When I first started shooting with my Nikon D80, I soon developed an incredible phobia about over-exposure. Soon I was either applying -0.7EV for Matrix metering, or Spot-metering and applying -0.3EV just to make sure. Anything to avoid those dreaded blinkies! As it turns out my reward for such conservatism was noise in shadow areas (and the sky) when I would correct for the numerous under-exposed images this approach yielded.

It took the arrival of the Nikon D90 to get me to reconsider my approach. By now I was feeling a little more comfortable with ViewNX and RAW editing, and I started noticing that I could safely over-expose with the D90 by as much as 1 stop in some situations, and still recover all highlight detail in ViewNX, with the added benefit that I could draw out shadow detail with Shadow protection without piling on the noise. From experience, I developed a rule of thumb to avoid over-exposure of more than 0.7EV, and I became very good at judging this from the histogram. Anything at or under 0.7EV of over-exposure, I told myself, was fair game. I could always get back to a beautifully exposed final product with ViewNX.

The following samples try to put some evidence behind my new approach. In addition, I also wanted to know how my D80, which I still use profusely, would compare. In other words, how much can I over-expose with it and still recover highlight detail in ViewNX? To be thorough, I bracketed from the centered exposure at various -EV and +EV settings to also answer the question of how much noise creeps in when one applies +EV in ViewNX (or equivalent technique, like Levels or Curves is PP) to an under-exposed shot.

Setup and other details: The D80 samples were taken with the Sigma 10-20mm, and the D90 samples were shot with the Nikkor 10-24mm, with both lenses set at a focal length of 16mm and aperture of f/16. The Picture Control on the D90 was set to my own custom emulated control of D2XMODE1 (PORTD2XM1), and since the D80 has no native Picture Control functionality (only Picture Modes), I switched its samples to PORTD2XM1 in ViewNX. To keep things as simple as possible, the D80 was set at 1/3 stop higher shutter speed to account for the slightly brighter Sigma performance at this aperture. All other things, such as focus point and camera position through the use of a tripod, were kept as equal as possible.

Nikon D80	Nikon D90	Comments
ISO200, f/16, 1/125sec Click for full size image	ISO200, f/16, 1/100sec Click for full size image	These are the two baseline exposures, converted from ViewNX without modification. The exposure is very close to perfect, with the exception of the shadow areas, where we could stand to use some shadow protection to bring out some detail.
ISO200, f/16, 1/125sec Click for full size image	ISO200, f/16, 1/100sec Click for full size image	These are the two baseline exposures, but with +30 shadow protection applied in ViewNX. This is a matter of preference, since the more shadow protection we apply, the less contrast the image has, but I thought for this image this level of shadow protection looked good. From this point on, we'll refer to these as the "right exposure." By the way, since you'll be doing this from now on, go ahead and compare the noise in the dark brown area toward the top-right of the image... It seems Shadow protection is making one of these shots a little noisy.
ISO200, f/16, 1/200sec Click for full size image	ISO200, f/16, 1/160sec Click for full size image	Both of these are under-exposed by 0.7EV (2/3 stop), with +0.7EV and Shadow protection=30 in ViewNX to achieve the right exposure setting. Very little harm has occurred due to under-exposure, but for this and subsequent samples, go ahead and pixel-peep in the dark brown area toward the top-right third of the image and see how much noise you detect.
ISO200, f/16, 1/80sec Click for full size image	ISO200, f/16, 1/60sec Click for full size image	Now we've gone the other way, over-exposing by 0.7EV (2/3 stop), with -0.7EV and Shadow protection=30 in ViewNX to replicate the right exposure setting. Compare the noise in the dark brown area toward the top-right of the image with the previous shots. Do you see a difference? Just as importantly, compare the highlight detail along the bark of the palm's trunk to see for yourself whether highlight detail has been recovered. What do you think?
ISO200, f/16, 1/250sec Click for full size image	ISO200, f/16, 1/200sec Click for full size image	This case under-exposes by one full stop (1EV), so in ViewNX we apply +1.0EV and Shadow protection=30 to achieve the right exposure setting. Once more, take a peep at the noise in the shadow areas. What do you see?
ISO200, f/16, 1/60sec Click for full size image	ISO200, f/16, 1/50sec Click for full size image	Oh, my. Now we're living dangerously, over-exposing by 1.0EV (1 full stop). Can we get the highlights back with -1.0EV and Shadow protection=30 in ViewNX to replicate the right exposure setting? Is there a difference between the D80 and D90 shots? You be the judge.
ISO200, f/16, 1/320sec Click for full size image	ISO200, f/16, 1/250sec Click for full size image	Let's keep pushing, this time under-exposing by 1.3EV (1 1/3 stop). Do we get more noise in the shadow areas when we apply +1.3EV and Shadow protection=30 in ViewNX?
ISO200, f/16, 1/50sec Click for full size image	ISO200, f/16, 1/40sec Click for full size image	Over-exposure in these samples is +1.3EV, so we do our ViewNX trick again: -1.3EV exposure compensation and Shadow protection=30. How does the noise in the shadow areas compare, and how are the highlights doing now?
ISO200, f/16, 1/400sec Click for full size image	ISO200, f/16, 1/320sec Click for full size image	Let's push one more time, under-exposing by 1.7EV (1 2/3 stop). Check out the noise in the shadow areas when we apply +1.7EV and Shadow protection=30 in ViewNX.
ISO200, f/16, 1/40sec Click for full size image	ISO200, f/16, 1/30sec Click for full size image	Finally, we really get a blown exposure. And I mean really blown by +1.7EV, none of that sizzy Matrix metering 0.7EV over-exposure, but the real deal, the stuff weeping and gnashing of teeth is made of, right? Well, let's just give ViewNX one more try with -1.7EV of exposure compensation and Shadow protection=30. Are the highlights perfect? Probably not. Will your scrap-booking wife know the difference, or will she arise and call you blessed?

Some points regarding over and under-exposure to keep in mind...

As we have seen in the samples above, an under-exposure strategy may leave you with too much noise in the shadow areas, especially if you brighten the image in PP. Applying a given under-exposure of, say -0.7EV across the board, will guarantee that some of your shots under-expose by far more than that. Correct for that in PP, and you will have to deal with noise.

In addition, regarding the blinkies, sometimes they belong in the shot. If there is too much range to cover or if in order to properly expose the subject under available lighting conditions calls for it, so be it: let the blinkies flash all they want. For example, in a nighttime shot with street lamps, you will have to decide whether it's okay for the lamps to glow, or whether your subject will be too dark for the shot to amount to anything. In that case, let the lights bloom and blink all they want.

Finally, over-exposure is not the end of the world! I don't need to feel like a failure because I had to dial back exposure by 0.3EV in ViewNX or apply Highlight protection of 25 and/or bring out the shadows with Shadow protection of 80. In some cases, given the dynamic range of my D80 and D90 (especially the latter), over-exposing by as much as 0.7EV and applying correction through EV compensation and/or highlight protection in ViewNX yields preferrable results.

The moral of the story seems to be, yes, do avoid too much over-exposure, but know also how much over-exposure your camera's sensor can handle given its dynamic range capabilities. The D90, and even the D80, can handle an amount of over-exposure and still capture highlight detail. Experiment with your DSLR, get comfortable with RAW and ViewNX, and you too may no longer suffer from over-exposure phobia.