Photography Calculators Every Photographer Should Know

Nobody learns everything at once. You start taking photos, discover what works, run into something you don't understand, look it up, forget it again, look it up again. That's fine. That's how learning works. But there are a few topics in photography that come up for almost everyone. Things you once looked up, never quite remembered, and where you just want a quick tool without having to watch a twenty-minute YouTube video. Here they are. What does crop factor actually do to my lens? You buy a 50mm lens for your APS-C sensor camera. Someone tells you it behaves like a 75mm. You sort of understand why, but the exact number? You end up calculating it again every time. The Crop Factor calculator does that for you. Enter your focal length and sensor size and you instantly see the full-frame equivalent. Useful when comparing lenses, or when figuring out what a new lens will do on your body. Depth of field: how much is actually in focus? You shoot a portrait at f/1.8. The eyes are sharp, but the ears already aren't. Or you're photographing a group and you wonder: is f/5.6 enough to get everyone in focus? Depth of field starts to feel intuitive after a while, but the exact calculation isn't something you do in your head. The Depth of Field calculator shows you how much is in focus in front of and behind your focus distance, based on your camera, lens and aperture. Worth clicking through once if you want to better understand what happens at your smallest aperture values. Aperture, shutter speed, ISO: what does what? The exposure triangle is the foundation of photography. Everyone has read something about it at some point. But actually seeing what happens when you adjust one of the three? That's a different story. The Exposure Triangle tool is interactive. You adjust one value and immediately see what that means for the other two and for your overall exposure. Visual, fast, and much clearer than a written explanation. Useful for beginners. But also as a refresher when you're not quite sure what ISO does relative to your shutter speed. Which focal length suits what I want to shoot? 35mm for street photography. 85mm for portraits. 200mm for sports. That's how it's usually taught, but what does a 35mm actually look like on a full-frame camera? And what if I use that lens on a crop sensor? The Focal Length simulator shows you how a given focal length frames a scene. You pick the focal length and sensor format and immediately see the difference in field of view. Handy when you're unsure about a new lens, or when you want to understand why a colleague with a different camera makes different choices. When do you use which light modifier? Softbox, octabox, beauty dish, reflector, ring flash. There are plenty of options. And if you don't work with studio lighting every day, it's not always obvious which one to reach for. The Light Modifiers tool explains it clearly. Which modifier produces which kind of light, and in which situation does it work best? Not a technical product page, but an overview from a photography perspective. Worth scrolling through when you're preparing for a studio day or considering a new modifier. How much power does my flash need at this distance? When working with an external flash, there's a calculation that tells you how much power you need at a given distance. The guide number. Most photographers know it exists, but rarely do the math. The Flash Guide Number calculator does it for you. Enter distance, aperture and ISO, and get the flash power out. Or the other way around. Saves testing and saves blown-out backgrounds. A term you don't know? Just look it up. Photography has its own vocabulary. Bokeh, hyperfocal distance, bracketing, clipping, the halo effect. Some terms you know inside out, others you hear occasionally but aren't quite sure what they mean. The Photo Thesaurus is a photography dictionary that explains terms the way you actually use them. Not as an encyclopedia, but as a practical reference. Not the flashiest tool on the platform, but one of the most used. Just knowing things is a skill too Getting better at photography isn't only about practice. It's also about understanding things at the moment you need them. And sometimes that's just a quick calculation, a visual comparison or a term you want to check. All the tools above are free at apps.michielheijmans.com. No account, no subscription, just use them.