What if I get ISO wrong?
If you get your ISO or other settings wrong, then not to worry! There are a range of post-processing software programmes available to edit your photos, including Adobe Lightroom.
What's the difference between film ISO and digital ISO?
The main difference between film and digital ISO is that film ISO is a measure of the sensitivity of the film itself, while digital ISO is a measure of the sensitivity of the digital sensor. With film, you can't change the ISO after you've exposed the film; you're stuck with whatever you chose.
With digital cameras, however, you can change the ISO at any time. This means that you can shoot at a lower ISO when there's plenty of light, and then switch to a higher ISO when conditions get darker. This flexibility is one of the main advantages of digital over film
What about the ASA and DIN?
Prior to international standardisation, light was measured by either ASA (in the US) and DIN (in Germany. If you grew up using film cameras, you may be familiar with the ASA.
An ASA in photography is an acronym for "American Standard Association." It was a rating system used to measure film speeds and the light sensitivity of photographic films and digital sensors. The ASA rating is displayed as a number on film boxes and in the specifications of digital cameras.
The ASA rating system is a bit different to ISO. The ASA scale begins at 0, which is the light sensitivity of a very slow film, and goes up to 30,000, which is the light sensitivity of a very fast film.
ASA ratings are used to determine how long a photograph can be exposed to light without causing overexposure. For example, a film with an ASA rating of 100 can be exposed to twice as much light as a film with an ASA rating of 200.
The international ISO standards gradually replaced ASA and DIN in the late 20th century.
