Technical Stuff – Exposure and Hyperfocal Distance

I was not at all happy trying to second guess the exposure using the printed chart so pretty soon I bought a second-hand exposure meter which filled in until I could afford a Weston Master V.

Made by Sangamo Weston in Enfield, North London, these were the professional photographer’s preferred meter. You set the film speed on the dial, in either ASA (American) or DIN (European) rating, and pointed the other side of the meter, where the photo cell was situated, at the subject to read the level of light reflected from it. Setting the red pointer against the number taken from the scale gave you the shutter speed and aperture combinations required to give the perfect exposure, or so you hoped. You never really knew what you had got until the film was developed and this was one of the exciting aspects of photography at that time.

Today, when just about every camera has auto-focus, it must seem quaint that my Halina camera had no built in means of measuring the point of focus whatsoever. You had to guess the distance and set it on a scale on the top of the lens. As I rarely photographed anything close, I used ‘hyperfocal distance’ to ensure my pictures were sharp and indeed, still do to this day with my digital Leica.

The ‘depth of field’ is the depth in front of and behind the set distance which will be sharp. This is shown above on a modern day Leica lens. The sharp area will be between the distances that line up with the set aperture. Left hand picture: With the focus point, top centre, set to infinity, the picture will be sharp from infinity to the distance which is read off next to the aperture in use. In this case it is f11 and the distance is 4 feet. Right hand picture: With the infinity point now set to f11 at the other side of the lens, the picture will be sharp from infinity to 28″. As the lens shown is a very wide angle 21mm lens, the depth of field is very wide in any event. The same exercise with a 50mm standard lens would give you an increase in depth of field from infinity to 25 feet to infinity to 10 feet.

My music business pictures are available at Getty Images and on my own website