Emmon’s Preserve: Learning to Expose for Post!

Deep in the Green

Deep in the Green

Emmon’s Preserve, managed by the Kennebunk Land Trust, is one of my favorite places to photograph. It is also one of the most difficult. A river runs through it ūüėČ under a solid canopy of maples and pines, and depending on the weather can be anything from a trickle down over rocks and through pools to a raging torrent. The light is very tricky. Lots of shadow, from open to deep, and shafts of full sun illumination random patches of¬†vegetation, a rock here and there, and select passages in the stream…often a single curl of water around a stone. It is any exposure system’s worst nightmare. Then too, the light is green in the shadows which gives most white balance automation fits.

And it is beautiful with an almost mystical beauty.

So I go back again and again to try again and again to capture what I see and feel there…with never any more than limited success. The dynamic range, from bright foliage to deep shadows under banks…from sun on water to shade under ferns, is simply too great for any sensor to capture. It does not matter whether you are using auto exposure in your camera, or computing manual exposure using the zone system, there are simply limits to what can be done.

This shot comes from an area of the Preserve I only discovered on my last visit. I don’t know how I missed it all these years, but a side trail loops up over a small ridge and comes back down to the river above the rapids and pools I know so well. This section is quieter, but with its own beauty.

Emmon’s Preserve is a great place to learn about exposing for post.

When shooting in Emmon’s preserve, I continue to experiment with different degrees of Exposure Compensation in the camera. Too much and you get great highlights but shadows that are totally blocked up and black. Too little and you get highlights which are burnt out and pure white. And of course the light in there under the canopy is never the same twice. You have to develop a sense of what will work. And you have to keep trying.
With a camera like the Sony DSC H50 that has true live view, you can judge, or maybe learn to judge would be more accurate, the effects of your chosen Exposure Compensation…you can see pretty much what you are doing.
When shooting in Emmon’s preserve, I continue to experiment with different degrees of Exposure Compensation in the camera. Too much and you get great highlights but shadows that are totally blocked up and black. Too little and you get highlights which are burnt out and pure white. And of course the light in there under the canopy is never the same twice. You have to develop a sense of what will work. And you have to keep trying.
With a camera like the Sony DSC H50 that has true live view, you can judge, or maybe learn to judge would be more accurate, the effects of your chosen Exposure Compensation on the LCD…you can see pretty much what you are doing.
Still, the proof of the pudding doesn’t come until you try to process the image back on the computer.¬†Even if you use the camera’s exposure compensation, or manually compute a compromise exposure, an image like this requires post-processing.

I use Lightroom, and it has both Recovery and Fill Light tools. Both are tone mapping tools, in that they change the relative exposure values (tones) for a selected range of tones, and only that range. Recovery selectively reduces the intensity of highlights within the image. It is a simple slider and you can watch its effect in real time as you move it. Fill Light is exactly the opposite. As you might expect from the name, it increases the exposure level of only the shadows. Again, it does it in real time, as you move a slider.

Tone mapping is a powerful tool, bull all tone mapping tools, and Fill Light in particular, require restraint. Over use leads to strange and easily recognized halo effects at sharp contrast boundaries, especially where land meets sky. When you see a little whitish line running along the tops of mountains in some HDR  images or outlining tree branches caught against the sky, it is the result of aggressive tone mapping (high dynamic range images are generally tone mapped to fit the expanded contrast scale from multiple exposures into the limited scale of the monitor or printing device).

In this image, heavy Recovery was needed to bring out any detail in the brighter areas back among the trees, and Fill Light was needed to open the shadows.

I have mentioned before that post-processing in situations like this is not used to save an incorrectly exposed image. In the field you expose the image knowing what you can and will do to it in Lightroom (or whatever software you use for post-processing). You expose it differently than you might if image editing software were not available. I used -.7 EV exposure compensation in the camera in the field to tame the highlights back among the trees.  -.7EV is not enough to bring out all the detail in the highlights, and yet already it makes the shadows too dark, obscuring detail there. -.7EV is, however, the correct place to begin expanding the dynamic range with the tools available in Lightroom. All but the brightest highlights can be brought back in range by Recovery, and the Fill Light tool does a good job of selectively opening the shadows. You have to know this when making the exposure in the field. In a sense you expose for post, knowing that image as it comes from the camera will be unsatisfactory, but also knowing what you can do in post-proecessing.

This is exactly the method film photographers developed to deal with the limited dynamic range of their materials. Ansel Adams was perhaps it’s most noted¬†practitioner. He called it the Zone System. He exposed the negative to make the best print, even though it might look like an underexposed or overexposed negative to a conventional film photographer. There was definitely a method to his exposure madness.

With today’s tools, you don’t have to know the Zone system: especially with Lightroom’s interactive tool set. With Lightroom, as noted above, you can see what you are doing. Changes are real time as you move the control. You see how much the highlights are brought back with the Recovery tool. You can see how much the shadows are opened with the Fill Light tool…and, just as importantly, you can see what the tools are doing to the rest of the image.

Both Recovery and Fill light flatten the contrast curve at the ends. They remap the tones at either extreme down into the range where the monitor or print medium can handle them. Overall you lose contrast, but if done carefully, it gives the appearance of expanded dynamic range. As in the image above.

Here is another example:

Run and Fall

Run and Fall

I used the same -.7EV Exposure Compensation as a starting point. As you see maximum Recovery in Lightroom still left the highlights in the water too hot…not¬†noticeable¬†perhaps, but there to my eye. And I was not able to pull the shadows under the bank out without losing the dappled sun effect on the mossy rocks. Still, it is about as good as can be done with a single jpeg exposure.

After lots of experience in Emmon’s ¬†Preserve it is becoming easier for me than it sounds, since I have learned that, with proper EV adjustment, the Programed auto on the H50 produces an excellent, well balanced, beginning exposure. If I ever switch cameras (realistically¬†when I switch cameras) I am going to have to learn to do this all over again.

And Emmon’s Preserve will be there, always willing to teach me.

This entry was posted in editing, inspiration, instruction, Lightroom, postprocessing. Bookmark the permalink.

3 Responses to Emmon’s Preserve: Learning to Expose for Post!

  1. Nice article. The problem with judging an image’s exposure on the LCD is that the LCD looks different in direct sunlight and, say, heavy shade like your image, most cameras allow the user to adjust the LCD brightness – so your results would change with an adjustment. I would strongly suggest that you enable the camera’s histogram and evaluate the exposure via it’s graphical representation. It’s a great tool, and it’s always there; at your fingertips. It’s especially important when working with a Point and shoot camera recording .jpg images.
    Probably more info. than you were looking for…
    Very best,
    Chris
    http://www.naturephotographyblog.com
    http://www.chrisdoddsphoto.com

  2. simon says:

    I seem to have a lot to come here to learn, tnk f`the sharing

  3. Pingback: 3/23/2010 « Pic of the Day

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