Now light meters are an interesting subject. It’s best to have only one light meter and get used to its quirks and adjust your technique to get the negatives exposed the way you prefer. But light meters come in various types and styles.
- Reflectance, measures the light reflected from the scene
- Incidence, measures the light falling onto the scene.
- Flash, measures the light from your flash units.
- Spot, measures the area at the end of a 1 to 7 degree cone.
And how they measure the light, what type of sensor they use.
- Selenium cell, powered by the light falling into them.
- Cadmium sulfide, requires an outside source of power
- Silicon Blue Cell light sensitive photodiodes also requiring an outside power source.
Sadly I own three light meters and I haven’t really gotten started.
- The Gossen Pilot we never gave up.
- A Gossen Luna Pro with the spot attachment.
- The Weston Universal, because it has all the numbers.
The Gossen Pilot is a very fine light meter by a great company, does both reflected and incident measurements. The shutter speeds at 1, 1/2, 1/4, 1/15, 1/30, 1/60, 1/125, 1/250, and 1/500. The scale continues on from there and the Gossen Luna Pro uses the same standard. But my Synchro Compur shutter was built in a different time and to a different standard: 1, 1/2, 1/5, 1/10, 1/25, 1/50, 1/100, 1/250 and 1/500 seconds. So there are some mental gymnastics involved is reconciling the light meter and shutter.
Now the Weston Universal is the second model Weston in England produced in 1938 and for one reason or another they used all of the numbers that would fit on the exposure computer.
Arperture Numbers: 4.5, 5, 5.6, 6.3, 7, 8, 9, 10, 11, 12.7, 14, 16, 18, 20, 22, 25, 29, 32.
Shutter Speeds: 1, 4/5, 1/3, 1/2, 2/5, 1/3, 1/4, 1/5, 1/6, 1/8, 1/10 1/12, 1/15, 1/20, 1/25, etc
Like I said, all the numbers making it easier to visualize where to set my aperture, shutter speeds being in fixed increments and on my Compur D arranged to a different standard than the Gossen Pilot.
If you look closely at the circular exposure computer, you’ll see that there are some additional markings.
The A 1/2 and C 2X shows the exposure latitude for color film.
The U and O likewise show the exposure latitude from black and white film.
Try thinking of the A and C as one over and one under exposure, or even Zones IV, V, and VI and the U and O as Zone I and Zone VIII. I am eccentric but I’m not an idiot.
The Gossen LunaPro was an impulse purchase because I really liked my Sekonic Spotmatic as do so many other people. Plus the Luna Pro is what I always thought of as my “night” meter. So much so that I take a reading, lock the needle and use a flashlight to transcribe the reading to the computer.