Exposure Value EV Calculator
Free Exposure Value EV Calculator for creative & design. Free online tool with accurate results using verified formulas.
Calculator
Adjust values & calculateEquivalent Exposures
Formula
EV is the base-2 logarithm of the ratio of the aperture squared to the shutter speed. Each integer EV step represents a doubling or halving of light. ISO adjustments add log2(ISO/100) to the base EV100 value.
Last reviewed: December 2025
Worked Examples
Example 1: Sunny Day Outdoor Exposure
Example 2: Indoor Portrait with Available Light
Background & Theory
The Exposure Value (ev) Calculator applies the following established principles and formulas. Computers represent all information using binary, a base-2 number system consisting solely of the digits 0 and 1, each called a bit. Because long binary strings are unwieldy, programmers routinely use octal (base 8) and hexadecimal (base 16) as compact shorthand. Converting between bases follows a consistent algorithm: divide the source number repeatedly by the target base, collecting remainders in reverse order. Hexadecimal digits A through F represent the values 10 through 15, allowing a single character to encode four binary bits, making it the preferred notation for memory addresses, color codes, and bytecode. Bitwise operations manipulate individual bits within integers. AND produces a 1 only when both input bits are 1, making it useful for masking. OR produces a 1 when either bit is 1 and is used for combining flags. XOR flips bits that differ, enabling simple toggle logic and efficient swap algorithms. NOT inverts every bit (one's complement), while left and right shifts multiply or divide by powers of two in constant time. Data storage units ascend in binary multiples of 1024: 8 bits form one byte, 1024 bytes form one kibibyte (KiB), 1024 KiB form one mebibyte (MiB), and so forth. Hard-drive manufacturers historically use decimal prefixes (1 KB = 1000 bytes), creating the persistent confusion between binary and decimal interpretations of the same label. The IEC standardized the binary prefixes KiB, MiB, GiB, and TiB in 1998 to resolve this ambiguity. Network bandwidth is measured in bits per second (bps), most commonly megabits per second (Mbps) or gigabits per second (Gbps). A 100 Mbps connection transfers 100 million bits every second, equating to roughly 12.5 megabytes per second. IP subnet masks define network boundaries; CIDR notation appends a prefix length (e.g., /24) to an address, indicating how many leading bits are fixed. A /24 subnet contains 256 addresses with 254 usable hosts. Algorithm efficiency is described using Big-O notation, which characterises the worst-case growth of time or space relative to input size. O(1) is constant, O(log n) is logarithmic (binary search), O(n) is linear, and O(nยฒ) is quadratic. Cryptographic hash functions like SHA-256 produce a fixed 256-bit (32-byte) digest regardless of input length. File compression algorithms exploit statistical redundancy to reduce storage footprint, and compression ratio equals the original file size divided by the compressed size.
History
The history behind the Exposure Value (ev) Calculator traces back through the following developments. The conceptual foundation of modern computing traces back to Charles Babbage, whose Analytical Engine design of 1837 introduced the idea of a general-purpose mechanical computer with separate storage and processing units, including what he called the Store and the Mill. Ada Lovelace wrote what many consider the first algorithm intended for machine execution while annotating a translation of Luigi Menabrea's account of Babbage's work, also recognising the machine's potential to manipulate symbols beyond mere numbers. George Boole published "The Laws of Thought" in 1854, formalising a two-valued algebra of logic that would later map perfectly to electrical circuits. It remained largely a mathematical curiosity until Claude Shannon's landmark 1937 master's thesis demonstrated that Boolean algebra could describe switching circuits, laying the theoretical groundwork for all digital electronics. Shannon's 1948 paper "A Mathematical Theory of Communication" defined the bit as the fundamental unit of information and established information theory as a rigorous discipline. The same year, the transistor was invented at Bell Labs by Bardeen, Brattain, and Shockley, eventually replacing vacuum tubes and enabling miniaturisation at scale. ENIAC, completed in 1945, was one of the first general-purpose electronic computers, occupying 1800 square feet and consuming 150 kilowatts of power while performing roughly 5000 additions per second. The ASCII standard was ratified in 1963, assigning 7-bit codes to 128 characters and enabling interoperability between computers from different manufacturers. Through the 1970s, the microprocessor consolidated an entire CPU onto a single chip; Intel's 4004 in 1971 marked the beginning of this trend. The Apple II launched in 1977 and the IBM PC in 1981 brought computing to homes and offices, triggering a mass-market software industry. Tim Berners-Lee proposed the World Wide Web in 1989 and launched the first website in 1991 at CERN, transforming the internet from an academic and military network into a global information infrastructure. Mobile computing accelerated through the 2000s with smartphones integrating powerful processors, wireless networking, and GPS into pocket-sized devices, extending computation into every facet of daily life and cementing TCP/IP as the universal communications fabric.
Frequently Asked Questions
Formula
EV = log2(N^2 / t) where N = f-number, t = shutter speed in seconds
EV is the base-2 logarithm of the ratio of the aperture squared to the shutter speed. Each integer EV step represents a doubling or halving of light. ISO adjustments add log2(ISO/100) to the base EV100 value.
Worked Examples
Example 1: Sunny Day Outdoor Exposure
Problem: Calculate the EV for a sunny day shot at f/8, 1/250s, ISO 100.
Solution: EV100 = log2(f^2 / t)\nEV100 = log2(8^2 / (1/250))\nEV100 = log2(64 * 250)\nEV100 = log2(16000)\nEV100 = 13.97\nApprox illuminance = 2.5 * 2^14 = 40,960 lux
Result: EV = 13.97 at ISO 100, typical of a hazy bright day.
Example 2: Indoor Portrait with Available Light
Problem: A portrait is shot at f/2.8, 1/60s, ISO 800. What is the EV100?
Solution: EV100 = log2(2.8^2 / (1/60))\nEV100 = log2(7.84 * 60)\nEV100 = log2(470.4)\nEV100 = 8.88\nEV at ISO 800 = 8.88 + log2(800/100) = 8.88 + 3 = 11.88\nScene luminance ~ 2^8.88 * 2.5 / pi = 373 cd/m2
Result: EV100 = 8.88 (bright indoors), EV at ISO 800 = 11.88.
Frequently Asked Questions
What is Exposure Value (EV) in photography?
Exposure Value is a number that represents a combination of camera aperture and shutter speed settings that produce the same overall exposure. An EV of 0 corresponds to an aperture of f/1.0 with a 1-second shutter speed at ISO 100. Each increment of 1 EV represents a doubling or halving of the light captured. EV 15 corresponds to bright direct sunlight while EV 5 might represent typical indoor lighting. Photographers use EV to quickly communicate lighting conditions and to determine equivalent exposure settings. The concept was introduced in the 1950s by the German shutter manufacturer Friedrich Deckel to simplify exposure calculations when light meters gave readings in EV units.
How does ISO affect the Exposure Value calculation?
In the standard EV formula, EV is calculated at ISO 100 as the base sensitivity. When you change the ISO, you effectively shift the required EV. Doubling the ISO (e.g., from 100 to 200) adds 1 to the EV, meaning you need one stop less light from the aperture and shutter combination. The ISO-adjusted formula is EV = EV100 + log2(ISO/100). For practical shooting, a higher ISO lets you use faster shutter speeds or smaller apertures in the same lighting. However, higher ISO values introduce more digital noise or film grain, so photographers balance ISO adjustments against image quality. Modern cameras handle high ISO remarkably well, with usable results often up to ISO 6400 or beyond.
Is my data stored or sent to a server?
No. All calculations run entirely in your browser using JavaScript. No data you enter is ever transmitted to any server or stored anywhere. Your inputs remain completely private.
How accurate are the results from Exposure Value EV Calculator?
All calculations use established mathematical formulas and are performed with high-precision arithmetic. Results are accurate to the precision shown. For critical decisions in finance, medicine, or engineering, always verify results with a qualified professional.
What inputs do I need to use Exposure Value EV Calculator accurately?
Each field is labelled with the required unit (metric or imperial). Gather your source values before starting โ for example, a weight measurement in kilograms, a distance in metres, or a dollar amount โ and enter them exactly as measured. The formula section on this page lists every variable and explains what each represents.
How do I verify Exposure Value EV Calculator's result independently?
The Formula section on this page shows the equation used. You can reproduce the calculation manually or in a spreadsheet using those steps. Compare your answer against the worked examples in the Examples section, which use known reference values so you can confirm the calculator is behaving as expected.
References
Reviewed by Daniel Agrici, Founder & Lead Developer ยท Editorial policy