Digital Photography Cheats Physics
As I wrote this it went from a quick and simple post into one that’s too big for a single post so I’m going to spilt this into 2 posts. Part 2 will come tomorrow.
Part 1
With that headline all of the engineers and matamaticians out there must be thinking I’ve gone off the deep end. Well of course we’re not breaking the Laws of Physics because …. well …. because they are the Laws of Physics and cannot be broken. This is simply a way of organizing three somewhat disparate digital photography techniques into one bucket. So it’s not so much a tip or anything that you can use directly but simply a different way of thinking of things.
Back in film days, before desk top scanners, there were four areas that photographers were limited in by the physics of light and lenses. They struggled to overcome these limitations:
- Image Detail (Resolution)
- Angle of View
- Dynamic Range
- Depth of Field
In order to capture more image detail film photographers resorted to using medium or large format cameras to capture the same subject/scene on a larger piece of film. But this meant carrying around large heavy bulk equipment.
While it’ is true there were dedicated panoramic film cameras they were specialized, expensive, and limited by their fixed format (aspect ratio). As such they were “specialty” items and were not very popular.
To overcome the limited dynamic range range of their film, photographers utilized Graduated Neutral Density filters. This allowed them to darken the bright sky, relative to the darker foreground, and to compress the dynamic range of light in the scene to a range that could be captured on film. The person who’s images popularized the use GND filters was the late Galen Rowell. (The link is to his bio but while you are there check out some of his images. And remember, these were captured with 35m film! In fact Sing-Ray GNDs, the “gold standard of grad filters”, were developed with Galen.)
To over come the limited Depth of Field film photographers resorted to the use of lenses that tilted (or to a view camera that allowed the whole lens to be tilted). This tilted the image plane so that more of the scene would fit in the available DOF.
Then came along digital imaging and photographers started to use the digital darkroom to over come these same limitations. Three tools or techniques that are used to overcome the above limitations are:
- Stitching Software
- Focus Blending
- High Dynamic Range (HDR) Photography
(While some of these digital techniques could be replicated by the VERY best wet darkroom experts like, Jerry Ulsmann , most of us could not even begin to replicate what we can easily accomplish in the digital darkroom.)
Tomorrow I’ll post some examples of these techniques in Part 2.