Free Online Photography & Music Tools

These free photography calculators and free music theory tools online run the numbers on a shoot or a song without you leaving your browser tab. Set hyperfocal distance, plan a star exposure, transpose a chart into the singer's key. Nothing is uploaded and nothing is sent to us.

Working out the shot

The most common question here is how you calculate shutter speed with an ND filter, and the ND Filter Calculator works out how long an exposure runs behind a 10 stop filter. The Depth of Field Calculator sets hyperfocal distance, the Print Size and DPI Calculator checks whether a 24 megapixel file holds up at 300 DPI, the Crop Factor Calculator translates a full frame focal length, and the Time-Lapse Interval Calculator and 500 Rule Calculator plan frame counts and star exposures.

Answers mid rehearsal

Mid rehearsal the Chord Finder, Scale Generator and the interactive Circle of Fifths answer the questions that come up on the spot, the Chord Chart Transposer moves a whole chart into the singer's key, and the Delay and Reverb Time Calculator gives millisecond values for the tempo you are actually playing. The Capo Position Calculator, Note Frequency Chart, Chord Progression Generator and Interval Ear Trainer fill in the rest, whether you are writing, tuning or training your ear.

Nothing leaves your phone

Every calculation happens right on your own phone or computer, so nothing here is sent to us. No photo or audio file is uploaded, there is no sign up and no account to create, and nothing tracks you. That matters most where the signal is worst, which is often exactly where you need the numbers: a dark hillside with the 500 Rule Calculator open, or a studio with one bar of signal and the Note Frequency Chart on screen.

Frequently asked questions

How do you calculate shutter speed with an ND filter?

Multiply your unfiltered shutter speed by 2 raised to the number of stops the filter blocks. A 10 stop ND turns 1/4 second into 1/4 times 1024, roughly 256 seconds, which you round to about 4 minutes on bulb. A 6 stop ND turns 1/60 into close to 1 second. Meter without the filter, fit it, then dial in the result the ND Filter Calculator gives you.

What is the 500 rule and how long can I expose before stars trail?

The 500 rule estimates the longest exposure before stars blur into trails: divide 500 by your effective focal length in millimetres. At 20mm on full frame that is 25 seconds. On an APS-C body multiply the focal length by the crop factor first, so 20mm behaves like 30mm and allows about 16 seconds. It is a starting point, and high resolution sensors often want 300 divided by focal length instead.

How do I work out delay and reverb times in milliseconds for a tempo?

Divide 60000 by the tempo in BPM to get the length of a quarter note in milliseconds. At 120 BPM a quarter note is 500ms, an eighth is 250ms, and a dotted eighth is 375ms, the classic rhythmic delay setting. Reverb decay is usually set near one bar, so roughly 2000ms at 120 BPM in 4/4. The Delay and Reverb Time Calculator prints the whole table at once, free and with no sign up.

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