It’s Tuesday Tidbit day! This Tuesday’s tidbit of information is about using your camera’s histogram…something not enough photographers do, imo.
Histo-what?
The use of the histogram is certainly not unique to photography–it’s used widely in the field of statistics. In the most general terms, a histogram is a graph of bars, with the bars representing various frequencies of a piece of data. In photography terms, those “bars” represent how many pixels (in other words, how much of your image) are at various levels between full black and full white. Full black is on the left, full white is on the right. In other words, the histogram tells you how much of your image is exposed on the dark side, how much of it is exposed on the light side. More bars on the left means a darker image, more bars on the right means a lighter image.
When you take an image with your SLR camera (if you need a reminder on what an SLR camera is, read this post), take a look at the LCD screen on the back: it should show a black and white mountain-y (yes, that’s the technical term) looking graph somewhere on the screen. If not, scroll through your viewing options and you should come across it eventually. If you still can’t find it, drop me an email, I’ll help you through it. You will also see the histogram if you edit in Lightroom or Photoshop, too.
Let’s get practical: an example
Let’s take a look at an example of an image I took at a recent wedding to see the correlation between the histogram and the actual image. I’ve circled the area on the histogram that corresponds with the area on the image itself. The darkest part of the image (the womens’ hair and their dresses) are shown on the histogram as the large peak on the left. The brightest spot in the image, the burning birthday candles, shows up as a very tall peak on the very right hand side of the image. In this case, the highlights (the candles) have been blown out, meaning we’ve lost all detail in that area; that’s why you see the peak extend up rapidly at the end and not come down before the end of the graph. There’s also slight clipping of the black areas, meaning some detail has been lost in the darkest part of the image. Some photographers will say that’s a cardinal sin–me, I don’t mind a little clipping if it makes a more contrasty, dynamic image. Anyhoo, take a look:
Yes, it’s enough to simply look at the photo to gauge your exposure, but I can’t tell you how many times I’ve looked at that little LCD screen on the back of my camera, the exposure looked fine, and then I get the image onto my computer screen and realize that important parts of the image have blown highlights or shadows. No, you don’t need to live and die by your histogram results…but I like to think of it as another tool in my tool belt that will help me get the perfect image, for when it really counts. As Ken Rockwell says, “Use them as guides, not Gods.”
Happy shooting from Vantage!
