selmslie Loc: Fernandina Beach, FL, USA

That video is about post processing, nothing to do with looking at the camera's histogram "when composing an image".

Not many cameras show you a histogram before the image is captured.

wds0410 Loc: Nunya

Spot on! Well done.

drobvit Loc: Southern NV

As always, an excellent, easy to understand tutorial from BackcountryGallery! Thanks Steve.

burkphoto Loc: High Point, NC

Histogram is a frequency distribution plot of the tones in the JPEG preview image (part of every raw file and JPEG recorded by your camera). The default histogram is just luminosity (brightness). Separate red, green, and blue histograms are also displayed on some cameras.

On the left, is black (0 red, 0 blue, 0 green). On the right, is white (255 red, 255 blue, 255 green). At dead center is neutral gray (127, 127, 127). When viewing a color histogram, the range is black to full red, or full green, or full blue.

You have to use it as a guide, not an absolute.

Some folks tell you to "fill the histogram as far to the right as possible without touching the right edge of the graph." That can be important in many instances, but if the subject is a black cat in a coal bin (a very 'low key' scene), it's just wrong. It would make a milky, grayish mess. Conversely, if the subject is a Caucasian blonde bride in a white dress, standing against a painted white brick wall (a very 'high key' scene), a full histogram would make a dull, muddled mess.

One thing you CAN use the histogram to do is to evaluate EXPOSURE in reference to a target. If you meter a neutral gray target, and nothing but that target (i.e.; fill the frame with it), in the light falling on your intended subject(s), the exposure of that target will be correct (for a JPEG) when there is a single white spike in the exact center of the histogram.

You may also use that same technique to evaluate a custom (manual, or preset) white balance. In "color" histogram mode, the three colors will all be on top of each other, making the spike from the gray reference target very narrow.

When using raw capture with EBTR ("expose beyond the right" of the histogram technique), the histogram is still a guide, but you have to know through testing how much latitude your camera has for overexposure in various circumstances. With EBTR, you can eke out a stop or more of dynamic range for brilliant, mid-day daylight scenes. This reduces apparent noise and adds shadow detail.

In short, the histogram is just a guide to the relative distribution of processed tones in your JPEGs. It is subject to interpretation, which is subject to personal taste.

rmalarz Loc: Tempe, Arizona

Bill, A very good explanation. However, there is one slight, but important revision to be made.

"When using raw capture with EBTR ("expose beyond the right" of the histogram technique), the histogram is still a guide, but you have to know through testing how much latitude your camera has for overexposure in various circumstances. With EBTR, you can eke out a stop or more of dynamic range for brilliant, mid-day daylight scenes. This reduces apparent noise and adds shadow detail."

The use of overexposure in your above statement. Technically, it should be ...has for additional exposure... Once something is overexposed, information is lost and irretrievable.

Additionally, your advice that ...through testing... can't be emphasized enough. That is the key to ETTR/EBTR techniques. But, something most are adverse to doing.
--Bob

BobHartung Loc: Bettendorf, IA

Remember this: The histogram is nothing more than an approximation of the number of pixels at various luminosity levels in an image and it is derived from an 8-bit jpeg, the preview image. As such it is only an estimate and should be used accordingly.

camerapapi Loc: Miami, Fl.

It is very difficult to add something to the already excellent explanations other members have offered and in addition you have Mr. Perry's video which is very useful indeed. I will say now what others have already discussed and it is that there are many histograms that looking great they do not offer the correct information. I have seen many "perfect" histograms and ALL of them came short in the middle tonalities. My experience with my Nikon cameras has been that I must stay short of the right border for good highlights. If I get closer to the border highlights will be overexposed. I am usually not as concerned of the shadow areas except when metering for them. I am sure you know that digital allows to open the shadows although we have to watch for noise.

As other have said, histograms are only a guide.

selmslie Loc: Fernandina Beach, FL, USA

You have to wonder why that would ever be necessary.

A bright mid-day scene can easily be captured at or near base ISO without any danger of noise in the shadows. At low ISO the camera's DR is wide and noise is seldom an issue.

Besides, if some of your shadows are not actually black, your image is going to look gray and flat.

EBTR is more useful where the light is not bright and you are forced to raise the ISO thereby reducing the camera's DR.

burkphoto Loc: High Point, NC

We can make a further distinction that exposing beyond the right is not overexposure for the raw file, but the processed JPEG preview image will appear overexposed. EBTR technique is for recording raw files. Post-processing them is required to pull the tones within a range that works on a monitor or print. It's a form of dynamic range compression.

EBTR plus post-processing is a bit like the old trick of overexposing B&W negative films (rating them at a lower exposure index, or false ISO), then developing them in a gentle developer that maximizes shadow density while avoiding building excess highlight density.

rmalarz Loc: Tempe, Arizona

Exactly!!!
--Bob

rmalarz Loc: Tempe, Arizona

Wonder no more. The technique provides a method to place the brightest portions of a scene in an appropriate Zone.
--Bob

selmslie Loc: Fernandina Beach, FL, USA

I understand the technique.

But where’s the noise in broad daylight?

williejoha

Paul, you hit the nail right on the head. Seldom do I look at the Histogram. Being able to reduce noise and recover blinkies is a lot more important to me.
WJH

BobHartung Loc: Bettendorf, IA

Aye and it pays to know your camera. All sensors are not equal, and two different cameras with the same sensor may behave divergently due to the manufacturer's software. Again, learn what you camera does.

rmalarz Loc: Tempe, Arizona

--Bob