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Archive for April, 2013

As discussed in parts one and two of this series, histograms are very useful for assessing dynamic range, contrast and exposure while in the field and using what histograms show to adjust camera settings. Histograms also are useful after the shot in making adjustments on your computer, referred to as post processing. As noted, this series of posts shares some excellent material from Varina and Jay Patel’s ebook, entitled “What the heck is a HISTOGRAM?”  For a more detailed discussion on how to use histograms in post processing, check out their ebook. It’s excellent!

All Schutzhund photographers struggle to conquer the ever-present challenge of properly exposing for the background and the dog. Often, these are conflicting goals, as by themselves the dog and the background more often than not require completely different settings to achieve proper exposure. And, unlike landscape and portrait photography, our subjects don’t sit still, so using HDR and bracketing techniques is not an option. Shooting in RAW, while preferable, also is not practical when shooting in burst mode, at least not in my experience.

Consider this image and its histogram:

Histograms Orig 1

Histograms Org RGB 1

The background and the dog appear to be similarly exposed; that is, the dog is not significantly darker or lighter than the background and the quality of the detail and color are compatible. The level of detail also is apparent in the histogram as the bars are tall. Yet the image is a bit dark, except for the bleachers, which are bright white. This is indicated in the histogram as the spike up against the right (highlights) wall. Most of the other pixels trend towards the left (shadows) side of the histogram.

In post-processing, histograms are helpful in adjusting contrast to bring out the color and details as well as overall dynamic range to brighten highlights and deepen shadows. In this image, the shadows are already pretty deep.

Within photo editing programs, such as Adobe Lightroom and Photoshop (the two I use), photographers make these adjustments using curves or levels tools. First step is to adjust the dynamic range by moving the white point at the top of the curve or the far right in levels and the black point at the bottom of the curve or the far left in levels “so that they line up with the outer edges of the histogram. Jay and Varina caution to be sure to watch the histogram to “avoid lost detail in the highlights or shadows. But don’t ignore the image itelf. Extreme adjustments can add unwanted noise, artifacts and banding.”

The next step is to adjust the mid-tones. In curves, adding a “simple s-curve adds mid-tone contrast without eliminating details in the shadows and highlights…Pulling the right half of the curve upward stretches the right side of the histogram outward – effectively adding contrast to the brighter tones, with out moving the white point.” Pulling the curve in the opposite direction or downward opens up the left side of the histogram “adding contrast in the darker tones without moving the black point.” In the levels tool. these same effects may be achieved by moving the middle arrow.

Which tool you use is personal preference. I prefer the levels adjustment tool, but many other photographers like the curves adjustment tool.

These adjustments can be seen both in the image and the histogram below. Notice that the bleachers have been removed and the image cropped to bring greater emphasis on the dog. The histogram shifted more towards the middle and the spike next to the right (highlights) wall is significantly reduced. There is also more detail in the highlights area that was missing in the original photo.
Histograms Adjust 1
Histograms Adjust RGB 1
When confronted with a background that is brighter than the dog or a dog that is significantly darker than the background, the best bet is to isolate each area and adjust each one separately. Consider the image below with its histogram. Both the background and the dog are very dark, yet I know from experience that if I adjust both together, the brighter areas of the dog and dumbbell will end up looking really weird, with some blown out highlights. The histogram bears out how dark the image is, yet there is a lot of detail.
Histograms Orig 2
Histograms Orig RGB 2
First step is to isolate the dog and adjust to bring the shadow area of the histogram towards the mid-tones, which will brighten up the darker areas of the dog. When I selected the dog, I did not select the dumbbell or the dogs legs and feet. They are more closely aligned with the background, so I elected to adjust them with the background. Once satisfied, inverse the selection and then adjust the background. I also used the burn tool, set on mid-tones at about 20 to 30 percent opacity, in Photoshop to fine tune the dumbbell and the tan fur on the dog’s legs. Below are the results, with the histogram at the top right:
Histograms Adjusted Image 2
The image is brighter, the dog’s face shows more detail, and the one really bright area along the dogs back leg is toned down. The dog and background look in balance. I could have brightened up the image even more, but it was taken early in the morning, so I wanted to be sure to retain the warmth of the light at that time of day. Notice how the histogram in the upper right is broader and extends into the mid-tones area, while still retaining the nice bell curve shape.

This series is just an introduction to histograms and how you can use them to enhance your photography. I encourage you to read Jay and Varina’s ebook, as well as view tutorials on the curves and levels tools. As always, thanks for visiting and Happy Shooting!

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Snow-GSD's-Carolina-V.-Johnson

With the latest (and hopefully the last) spring snow storm raging in the northern plains, I thought it would be fitting to take a momentary break from the series on histograms to feature this image taken by Carolina V. Johnson. It is an excellent example of a truly artistic photo that captures the beauty and drama of working line German Shepherd Dogs in action. Part three of the series on histograms will be posted this weekend.

So, in Carolina’s own words, here is how she got the shot. To see more of her work, please visit Carolina K9Photography.

This is a picture of Arko vom Windlied and Tara vom Kirchberghof playing in a foot of snow. This picture was not planned. My husband was playing ball with them while I took pictures of them. The following is the camera, lens and settings I used to get the shot:

Camera Used: Nikon D-80

Lens Used: Nikon AF-S VR Zoom-NIKKOR 70-300mm
F/4.5-5.6G IF-ED Telephoto Zoom Lens
Settings: Manual Setting, 1/2500 shutter speed, F/4.5 aperture, and  O EV (neutral EV)
Post-Production: I used Adobe Photoshop CS3 to resize it to smaller web size. I also sharpened it a little bit and then put my signature on it.

Do you have a really great image that you’re especially proud of or you think would be especially instructive to other photographers? Then, please send it to me , along with a brief description of what went into getting the shot, with an emphasis on planning, actually taking the photograph, including lighting conditions and other challenges, and any post-processing. Please send before post-processing and after, so we all can get a sense for your process and why you made the choices you did. Send them to bj@bjspanos.com.

As always, thanks for visiting and Happy Shooting!

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