This past week I helped my friend Jo with a wedding she was hired to photograph. Normally she wouldn’t require that help, but these times of social distancing require a bit more effort. Although I did snap a few photos, my main job was to hold a wireless flash so Jo could keep that safe distance the government is recommending. The wedding was at a beautiful rustic setting and it was hot, sunny. By adding flash she could underexpose the ambient light and allow me to place a more flattering light than the harsh sunlight on her subjects.
On my way home I thought about the harsh contrast and how easy it is to control the exposure with today’s fantastic cameras.
Digital camera sensors have a dynamic range close to five or six stops, by that I mean the range from overexposure to underexposure is about five to six stops. (Dynamic range is defined as the ability of your sensor to retain detail in the shadow area as well as detail in the highlights).
By shifting your shutter speed in Manual mode you allow light to reach your sensor for either a longer or a shorter time and by opening or closing the aperture you let in more or less light. One just adds or subtracts the numbers till you get a proper exposure. That is the basic concept.
Readers might experiment a bit by making test shots in different lighting using a neutral colored subjects like weathered wood on an old building and check their camera’s histogram after each exposure. That would give one a good understanding of how a digital camera’s meter works in Manual mode.
To expand on the concept of exposure think about this. For years I spent many weekends during the year photographing weddings. My two main subjects were one person wearing black and one person wearing white.
If I aimed my meter at the black coat the white gown might be overexposed. If I used the white subject for my exposure the black may be underexposed. My problem was that I wanted to see detail in both. The trick was to select an exposure about halfway between (actually closer to 2/3rds on the highlight side). A good rule-of-thumb one could use is, “Black is about 2 stops underexposure and white is about 2 stops overexposure”. That isn’t exact, but close enough to work with most of the time.
Digital cameras handle highlights and shadows differently than film cameras. For film cameras experts would advise us to expose for the shadows and let the highlight fall where it will. Film has an exposure range that has a gradual response in highlight and shadow areas, and it is usually possible to find detail in the highlights, however shadow detail was always a problem.
Digital cameras usually record an amazing amount of detail in the shadows, but once overexposed the detail is gone forever. Digital sensors are great until they reach the maximum value of that dynamic range. When that happens, the digital term is called “clipping”. The detail can be lost or becomes very noisy (much like grain when film is pushed too far).
When we were using film our goal was to expose for the medium tones as in mid-gray or 18 per cent (reflected) gray. We used to try exposing for the shadows to retain detail because film held detail in the highlights very well. Digital sensors are very different in the way they handle highlights and shadows. Overexposure to underexposure is much less than film and it’s easy to “clip” the highlights.
Many experienced photographers will advise that the ideal exposure is within 1/2 or 1/3 stop of highlight clipping. (The greatest possible dynamic range with both detail in the shadow areas and the highlight areas)
To do this one needs to retain control over the exposure and my advice has always been to start using the camera’s manual mode and not rely on the cameras automation. I’m not saying never use any of the automated Modes, I switch back and forth depending on what is happening. Using the Manual Mode shouldn’t be something that slows a photographer down; it should be a way of using the camera that helps control light, shadow and the way one exposes the subject.
Stay safe and be creative.
These are my thoughts for this week. Contact me at www.enmanscamera.com or emcam@telus.net.
