Sekonic L758D and the Zone System: a quick guide explaining how to measure the contrast range of a scene to determine a Zone System exposure.
I am assuming general knowledge of the Zone System not covered here. There are some excellent references in my Film Resource Kit available to all my subscribers.
For information about how to determine your film speed and work out normal film development times without a densitometer see my post Film speed test Ilford FP4 plus LC-29 developer
- Turn the meter on, and set it to the reflected light mode for 1 degree spot metering
- I am using Shutter Speed Priority display in this example
- Note “plus” and “minus” display along the bottom of display (you may need to set your display type in the custom setting). Note the middle “0” reading represents Zone 5 or middle grey and that the markings are plus and minus one stop deviations from middle grey.
- clear any previous readings using M.CLEAR button, until only the middle indicator is flashing at zero.
Example: (see pics below)
- take a low light reading for Zone 3 (dark grey, just seeing texture) and store in MEMORY
- take another two readings of a general area of interest (middle values) and store in MEMORY
- take a high light reading for Zone 7 (luminous grey, with texture) and store in MEMORY
- There will now be 4 indicator bars equal to the number of readings along the bottom display
- Hold the MID.TONE button down and turn the jog wheel, all indicators will move to the left or right depending on the direction the wheel is turned.
- Turn the jog wheel to place low reading (Zone 3) on the -2 and note how the other indicators fall along the bottom of display, especially the highest value (furtherest to right)
- Keep hold of the MID.TONE and read off the f stop and shutter speed, this is your exposure for your chosen placement.
- If your high value (furtherest to right) exceeds +2 Zone 7, then reduce development accordingly (ie N-1, N-2)
I have used a Pentax digital spot meter for over 30 years and in 2009 had the entire circuitry replaced when the display suddenly stopped working. It is my understanding that Pentax no longer make this meter, so I purchased the Sekonic L758D as a back up. It has multiple functions, but its menu and display are no match for Pentax’s simplicity of use. I currently use both meters.