Roshutsucho: Exposure & ND

How long with an ND filter? How much extra exposure does your film need?
Roshutsucho brings exposure calculations and a timer together for film and digital photography.

FREE TO USE
• ND filter calculator: calculate exposure times for ND2 through ND1000
• Exposure timer: start from a calculated result, pause and resume, and enable a completion alert
• Sunny 16: find aperture and shutter speed combinations for ISO and light conditions
• EV/LV converter: explore the relationship between exposure values and camera settings
• Restore your previous settings for the next shoot

PRO — ONE-TIME PURCHASE
• Integrated calculator: start with a metered exposure or Sunny 16, apply ND compensation, then film reciprocity correction. See each step and the final time
• Named presets: save and recall multiple shooting setups
• Reciprocity correction: estimate longer exposures for the included film stocks
• Push/pull calculations, bellows extension correction and flash guide number calculations

Pro is a one-time purchase, not a subscription. The purchase screen shows the current local price. Purchase restoration is supported.

MADE FOR THE FIELD
A dark interface with English and Japanese support. Calculations, presets and the timer work offline; purchases and restoration require a connection. No ads or account registration. Optional usage sharing is off by default.

Roshutsucho is a calculation tool. It does not measure light with your camera or remotely operate the shutter. Film correction is an estimate: consult film documentation and account for your shooting conditions. The timer supports 1 second to 24 hours. Completion alerts require notification permission; sound may be affected by silent mode, Focus or other device settings.

Support: [email protected]