the background is extremely bright and well lit, you just can't take a shot where both the elements (your face and the sunset) are properly exposed. This is where advanced techniques like using filters or exposure blending come out to play. We won´t go down that rabbit hole but I hope the idea is understood.
This is why understanding your histogram is important and even more so during winter when light conditions (photography is all about the light) are tough and hard to meter. If you are seeing that things are clipping you may need to move your subject into the light or give priority to either your highlights or shadows.
Located in the top right panel in the develop module, the histogram is the very first thing you’ll come across as you’re processing an image. The Histogram in Lightroom aims to better illustrate the relationship between sliders and the tones in your photos. The histogram will reveal if the original photo was under or overexposed and as you adjust your exposure, it will also reveal if you’ve clipped any highlights or shadows.
To check for clipping, click the triangular icons in the top left and right of the histogram (or use the keyboard shortcut “J”) If the triangles are colored dark grey, this means there is no clipping of the highlights or shadows.
No clipping is present
When the shadows, whites and black sliders are changed, clipping in the shadows appears.
If you adjust your white or black sliders, you’ll see the triangles change to a light grey and the clipping will start to appear in blue (for shadows) and red (for highlights). Seeing a lot of blue or red in the clipping means you’re losing detail in those shadows or highlights.
As I move the exposure up past +1.5, you can see the clipping appear, signifying a loss of detail in that part of the photo.
As I move the exposure down past -2.5, the blue starts to appear signifying a loss of detail in the shadows.
If the histogram is heavily weighted towards the left, it signifies the image is underexposed (unless of course, you were purposely shooting darker images.)
If you don't want to use the sliders to make adjustments, you can also make adjustments right on the histogram. A simple click in the section you want to alter and drag to the left or right. Clicking and dragging in the sections outlined below will change the corresponding sliders.
Using your histogram with Winter photography is a game changer, Shoot to the right and your winter photos will pop and hold that winter crispness.
An easy way to keep shooting to the right is by adding +1 or +2 to your exposure compensation dial. If you shoot in a priority setting then this tells your camera to overexpose the shot (shoot to the right) and if you shoot manually, your camera will meter your shot the same way, nice and bright.
For post-processing, the histogram is extremely helpful in letting you know if you have edited that touch too far, so make sure it is always visible.
While it's true there's no perfect histogram for every photo, there are guides and understanding how this magical graph works in relation to your what you have captured will help fast track you to better winter images with perfectly white snow.
Be sure to share your winter images by tagging #builtforwinter and as always, if you have any questions, leave a comment below. Happy shooting!
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