Exposure Compensation & the Histogram, 1

In my opinion, the greatest advance in our ability to make well exposed digital photographs is the histogram (or the zone system with film). Read your camera’s manual to learn all of the features offered; they will vary by camera. Understanding how to use the histogram is essential. Here are two videos –

  1. Histogram #1  – This one assumes that you know very little about a histogram & does a good job of explaining it
  2. Histogram #2 – This one covers both metering & the histogram (was included in the metering post)

Here are the two histogram options in my D300. I always use the 1st of the two in order to see information for every color channel. I pay no attention to the “picture” except to note “blinkies” – the highlights were blinking in this case. The viewfinder is where the real composition work is done. Why would you expect to see anything different afterwards in the monitor’s photo preview?

In this lesson, we’ll learn to use exposure compensation (again, check your manual) together with the histogram to achieve  the exposure that you want. The lesson will be divided into two parts – this one plus another to be posted in two days.
In the meantime take a look at these photos to get some idea of where we’re going with this. There are two sets –

  • The first five are the the two poster boards we saw in an earlier post. The middle one of the five is as the camera saw it (recall that it tries to make the average exposure middle gray).
  • Compare the 5 histograms in the 5 different renditions
  • From left to right (#1-#5) the tone was adjusted using exposure compensation (-2 stops, -1 stop, 0, +1, +2); this takes us from good black at one extreme to good white at the other
  • Histograms are 8 “stops” wide from left to right (review the previous post, Exposure Adjustments, if you don’t understand “stops”)
  • Look at the 3rd poster board image where I “divided” the histogram to illustrate the above point
  • The next 11 pictures illustrate the effect of shooting an identical scene 11 times – each time with a different exposure compensation value. No other settings were changed. From beginning to end the exposure compensation was changed from -5  to +5 in one stop increments.

In part 2 we’ll consider the implication of the results shown in these images and how we can use that information to achieve the exposure we want. The basic approach is to shoot, check the histogram, adjust the exposure compensation as needed (desired), and shoot again – and continue these same steps until you get what you want. Not hard at all (but doesn’t always apply – like moving wildlife, for example).


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