Exposure Assistant

Matthew Bognar

About this app

This application approximates the length of exposure for various B&W films (and some color films) in low light situations. In low light, extra exposure is needed due to reciprocity failure (also known as the Schwarzschild effect). As such, your camera's meter is not accurate in low light. This application approximates the proper exposure time (based upon manufacturers datasheets). A timer is now included in the application.

The application warns when the user enters an exposure longer than described in manufacturer's datasheets. Although the exposure in these instances is crudely approximated by mathematical extrapolation, it is crucial that users conduct their own exposure tests in these very long exposure situations.

Current supported films:
Adox CHS 25/50/100
Adox CHS 100 II
Adox CMS 20 II
Adox Silvermax 100
Agfa APX 100/400
Bergger Pancro 400
Fomapan 100
Fomapan 200
Fomapan 400
Fuji Acros 100
Fuji Provia 100F
Fuji Velvia 50
Fuji Velvia 100
Fuji Pro 160 NS
Fuji Pro 400H
Fuji Superia 200/400
Ilford Delta 100
Ilford Delta 400
Ilford Delta 3200
Ilford FP4 Plus 125
Ilford HP5 Plus 400
Ilford Ortho Plus 80
Ilford PanF Plus 50
Ilford SFX 200
Ilford XP2 Super 400
Kentmere Pan 100
Kentmere Pan 400
Kodak Ektar 100
Kodak Portra 160/400
Kodak TMAX 100
Kodak TMAX 400
Kodak Tri-X 320/400
Rollei IR 400
Rollei RPX 25
Rollei RPX 100
Rollei RPX 400

Ratings and reviews

Quite probably the most simple, effective and clean app for reciprocity failure calculation. Definitely worth the money. I've had excellent experience with its accuracy for very long exposure times for various films, mostly Portra 160 and Fomapan. It would be very nice if in a future update the ability to add custom formulas for different films was added.

Fab for pinhole. I've always estimated my pinhole shots based on experience...which can be hit or miss. I've ended up with some shots -- that I would have way underestimated times for -- that turned out perfectly thanks to this app (20 minutes instead of my estimate of "about 5-ish..."). Thank you for creating this!

Very useful for long exposure on film, especially with pinhole cameras. Calculations seem to be good, have to use different films to confirm.

What's new

Added Ilford SFX 200. Optional audible alarm added.