ISO from my A-Z series

The initials ISO stand for the International Standards Organisation.

Of which I am sure we have all heard of, because they set the standards for so much of the modern world!

When camera film was being developed, each company set their own standard, by this I mean the sensitivity to light and the way the film reacted to light. And of course, this was only monochrome film, colour film took a long time to develop and become popular.

A guy called Oskar Barnack, who worked for Leica, took standard cinematic film and mounted it horizontally for the first time, in 1913. This idea was so popular that it became the standard. The majority of camera manufacturers adopted it over time. To facilitate this, there had to a common standard for the actual film. When I started photography in the early 1970s, I bought 100asa or 400asa film. The 100asa had a much finer grain to it, and to me a more pleasing result. Its also worth noting that the photographic paper that the image was printed onto, was very influential on the final image.

ASA, the American Standards Agency, was eventually subsumed by ISO. Colour film came along, now with a standard reactivity to light, set by the ISO. The electronic sensor was invented in 1969 and the first camera using a digital sensor was a Canon in 1986. All the camera manufacturers were working towards this, and they had to have a common standard for the sensitivity of their sensors – ISO!

In 2025 we have the most extraordinary pieces of exquisite engineering. We can take photos of the stars, of people in the near dark and full sunlight. The lowest figure for ISO for a lot of cameras is still that magic 100 number, this used to give the highest image quality with the least noise. My current camera goes up to 64,000, but that gives quite poor image quality, but its a photo in the almost complete darkness. ISO is one of the three basic or fundamentals of photography, these are the axiomatic three. ISO, shutter speed and aperture, each is variable to give the effect that the photographer is trying to achieve. The skill of balancing ISO, aperture and shutter speed are still the key skills of the professional photographer. I have selected these photos to demonstrate the difference in ISO, the first image of a lady outside the bar, and the second, the church in Souiesh, France, are taken a 64,000 ISO, with a shutter speed of half a second, the third image of some poppies is the absolute opposite, 100 ISO and a very high shutter speed because of the intense sunlight. Understanding the link between ISO, aperture and shutter speed, allows the professional photographer to make the best possible image, in the worst of circumstances!

Unfortunately, I can only add one image in the blog post!

#beautifulportraitsforbusyprofessionals