For those of you amateur photographers out there who like shooting film, sometimes old cameras don't have the right light meter for getting the correct exposure. Sometimes they are faulty, inaccurate or have no light meter at all! Photographic light meters can be pretty expensive but analog foot-candle meters are cheap because they don't really have any photography purpose, until now. Tthis guide will show you how to put it to work for photography.
Foot-candles are a unit of light that can be directly correlated to Exposure Values (EV) which are a list of simplified amounts of light and are often referenced to possible scenarios which you might find this amount of light in. Paper exposure calculators work on the principle of manually identifying an exposure value based on the description and then aligning the EV scale with your film sensitivity to deduce shutter speed/aperture combinations for your camera.
FC and EV are directly related, so modifying the meter back-panel is all that is required to turn a FC meter into an EV meter, and it works great. It takes all the guesswork out of using a paper exposure calculator which is great for beginners.
Step 1: The Meter
The FC meter I used was a General Electric Type 214 foot-candle meter, it has 3 ranges controlled by a switch on the right side, and a plastic-covered selenium cell on top. There is also a small metal grate that can be placed over the cell to drop its sensitivity by 10x so that full daylight can be metered as well.
Step 2: Getting Started
Step 3: Making a New Scale
Use your favorite drawing software to make a new scale, drawing on top of the old one. I recommend using a program that allows layering images so the old scale and new scale pictures don't become mangled together.
If you happen to have found the same light meter as me (GE 214) you can print out the attached PDF and use my template, it is correctly scaled for printing on 8.5x11 paper.
Step 4: Insert and Reassemble
Step 5: Using the Meter
Steps to take a measurement
- Place or hold the meter in the same lighting as the subject
- Read the EV value off the meter
- Slide the Exposure Calculator so the ISO film speed of your film points to the EV value you read
- Read the Aperture/Shutter Speed values off the bottom of the Exposure Calculator
- Set your camera to these values