Things that Make Photographers Cry
A selection of confusing, fun, and technical topics about photography
The Hyperfocal Distance
Who?!—What sort of hype are we talking about?!
Well, this is the focal distance to maximize the depth of field, for a given Aperture. In practice, the hyperfocal distance is usually used with smaller apertures to get as much as possible in focus.
For technical people, the—in principle—very simple formula: H = f^2/Nc + f, for practical purposes the simplified version will suffice: H = f^2/Nc, with hyperfocal distance (H), focal length (f), f-number (N), and circle of confusion diameter limit (c).
Many lenses have the range to select the hyperfocal distance indicated on them.
Opposite to that, an image with similar focussing distance, but different focal length and large aperture.
Headache? But we haven’t even started, yet ;)
The Schwarzschild Effect
Photographers might smirk nostalgically, shed another quiet tear about their favorite negative film, or boast into rants either why digital rulz over film or why one can never truly understand photography without having experienced film.
This one, while not relevant in the digital photography age, is excellent to nerd out amongst fellow photographers.
The Schwarzschild effect (aka reciprocity failure of exposure time) can usually be observed when using film to capture scenes with long exposures. Reciprocity means the linear behavior of exposure time and the amount of light registered by the film: Half the exposure time, half the registered light, double the exposure time, double the light. This, however, breaks down with very long exposures (Schwarzschild effect). In landscape photography with small apertures or night photography, exposures often go far beyond 10 seconds.
At its core, exposing film is a chemical reaction. These reactions are getting exponentially slower, the less light they receive. Depending on the film, this could result in the following example:
This differs depending on the film type. For the ultimate nerd-out, point someone who is complaining about the Schwarzschild effect to Kodak’s BW400CN black and white film, which is reciprocal way over 100 sec. (with color films you might be out of luck, though).
Not crying, yet? Please do keep reading on :D
Megapixel vs bits per Color Channel vs Color Rendering
Three false statements in practical photography: The more megapixel (MP), the sharper the image—the more bits per color channel, the better the colors—the more dynamic range, the better the picture quality.
People are usually surprised when they hear most of my pictures are taken with a 10 MP camera. Why is the 46 MP smartphone blurrier?! Why do 24 MP compact camera pictures not “look as good”?
The difference here makes the lens and this is why many professional photographers invest in lenses first and in cameras second.
12-bit RAW, 14-bit RAW, 16-bit TIFF?! This goes hand in hand with dynamic range of digital photographs. In theory, more bits per color channel mean finer color nuances, deeper blacks, and wider highlights. This is, however, only true when colors are rendered naturally.
Color rendering goes into the realm of psychology and is also depends on cultural environments. This lead to films having slightly different color properties depending on the country they were sold in.
With digital photography, color rendering is mostly a matter of software. Some in-camera conversions are famous for excellent color rendition, such as recent cameras from Fujifilm.
To be continued..., as there is so much more fazing stuff out there about photography ;)