selkovjr
Adjusting the exposure level
Previous: Decoding the raw files
The goal at this stage is to stretch the histogram as wide as possible across the the available dynamic range of the output image. For this picture, the value of 1.2 does it; I simply go ahead and type it into the Exposure Value box. Alternatively, I could slide the slider, but I am used enough to the EV numbers that I can just dial the approximate number right away, and then adjust it with a couple clicks on either side of the slider, if it is not right — that saves me mouse travel.
If you don't know right away how much to adjust the exposure value, move the slider to the right until the image becomes overxposed (the second line from the bottom, now showing 0.0% will show a non-zero number), and the bright spots on the image will start looking awful. Then step back until the number becomes zero again. Then, look at the histogram and if it has a sharp spike at the bright edge, step back some more. Too many pixels aggregating at the bright edge, even though not technically overexposed, will make the picture look bland. Keep moving away from the threshold of overexposure until the histogram tapers off smoothly, as the blue histogram does in the above image. That is not always possible, but a properly exposed image should allow you to do shape the histogram this way.
Did I tell you to enable the histogram view while taking the pictures? This is the reason why. This is how the histogram should have looked in the camera while the picture was taken, but I was almost facing the sun when I took it and could not see it too well. Another bit of advice following from this:
- have a piece of dark fabric to throw over your head when the ambient light is too bright
And something I came to take for granted:
- use the lens hood
This picture came out reasonably well in part because the camera had the lens hood on it. Without it, shooting at such a close angle to the sun would produce unsightly reflexes. I never take the hood off, by the way. It improves contrast in any light (if only a bit), and it protects the lens from bumping into things; I have never had to wipe my fingerprints from this lens because the hood eliminates the possibility of accidental contact.
The procedure for normalising the highlights I just described is likely to affect the darks. So, once satisfied with the highlights (in this case, in the sky), check the bottom of the range by pushing the Indicate button in the underexposed values row. What do we see here? It's looking pretty good. The only severely underexposed area is the shadow under the car, which is not important. That spot can be as dark as a black hole, for all I care. There is also an insignificant number of underexposed values elsewhere in the image — 0.7% including the shadow under the car; that's close to nothing, so whe can move on to the next stage.
The image still does not look right. The highlights in the sky are fine, but the mountain looks as if it was painted in ink. The darks are darker than they should be. That is because the standard gamma curve, which would work well with a picture shot in the daylight, is too shallow to reproduce the sunset lighting correctly.
Adjusting the exposure level
Previous: Decoding the raw files
The goal at this stage is to stretch the histogram as wide as possible across the the available dynamic range of the output image. For this picture, the value of 1.2 does it; I simply go ahead and type it into the Exposure Value box. Alternatively, I could slide the slider, but I am used enough to the EV numbers that I can just dial the approximate number right away, and then adjust it with a couple clicks on either side of the slider, if it is not right — that saves me mouse travel.
If you don't know right away how much to adjust the exposure value, move the slider to the right until the image becomes overxposed (the second line from the bottom, now showing 0.0% will show a non-zero number), and the bright spots on the image will start looking awful. Then step back until the number becomes zero again. Then, look at the histogram and if it has a sharp spike at the bright edge, step back some more. Too many pixels aggregating at the bright edge, even though not technically overexposed, will make the picture look bland. Keep moving away from the threshold of overexposure until the histogram tapers off smoothly, as the blue histogram does in the above image. That is not always possible, but a properly exposed image should allow you to do shape the histogram this way.
Did I tell you to enable the histogram view while taking the pictures? This is the reason why. This is how the histogram should have looked in the camera while the picture was taken, but I was almost facing the sun when I took it and could not see it too well. Another bit of advice following from this:
- have a piece of dark fabric to throw over your head when the ambient light is too bright
And something I came to take for granted:
- use the lens hood
This picture came out reasonably well in part because the camera had the lens hood on it. Without it, shooting at such a close angle to the sun would produce unsightly reflexes. I never take the hood off, by the way. It improves contrast in any light (if only a bit), and it protects the lens from bumping into things; I have never had to wipe my fingerprints from this lens because the hood eliminates the possibility of accidental contact.
The procedure for normalising the highlights I just described is likely to affect the darks. So, once satisfied with the highlights (in this case, in the sky), check the bottom of the range by pushing the Indicate button in the underexposed values row. What do we see here? It's looking pretty good. The only severely underexposed area is the shadow under the car, which is not important. That spot can be as dark as a black hole, for all I care. There is also an insignificant number of underexposed values elsewhere in the image — 0.7% including the shadow under the car; that's close to nothing, so whe can move on to the next stage.
The image still does not look right. The highlights in the sky are fine, but the mountain looks as if it was painted in ink. The darks are darker than they should be. That is because the standard gamma curve, which would work well with a picture shot in the daylight, is too shallow to reproduce the sunset lighting correctly.