I just thought that I would report that around thirty something people attended my class last night. All brought real cameras, not cell phones, and before the class ended I made sure everyone could change these settings and change shooting modes and understood how each worked. This is a handout I made that each person received that I hope helps them understand the different settings and how the affect the photo they are taking. I made all settings one full stop apart so it would be easier to relate how each of the setting affected the amount of light. I left out the in between settings to keep it easier to follow and cut down on confusion. I received a lot of positive feedback and managed to get everyone in the class feeling a lot more comfortable with taking more control of their camera. I think everyone had a good learning experience and I am looking forward to my next class in the future.

I hate to belabor a point, but here again, wording is important for your students' ultimate understanding. Your slides aren't functionally wrong, just slightly misleading and inaccurate.

Changing ISO does not amplify or attenuate LIGHT. It changes the volume of LIGHT *required* to make the exposure.

In the film world, changing ISO by changing film stocks changes the size of the silver salt grains in the emulsion.

In the digital world, it merely changes one or both of these two things — the analog electrical signal coming from the sensor is amplified or attenuated before it is digitized, and/or the range of values used to process the image is altered (for example, the highlight level is set lower, raising all the other values on the scale). Even that is a gross oversimplification, but sufficient for most to understand that the process occurs immediately after image capture and before the file is processed to an image or saved as raw data.

Only two variables comprise the actual EXPOSURE: Aperture and Time.

Two other variables affect *how much* exposure is needed: The volume of light available to make the exposure, and the film or sensor sensitivity. Sensitivity (ISO) sets the absolute volume of light required for a proper exposure (How many photons of light do we need for a full tonal scale?). The amount of light on the scene *and* the sensitivity factor together to set the Exposure Value, or the match up of the f/stop and shutter speed scales.

We tend to confuse ISO with exposure, because digital cameras allow varying the ISO for each exposure, and may even include auto ISO with both manual and auto exposure modes.

Here's a bit of interesting trivia: Many folks assume ISO is an acronym. That is incorrect, but understandable due to the derivation of the film speed scale used in ASA, which WAS an acronym — for the American Standards Association (now ANSI).

A few decades ago, when the major film manufacturers started to change their sensitivity scale over to ISO, prominent writers in the photo industry trade press failed to mention the correct pronunciation, or even look it up. I heard them on trade show floors like the old PMA, talking about I-S-O, making an innocent assumption.

The standards setting body is the International Organization for Standardization:

"It's all in the name:

Because 'International Organization for Standardization' would have different acronyms in different languages (IOS in English, OIN in French for Organisation internationale de normalisation), our founders decided to give it the short form ISO. ISO is derived from the Greek isos, meaning equal. Whatever the country, whatever the language, we are always ISO."

Source: https://www.iso.org/about-us.html

The name gets right to the heart of the organization charter: Helping everyone measure the same things the same way.

Give us a break, burkphoto. Quote what the organization itself says:

"It's all in the name
Because 'International Organization for Standardization' would have different acronyms in different languages (IOS in English, OIN in French for Organisation internationale de normalisation), our founders decided to give it the short form ISO. ISO is derived from the Greek isos, meaning equal. Whatever the country, whatever the language, we are always ISO."

ISO IS TOO an acronym.

Give us a break, burkphoto. Quote what the organization itself says:

"It's all in the name
Because 'International Organization for Standardization' would have different acronyms in different languages (IOS in English, OIN in French for Organisation internationale de normalisation), our founders decided to give it the short form ISO. ISO is derived from the Greek isos, meaning equal. Whatever the country, whatever the language, we are always ISO."

ISO IS TOO an acronym.

Give us a break, burkphoto. Quote what the organization itself says:

"It's all in the name
Because 'International Organization for Standardization' would have different acronyms in different languages (IOS in English, OIN in French for Organisation internationale de normalisation), our founders decided to give it the short form ISO. ISO is derived from the Greek isos, meaning equal. Whatever the country, whatever the language, we are always ISO."

ISO IS TOO an acronym.