Time
Time-lapse capture planner
Plan photo count, shooting duration and storage from a target clip.
Use tool
Calculators · Free
Bellows exposure compensation
Calculate exposure time from bellows extension and additional filter stops.
01Enter your values
Runs in your browser02Bellows exposure compensation
Runs in your browser
How it works
Calculate exposure time from bellows extension and additional filter stops.
B = (Total bellows extension ÷ Focal length)²; Corrected exposure = Metered exposure × B × 2^(Filter compensation (stops))
Runs in your browser
Discovery source
Your data stays yours
Inputs are processed on this page and are never sent to a server.
About this tool
Use tool ↑Calculate exposure time from bellows extension and additional filter stops.
For large-format product photography: enter focal length and total extension in mm, metered seconds and filter stops. Extension squared divided by focal length squared is the bellows factor. Multiply time by this and by two to the filter-stop power. For conventional lenses with a calibrated measurement; excludes telephoto optics and film reciprocity failure.
How to use it
- Enter your values
Focal length · Total bellows extension · Metered exposure · Filter compensation (stops)
- Calculate / generate
Calculate exposure time from bellows extension and additional filter stops.
- Result
2 s
Calculation method
B = (Total bellows extension ÷ Focal length)²; Corrected exposure = Metered exposure × B × 2^(Filter compensation (stops))
Bellows exposure compensation
- Focal length
- 150 mm
- Total bellows extension
- 300 mm
- Metered exposure
- 0.25 s
- Filter compensation (stops)
- 1
Result
2 s
Frequently asked questions
Should I apply this after through-the-lens metering?
No, not if the meter already includes bellows or filter loss. Avoid counting the same correction twice.
Where does my data go?
Calculations run on your device. Form inputs are not sent to a server.