Tag Archives: high

Exposure Blending – A Quick Overview

August 2, 2011 G Dan Mitchell 12 Comments

(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.

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Commentary, Locations

Yosemite High Country – A Brief Late July Report

July 30, 2011 G Dan Mitchell 1 Comment

Carefully timing my visit to miss the weekend crowds, I spent the better part of the last week of July (2011) in the Yosemite National Park high country along and around Tioga Pass Road. I posted the first photograph from this visit earlier today, and more will appear here soon. But while the visit is still fresh in my mind, I thought I’d share a few observations and comments that might be useful to others heading there or to other parts of the high Sierra soon.

In a typical late July, all of the snow is melted out at “campground elevations” (generally 8000′ – 9000′ or so – Tuolumne Meadows is at 8600′), essentially all of the usual high country areas are accessible by trail or cross-country travel, wildflowers are at or near their peak, mosquito populations have reached their peak, and visitors are starting to arrive en masse for day use, camping, and backpacking. With the exception of the influx of visitors, this is not quite a typical season, however.

Snow – As I drove up Tioga Pass Road on July 26, the first surprise was finding that there were still large snow patches in some forested areas as low as 8000′ or so. I don’t recall seeing this much snow so low so late in the season in the past. (My memory may not include the lower elevations at this time of year in 1996, the last year with such impressive snow fall.) I stayed at the Porcupine Flat campground, and at least one site there still had enough snow as to make it pretty unusable. Continue reading Yosemite High Country – A Brief Late July Report →

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

Trees in Silhouette, Olmsted Point, Sunset

June 29, 2011 G Dan Mitchell 1 Comment

Trees at Olmsted Point are silhouetted against a brilliantly colorful spring sunset sky, Yosemite National Park.

I think everyone should occasionally get to post a just plain gaudy color sunset – and this is mine. While photographing Mount Conness from Olmsted Point was my primary goal on this evening, I also had some opportunities to swing the tripod around and point at other things from time to time. This is about as close as I can come to capturing the nearly hallucinogenic color of the sky as the brightest cloud illumination was centered directly overhead and beginning to move off to the west.

The color saturation was so intense that I had to under expose this by at least a stop in order to avoid blowing out the red channel and in order to retain some differentiation among the various shadings of color as they transitioned from very pink/red through orange and purple and on towards blue.

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

Lodgepole Pine, Evening Shadows

May 29, 2011 G Dan Mitchell Leave a comment

The evening shadow cast by a nearby high ridge approaches a lone lodgepole pine and an old snag near Tioga Pass, Yosemite National Park.

One of my favorite kinds of light is that found at the edges of shadows from higher peaks as they move across lower terrain. (A secret: Among other “tricks,” I like to find and follow these margins when I shoot in Yosemite Valley, too.) Because this light most often happens during the relatively early and late hours of the day, the color quality of the light tends to be warm and the angle low. As the patterns of light and shadow move across the landscape, individual elements may get picked out the light and can often be isolated against darker backgrounds, as in this photograph.

The Sierra is full of trees pretty much like this one, and such meadows with the isolated small and large trees and scattered boulders are not hard to find. This particular tree is in one of the extensive meadow areas in the general area of Tioga Pass. The photograph was made in the very late afternoon as the tall ridge to the west was blocking the sun.

Despite the still and tranquil nature of the scene, this is an example of a sort of shot that reveals the wrongness of the idea that all landscape is done slowly and methodically and with all the time in the world to work. Sometimes that is the case, but when you work the margins of shadows (or many similar dynamic subjects) there may only be brief seconds when the light is where you want it. An observer might find it humorous to watch the photographer run to get into position and then work very quickly.

Photographer and visual opportunist. Daily photos since 2005, plus articles, reviews, news, and ideas.