BetterPhoto Q&A
Category: Traditional Film Photography

Sekonic L-VI Exposure Meter

The photo cell has a mask/shutter, and the frame of the unit says "open" near blue marks and "closed" near red marks. (Okay so far, but those marks are the only red and blue colors I see.)

The meter face has markings that look like f/stops, going from 0 through 8.

There are several concentric sets of numbers. The outermost is f/stops, from 1 through 32. Then there comes a shutter speed set of numbers, running from 4 sec. through 1/1000 sec. There is also an ASA index (which also makes sense). However, there is a "Light Value" window, which runs from 3 through 19.

I suppose my question is how do I relate the meter scale (0 through 8) to this Light Value (3 through 19), knowing full well that something's supposed to be red and something's supposed to be blue????

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November 30, 2006

Old fart's know this meter.

The Sekonic L-VI is typical of meters available in the fifties. The meter is self powered, meaning the photo cell generates electricity and the meter movement is actually a volt meter. As light falls on the cell, the meter needle is caused to move towards the right. The numbers on the scale are incremented in f/numbers. The scale starts at one (f/1) and proceeds to eight (f/8). Each f stop is a doubling or halving of light energy.. The full f/stops (those that follow the convention of double and half are 1 – 1.4 – 2 - 2.8 – 4 – 5.6 – 8. Note the scale on the meter face has wider (bold) marks for each full f/stop the ½ f/stops are indicated by a thin mark. ½ stops and 1/3 stops were used on many cameras particularly large format cameras. As the needle moves right it is receiving more light. The amount of light energy to cause the needle to move right is non linear. Stated another way as the light level increases the amount of electricity generated becomes greater, to compensate the meter scale uses wider spacing between values going to the right. Note the space between 1.4 and 2 as compared to 5.6 and 8, both are 2x light energy changes.

In dim light the meter would not see enough light to cause the meter needle to move. The maker installed an aperture a hinged door in the front. In dim light the door is opened thus allowing more light to reach the meter. Note two indexes are marked on the meter face. Blue is “open” for dim light operation, red is “closed” for bright conditions. I think the scale behind the needle also changes with the door position.

To operate:
Set the ASA (now ISO) value to the film speed or digital speed setting you are using.
In bright light the front door will be closed and the “Red” mark is the index point. In dim light the front door is open and “Blue” mark is the index point
Aim the meter at an outdoor vista in sunlight – door is closed. Angle the meter slightly down, so the sky has reduced influence. Note where the needle falls; note the number under the needle. The dial is a circular slide rule. It is not interconnected to the needle. Rotate the dial until the number engraved on the outer silver ring of the circular slide rule is aligned and centered between the two marks in “Red”. (with door open you would align and center between the two “Blue” marks.

Now the circular slide rule dial indicates all the shutter speeds and f/numbers that are applicable. Select the desired f/number outer silver dial; note the correct shutter speed is directly across on the black dial. Don’t like that combination? Select any other pair (those on silver adjacent to those on black) without moving the slide rule Again, each appropriate shutter speed is directly opposite the appropriate f/number.

In red on the dial are frame speeds. These were/are used in Cine cameras. The typical 8mm home movie camera operated at 16 frames per second. These replace shutter speeds on Cine cameras.

Some cameras used EV (Exposure Value) notation. Maybe I will discuss this next time.

Best regards,
Alan Marcus
ammarcus@earthlink.net

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December 01, 2006

Thank you very much for the explanations and the instruction. The meter works great!

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December 01, 2006