Miscellaneous / Blog / 20060926
On the Topic of Spacing Exposures During Bracketing
One primary focus of our upcoming trip to Utah is stitching photos to get more resolution. Using stitching in combination with exposure bracketing is going to result in a huge number of exposures. So I did a test of just how many exposures are necessary and what exposure spacing yields good results.
Below is the somewhat developed test image, which is not completely finished in terms of development (ie, see the huge lens hair). Seven exposures were used to produce the blended digital negative used in this image. The shots were taken using at 17mm and f/11 with exposure shutter time of 1/45, 1/20, 1/10, 1/6, 0.3, 0.7, and 1.5 seconds.
A 100% over-sharpened crop of the outlined strip is below. Each section of the strip shows the resulting developed image produced from a certain range of exposures. Notice the huge noise problem with just a single exposure, or even two exposures. It takes the first 6 exposures to produce a noise free image in this case. Skipping every other exposure (see the exposure 1+3+5+7 strip) results is a small amount of noise. While only using the lightest, darkest, and middle exposure yields a large amount of noise. So skipping exposures is probably a bad idea.
