Tag Archives: exposure

Photographs: Nature, Photographs: Northern California, Photographs: Sierra Nevada, Photographs: Yosemite

Water and Granite, Tuolumne River

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Water and Granite, Tuolumne River
Water and Granite, Tuolumne River

Water and Granite, Tuolumne River. Yosemite National Park, California. September 16, 2011. © Copyright 2011 G Dan Mitchell – all rights reserved.

Swift water flows over granite along the bank of the Tuolumne River, Yosemite National Park.

In this section of the Tuolumne River – as in many other places throughout the Sierra Nevada – the river passes through a steep section and across granite slabs that span the full width of the river. As the water flows over the granite it forms constantly changing patterns of rock and whitewater that can only be predicted in general ways. The spot included in the photograph was right along the edge of the river, and you can see the transition between the diminished flow along the bottom edge and the faster and more abundant water in the main channel beyond.

Part of the fun of shooting this sort of subject – and shooting it is a pleasant way to spend an hour along the river – is in trying to find workable compositions in such a changeable subject. And making it even more “fun,” the shutter speed becomes an important decision as it determines just much the image is affected by motion blur and how much of the scene is stopped. Fortunately, digital cameras make this process just a bit more predictable and productive, since they allow the photographer to quickly see the result of composition and shutter speed choices and verify whether or not the educated guesses were correct, and to see just how the infinitely variable and unpredictable patterns of flowing water come together at the instant of exposure.

G Dan Mitchell is a California photographer whose subjects include the Pacific coast, redwood forests, central California oak/grasslands, the Sierra Nevada, California deserts, urban landscapes, night photography, and more.
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Text, photographs, and other media are © Copyright G Dan Mitchell (or others when indicated) and are not in the public domain and may not be used on websites, blogs, or in other media without advance permission from G Dan Mitchell.

Photographs: Imaginary Landscapes, Photographs: Northern California, Photographs: Ocean & Coast

Surf, Rocks, and Horizon

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Surf, Rocks, and Horizon
Surf, Rocks, and Horizon

Surf, Rocks, and Horizon. Point Lobos State Reserve, California. April 26, 2009. © Copyright 2011 G Dan Mitchell – all rights reserved.

An imaginary landscape from surf, rocks and horizon at Point Lobos State Reserve, California.

I refer to photographs like this one as “imaginary landscapes” – though I suppose that this one is actually an imaginary seascape. The boundary between these photographs and my Regular Old Garden Variety Landscapes is a bit nebulous, but it relates to how far and how intentionally the interpretation of the scene departs from what might be regarded as its objective reality. In this case, some things were done at the time of exposure and some other things were done in post that make this image more obviously a subjective interpretation of the scene than might be the case with many of my other photographs. But you could see that by looking at it, right?

In any case, this is a single photographic “capture” made with a long exposure time that was extended by the use of a nine-stop neutral density filter – and this is what creates the majority of the soft quality of the image. Some additional work was done in post to further manipulate the original image – work with saturation and certain ways of diffusing portions of the image and so forth. In the end, little of that matters beyond the fact that these techniques were ways of producing the image that I had in mind, and which I intend to evoke something about the nature of the real scene upon which it is based.

G Dan Mitchell is a California photographer whose subjects include the Pacific coast, redwood forests, central California oak/grasslands, the Sierra Nevada, California deserts, urban landscapes, night photography, and more.
Blog | About | Flickr | Twitter | Facebook | Google+ | 500px.com | LinkedIn | Email

Text, photographs, and other media are © Copyright G Dan Mitchell (or others when indicated) and are not in the public domain and may not be used on websites, blogs, or in other media without advance permission from G Dan Mitchell.

Technique

Exposure Blending – A Quick Overview

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(This is a slightly modified version of something I wrote as part of a discussion on Google+)

The author of the post that I read before writing this mentions two alternatives for dealing with dynamic range issues in landscape scenes – the use of graduated neutral density (GND) filters or the use of a similarly-named post process technique in Lightroom. (Similar processes are available in other software including Photoshop/ACR.) Another alternative is to use HDR (High Dynamic Range) techniques that allow computer algorithms to combine source images in ways that are not the same as what I describe in this post. I almost always use a different approach, exposure blending, and I’d like to share a few ideas on this topic.

When the scene contains an extremely large dynamic range – a common situation in landscape photography – it is possible to end up with shadow areas that are nearly black and devoid of detail, along with bright areas that are blown out and also completely lack detail. (The latter is especially an issue with digital capture in which overexposed areas can simply become pure white. Film failed more gracefully in this situation.)

One traditional method for dealing with such scenes is to attach various types of graduated neutral density (GND) filters to the front of the lens. These filters include a clear area and an area darkened by a few stops. A typical use might be to position the dark portion over the sky and the clear section over a darker foreground, effectively reducing the dynamic range of the light reaching the sensor by reducing only the brightness of the sky. With film, especially positive transparency film, this was just about the only realistic way to handle the situation in many cases.

A second method is to make a single exposure and use features in Photoshop/ACR, Lightroom, or other software to simulate the effect of the GND, lightening (or darkening) a portion of the photograph. This can often help quite a bit when it comes to balancing out dark and light areas in the image, and the fact is that most savvy landscape photographers do this sort of thing and more in post. But it has its limits. For example, darkening a bright area cannot put detail back in blown out areas, and lightening underexposed shadows can lead to problems with noise and posterization. The bottom line is that this technique works well when the overall range 0f brightness in the scene does not exceed the dynamic range of the camera – here it may be used to adjust the relative levels of the areas – but it does not work well when the dynamic range is actually too great for a single normal exposure.

There is a third method, sometimes called exposure blending, that can often be used when making the exposure. The idea is to make more than one exposure, with each exposure optimized for different parts of the scene by varying shutter speed, and then selectively blend the two exposures during post-production.* Two exposures are sufficient in almost all cases, with one for the shadow detail and the other for highlight detail – though in very complex or wide dynamic range situations more exposures can be used. Continue reading Exposure Blending – A Quick Overview →

Commentary, Ideas, Thinking Aloud

Brief Thoughts on The Life of a Photograph

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The image I posted earlier today both here at the blog and on Google+ got me thinking about the various ways that a photograph can “come to life.” This particular image followed a path that several other images that I consider to be among my best followed – namely, it languished in my raw file archive for nearly a year before I rediscovered it recently while going back through the old files. I recognized this pattern some time ago, and I now make it a habit to revisit all of my (thousands and thousands of) raw files about a year after I shoot them.

Why didn’t I “see” this image when I first reviewed raw files right after the shoot? I’m not entirely certain, but several ideas come to mind. Sometimes at the time of the shoot I have a strongly fixed notion of how I want to portray the subject , and as I shoot I’m already categorizing exposures by how well they correspond to this preconception. So when I initially go through the raws I may be mostly looking for what fits my expectations as opposed to looking objectively at what works on its own merits. Coming back a year later allows me to better see the image for what it is, without having my judgment so affected by prior expectations.

Related to this is the sheer number of images and how one deals with them in the post-processing workflow. I may begin with what I think are the most promising couple of images from a shoot and then take them all the way to a print-ready (or actually printed) stage. Once I’ve done that with the first selects from a given subject, I’m more likely to move on to other subjects – and potentially leave other good images in the dust.

There is a lot more to say about this, I think, but I’ll save the longer explication for another blog post in the future. Does anyone else make a practice of doing a full review of raw files at some future date?