Photography Calculators
These calculators answer the questions photographers usually work out on the back of a hand: how much will be sharp at f/2.8, where to focus so a landscape is sharp to the horizon, what shutter speed matches f/8 at 1/125 after opening up, how long to expose behind a 10-stop filter, how many seconds the stars allow before they trail, and how wide a lens sees on a given sensor.
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All Photography (5)
Depth of Field Calculator
Near and far focus limits, hyperfocal distance and circle of confusionExposure Calculator
Exposure value and equivalent aperture, shutter and ISO settingsND Filter Calculator
Shutter speed with an ND filter from stops or ND numberStar Trail (NPF & 500 Rule) Calculator
Longest shutter before stars trail, by NPF and 500 ruleField of View Calculator
Angle and width of view from focal length, sensor and crop factor
Which tool do I need?
Get a landscape sharp from front to back
Find the hyperfocal distance for your lens and aperture and the nearest point that stays sharp.
Change aperture or ISO and keep the exposure
Enter the metered settings and solve for the new shutter speed, aperture or ISO.
Work out a long exposure behind a dark filter
Turn the metered shutter speed into the time behind an ND1000 or stacked filters, with a timer.
Shoot the Milky Way without star trails
Get the longest untracked shutter speed for your camera and lens by the NPF and 500 rules.
Choose a lens that frames the scene
See the angle of view and the width covered at a distance, or the focal length for a given width.
About Photography
Each one uses the standard published formula and shows it with your numbers substituted: the thin-lens depth of field equations, EV = log₂(N²/t), filter factors as powers of two, the simplified NPF rule credited to Frédéric Michaud with the sidereal rate of the sky, and 2·atan(d/2f) for angle of view. Sensor presets run from 1/2.3-inch compacts through APS-C and full frame to 645 medium format, and every input can be overridden.
All calculations run in your browser and the settings sit in the page address, so you can bookmark a lens setup or send it to someone. Results are planning figures: lenses, filters and viewing sizes vary, so check the first frame on location.
Guides
- Depth of Field and Hyperfocal Distance, Worked OutWhat sets the near and far limits of sharpness, where the circle of confusion comes from, why sensor size changes depth of field, and how to use the hyperfocal distance for landscapes.
- Exposure Value Explained: Stops, Sunny 16 and Equivalent ExposuresHow aperture, shutter speed and ISO trade against each other in stops, what an EV number means, the scene brightness table behind sunny 16, and how to find an equivalent exposure quickly.
- ND Filters for Long Exposure: Stops, ND Numbers and DensityReading ND1000, 3.0 and 10-stop on a filter, working out the new shutter speed, stacking filters, choosing the strength for water, clouds and video, and correcting for film reciprocity.
- NPF Rule vs 500 Rule: Sharp Stars Without a TrackerWhy stars trail, how fast they cross a sensor, why the 500 rule fails on high-resolution cameras, the NPF rule with pixel pitch and aperture, and how declination buys extra seconds.
Frequently asked questions
Do the photography calculators work for crop-sensor cameras?
Yes. Pick APS-C, Micro Four Thirds, 1-inch or another preset, or enter a custom sensor size, and enter the real focal length printed on the lens. The tools apply the crop factor where the formula needs it.
Which formulas do these photography tools use?
Standard published ones: thin-lens depth of field and hyperfocal distance, EV = log₂(N²/t) with ISO scaling, ND factor = 2 to the power of stops, the simplified NPF rule t = (35N + 30p)/f and angle of view = 2·atan(sensor/2f). Each tool shows its formula with your numbers.
Are the results exact for my lens?
They are as exact as the models allow. Real lenses differ slightly from thin-lens behaviour, filters vary from their nominal strength and acceptable sharpness depends on how large the image is viewed, so treat results as a strong starting point and check on location.
Can I use these calculators on my phone in the field?
Yes. They work at phone widths, need no sign-in and keep the settings in the address bar, so you can bookmark your usual camera and lens before you go out.
Why do two calculators give different times for night sky photos?
The 500 rule was made for film and small prints and allows a star to drift several pixels on modern sensors. The NPF rule uses your pixel size and aperture and gives shorter, sharper times. The star trail calculator shows both.