Sunny 16 Rule Calculator
Gives the shutter speed for bright sunlight from film or sensor ISO, starting at 1/ISO second at f/16 and rescaling for whatever aperture you pick.
Obturador (s)
—
Sunny 16: exposure without a meter
The Sunny 16 rule lets you expose a frame correctly with no light meter at all. Bright daylight? Set f/16 and a shutter speed of 1/ISO seconds. So at ISO 100 you'd shoot 1/100 s at f/16, or the nearest stop your camera has, 1/125 s. When clouds roll in you open the aperture: f/11 for slightly overcast, f/8 for overcast, f/5.6 for heavy overcast or open shade, f/4 at sunset, and f/2.8 for backlit subjects. Reciprocity is what keeps the exposure the same as you move across stops: 1/100 @ f/16 = 1/400 @ f/8 = 1/1600 @ f/4 — the total light is identical, only the depth of field and motion blur change.
Applications
It earns its keep in film photography, on older bodies that never had a built-in meter like the Leica M3 or a Holga. It's a backup when metering fails too, say a dead battery or a high-contrast scene that throws the meter off. Teachers lean on it in photography classes to get the exposure triangle into students' heads, and it gives you a fixed reference in full manual mode (MTM) when you'd rather not hand the decision to auto exposure.
FAQ
Does it work at any latitude? It's tuned for sunlight between 10 am and 4 pm at mid-latitudes. Near the equator or up in the polar regions you'll have to adjust by feel.
And in winter snow or beach? Surfaces that reflect a lot of light throw the rule off, so stop down +1 stop (go to f/22) or the bright surface blows out.
Is it accurate enough for slide film? Negative film forgives a lot, around ±2 stops of latitude. Slides like Velvia or Provia don't, so treat Sunny 16 as a starting point and bracket your shots.
Related Tools
Composite Modulus (Rule of Mixtures)
Calculate the longitudinal elastic modulus of a composite by the rule of mixtures, E_c = E_f·V_f + E_m·(1 − V_f), from the fiber modulus (E_f), the fiber volume fraction (V_f) and the matrix modulus (E_m). The result, in the modulus unit (GPa), is the modulus in the fiber direction (Voigt upper bound), assuming equal strain in fiber and matrix. It shows the composite stiffness is a volume-weighted average — stiff fibers (carbon, glass) at high fraction greatly raise the modulus. In the transverse direction, the inverse rule of mixtures (Reuss bound) applies, much lower. Enter the fiber modulus, the fiber fraction and the matrix modulus.
1% Rule Check for Rental Property
Enter monthly rent and purchase price to get the rent-to-price percentage and see whether the deal clears the 1% rule used to screen rentals.
Fiber Volume Fraction
Calculate the fiber volume fraction of a composite, V_f = (W_f/ρ_f) ÷ [(W_f/ρ_f) + (W_m/ρ_m)] × 100%, from the masses (or mass fractions) and densities of the fiber (W_f, ρ_f) and matrix (W_m, ρ_m). The result, in %, converts the mass composition (easily measured) into the volume composition, which determines the composite's mechanical properties by the rule of mixtures. Fiber volume fraction is a laminate's most important parameter: the higher it is (up to the packing limit, ~60-70%), the greater the stiffness and strength in the fiber direction. Enter the fiber and matrix masses and densities.
Rule of 72 (Investment Doubling)
Estimate years needed to double an investment at an annual rate using the classic Rule of 72. Compare with exact (ln 2 / ln(1+r)).
50% Rule for Rental Expenses
Applies the 50% rule to a monthly rent: half is assumed to go on upkeep, vacancy and management, and the remainder is shown as monthly net operating income.
Pediatric Dose (Clark Rule)
Compute pediatric dose by Clark Rule: child = (weight_lb / 150) × adult dose.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.