Exposure value and trades, depth of field, field of view, crop factor, ND filters, handheld and star-trail rules, print size, sunny 16, flash and time-lapse.
payments ON MAINNET (real money) · 11 live endpoints
| Endpoint | Price | What it answers |
|---|---|---|
GET /crop-factor | $0.02 | Crop factor of a sensor, with the full-frame equivalent focal length, aperture and ISO for a lens, or a custom sensor size. |
GET /depth-of-field | $0.02 | Depth of field from focal length, aperture, distance and sensor: near and far limits, total depth and hyperfocal distance. |
GET /exposure-trade | $0.02 | Hold exposure constant: change one setting (aperture, shutter or ISO) and get the other two compensations, in stops. |
GET /exposure-value | $0.02 | Exposure value (EV) from aperture, shutter speed and ISO, the light level it suits, and equivalent aperture and shutter pairs. |
GET /field-of-view | $0.02 | Horizontal, vertical and diagonal angle of view for a lens and sensor, and the width and height of scene covered at a distance. |
GET /flash-guide-number | $0.02 | Flash guide-number maths: range for an aperture and ISO, or the aperture needed for a distance, in metres and feet. |
GET /nd-filter | $0.02 | ND filter maths: convert between ND factor, stops and optical density, and get the new shutter time with the filter on. |
GET /print-size | $0.02 | Print size from image pixels at a DPI, or the pixels and megapixels needed for a print size; with viewing-distance advice. |
GET /shutter-rule | $0.02 | Minimum handheld shutter speed (reciprocal rule) and the longest star-point exposure by the 500 rule and the NPF rule. |
GET /sunny-16 | $0.02 | The sunny-16 rule: starting aperture and shutter speed for sun, cloud or shade at your ISO, with the exposure value it implies. |
GET /timelapse-calc | $0.02 | Time-lapse planner: give any two of interval, shooting time and clip length to get the rest, frame count and storage. |
GET /catalog returns this list as JSON. Activity hub · uptime.
Results are computed locally from standard optics and exposure formulas, provided as is, for ideal lenses and thin-lens approximations. Real lenses vary (focal length changes when focusing, diffraction, distortion) and depth-of-field depends on viewing assumptions. Treat results as planning aids, not guarantees. Every paid response carries a disclaimer field.