Metering issues

In the 90's I photographed baby harp seals on pack ice near the Magdallen Islands, Nova Scotia in Canada. I was flown out onto the ice by helicopter, and it was a brisk minus 45 degrees Fahrenheit. At the time, my film camera was the medium format Mamiya RZ 67. I took all of the light readings with a hand-held Sekonic L-608 meter. With digital cameras, we can see what the exposure is on the back of the camera. In the past, though, you had to be right-on without seeing any results until the film was developed. How old fashioned! Most of the time, I used the 'incident mode' on the meter. This measured the light falling onto the scene, not the light being reflected from it. Incident readings require no tweaking because they are consistently accurate, but reflected readings -- such as what our digital cameras rely on -- aren't accurate when shooting extremely bright subjects, like snow, or very dark subjects, like a black dog at night. That's why you have to constantly check the LCD monitor to see if your exposures are correct. If not, use the exposure compensation feature to add or subtract light until the photos are perfect.