I’ve seen the abbreviation a lot lately – it’s properly been around forever, but I just haven’t noticed it, before now – and didn’t know what it meant exactly. I figured it had something to do with Exposure. Well, Google is your friend, when there are things you don’t know.

EI is short for Exposure index, and that is the indication of which you shot your film at. Ex an 400 film shot at 200, will be EI 200.

Normally written like this: Kodak Portra 160 (EI 80)

NB: ISO means the International Organization for Standardization and indicates the light sensitivity your film is rated as.

From this post and forth, I will also use it on my blog 🙂

Here another example.

Camera: – Film: HP4 (ISO 400, EI 50)

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