OK. You understood what f/number is, what ISO is and what shutter speed is. Also, you can use ND filters occasionally. But when you have to find an equivalent combination between shutter speed - aperture - ISO it is not easy for you.
With this chart it is! It gives you choices among the various aperture–speed-ISO-ND filter combinations that result in the same exposure. The only thing you have to do is add the helios that match each value to find the total. Then, every same total will give you an equivalent combination.
Let's see an example: All of us know the famous "Sunny 16 rule". According to this rule in a sunny day we can use the following values: Aperture f/16 - Shuter speed 1/125 sec - ISO 100. At the Helios Exposure Value Chart these values lead to a total of 16 (4 for f/16 + 9 for 1/125 sec + 3 for ISO 100). Every total 16 leads to an equivalent combination (the same amount of light). So, if we choose f/4 - 1/4000 sec - ISO 200 (8 for f/4 + 4 for 1/4000 sec + 4 for ISO 200) the total will be again 16.
If you want, for example, to photograph waterfalls and you need a slow shutter speed in order to produce the classic blurred effect you can use a ND1000 filter. In that occasion you have to subtract 10 selenes so you can achieve the 16 helios in such a way: 8 for f/4 + 14 for 1/4 sec + 4 for ISO 200 -10 for ND 1000 (total 16).
It is simple, isn't it?
With this chart it is! It gives you choices among the various aperture–speed-ISO-ND filter combinations that result in the same exposure. The only thing you have to do is add the helios that match each value to find the total. Then, every same total will give you an equivalent combination.
Let's see an example: All of us know the famous "Sunny 16 rule". According to this rule in a sunny day we can use the following values: Aperture f/16 - Shuter speed 1/125 sec - ISO 100. At the Helios Exposure Value Chart these values lead to a total of 16 (4 for f/16 + 9 for 1/125 sec + 3 for ISO 100). Every total 16 leads to an equivalent combination (the same amount of light). So, if we choose f/4 - 1/4000 sec - ISO 200 (8 for f/4 + 4 for 1/4000 sec + 4 for ISO 200) the total will be again 16.
If you want, for example, to photograph waterfalls and you need a slow shutter speed in order to produce the classic blurred effect you can use a ND1000 filter. In that occasion you have to subtract 10 selenes so you can achieve the 16 helios in such a way: 8 for f/4 + 14 for 1/4 sec + 4 for ISO 200 -10 for ND 1000 (total 16).
It is simple, isn't it?
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