Exposure Calculator

The Exposure Calculator is a powerful tool for photographers of all skill levels who want to master the art of controlling light in their images. At the heart of photography lies the concept of exposure — the amount of light that reaches your camera sensor or film during a shot. Too much light produces an overexposed, washed-out image; too little creates an underexposed, dark result. Achieving the perfect exposure requires balancing three interdependent camera settings known as the exposure triangle: aperture, shutter speed, and ISO sensitivity. Aperture refers to the size of the opening in your lens through which light passes. It is expressed as an f-stop number such as f/1.4, f/2.8, f/8, or f/16. A lower f-stop number means a wider opening and more light entering the camera, while a higher f-stop means a smaller opening and less light. Aperture also controls depth of field — wide apertures produce a shallow depth of field with a blurred background, ideal for portraits, while narrow apertures give a deep depth of field with everything in sharp focus, perfect for landscapes. Shutter speed determines how long the sensor is exposed to light. Fast shutter speeds (e.g., 1/1000s) freeze motion and reduce the risk of camera shake. Slow shutter speeds (e.g., 1/15s or longer) allow more light in and can create motion blur effects for flowing water or light trails. Shutter speed and aperture work together reciprocally: doubling the shutter speed halves the exposure, while opening the aperture one stop doubles it. ISO sensitivity measures how responsive your sensor is to light. Low ISO values (100–200) produce clean, low-noise images and are best used in bright conditions. Higher ISO values (800–3200 or more) allow shooting in dim environments but introduce digital noise or grain into the image. Modern cameras handle high ISO remarkably well, but minimizing noise is still a consideration. The Exposure Value (EV) is a standardized number that combines these three settings into a single measure of light. For a given ISO 100 baseline, EV = log₂(N²/t) where N is the aperture f-stop and t is the shutter speed in seconds. This calculator extends the formula to include your actual ISO and any exposure compensation you apply, giving you the true scene EV. EV values typically range from about −6 (extremely dark) to 20 (direct sunlight on snow). By understanding EV, photographers can quickly translate lighting conditions into appropriate camera settings and maintain consistent results across different scenes.