0.9 how many stops

When you stack filters you only have to add the values rather than multiply, as one does with filter factors. But you kids don't use colour filters, do you? Trust me, if you use external meters and shoot film, density values are easier in the field. Stan: Yeah, logarithmic makes more sense, but it's always bugged my that "density" is expressed as a logarithm of 10, whereas everything else in photography is expressed as a logarithm of 2, like f-stops.

It seems Log10 density is used in the lab for measuring film, sensors, attenuators, and the like. But in the field when taking pictures we use Log2 f-stops. I don't understand why filters aren't rated more relevant to their end use, which would be in f-stops of attenuation. When adjusting a camera, "3 f-stops" is more immediately useful than a factor of 8 or a density of 0. I've seen an ND16 filter - they're used in higher-end microscopes this same unit had integral ND4 and ND8 filters as well.

Certainly uncommon in photography, though. Amudgarden Amudgarden 1 1 silver badge 5 5 bronze badges. There are two common ways of quoting ND filter strengths, and one less common: 2x, 4x, 8x, etc.

Stacking multiple ND filters adds stops, and multiplies strength values. Michael C Michael C k 9 9 gold badges silver badges bronze badges. Example: ND1. Bruno Bruno 1 1 1 bronze badge. Sign up or log in Sign up using Google.

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Submit your photo Hall of fame. Featured on Meta. Now live: A fully responsive profile. Version labels for answers. Linked 0. Related 5. Hot Network Questions. Question feed. Photography Stack Exchange works best with JavaScript enabled. Accept all cookies Customize settings. Leonard Migliore's gear list: Leonard Migliore's gear list. Leonard Migliore wrote: plevyadophy wrote: Now I have a related maths question. Oh well, bang goes my idea of a simple formula Season's Greetings.

Oh well, bang goes my idea of a simple formula Season's Greetings As already said, it's probably easier to memorise the numbers rather than try to calculate it from a formula.

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This system is different from stock trading which only applies during business hours according to the regulations of the stock exchange authorities in each country. In forex trading, there is no official reference for determining currency values, it all depends on the strength of supply and demand. Indeed, in some cases, a number of parties can influence the movement of forex trading.

However, to move the market requires very large funds. Several things that affect foreign exchange prices include interest rates, oil prices, as well as geopolitical and economic conditions. As an illustration, when the Federal Reserve Banks or the Central Bank of the United States wants to attract the dollars circulating in the world to return to their countries, they will raise their benchmark interest rates.