Bellows extension and reciprocity correction for large format

Fields keep your last setting until this tab is closed.

01Film

Film stock Meter ISO

Choosing a film selects its box speed. Set your meter to the ISO shown here.

02Lens and extension

Focal length Lens board to ground glass (mm)

03Meter reading

Aperture (marked) Metered time

04Filter (optional)

Filter factor

05Result

Bellows factor

Effective aperture

Corrected time, before reciprocity

Reciprocity added

Expose for