Monday, March 4, 2013


The procedure is called "Checking The Galvanometer Adjustment" and is in every Bolex 8mm manual except for:

            Reflex series, P1, 2 & P3, & all Bolex Super 8 cameras

Bolex 8mm "double run" 8mm camera with the letter L or LA in the model designation can be adjusted. This includes Bolex D8l, D8LA, C8L, etc.  If there is no L or LA, such as with B8 model, it means there is no metering system. This procedure is shown in all Bolex 8MM "Double run" printed camera manuals that have a light meter.

Step 1) Carefully pull out the clear plastic dial on the front of the light meter until it engages the chrome center piece. As long as you hold the dial out, the inner dial marker with the black triangle, will engage the inner dial and it can be turned.  While holding the dial out, turn the dial until the inner black triangle lines up with the outer black triangle on the outer dial.

Step 2) Holding the camera as you would for filming, note the relative position of the black meter needle and the red meter pointer. The black needle should be directly behind the red pointer. If it is, the meter is calibrated correctly.

Step 3) If the meter is not calibrated correctly, use a  small screwdriver such as a: Wiha 260 / 1,5 x 40mm screwdriver or equivalent. This screwdriver is available at

I bought mine as a set from the above link. About $27.00 + S&H. You can find the screwdrivers in sets and individually at better hardware stores.

Step 4) Insert the screwdriver tip into the hole located on the top of the meter case near the shutter plate of the left, top side of the meter. Turn screw slowly in either direction until the needle and the indicator are lined up.

Done. If you turn the screw and the needle will not turn anymore, and indicators don't line up, try the other direction. Do not force the adjustment screw when it become "tight". It the meter cannot be adjusted correctly, either the selenium cell or the meter is bad. There are no internal adjustments in these cameras. In this case, both the meter and cell will have to be replaced as a "matched pair" from a donor camera.

All the meters are the same within the same series of cameras. D8L meters will fit a B8L camera as it is the same series. Later series of Bolex D8LA meters will fit C8LA, etc. LA series meters will not fit non-LA cameras. If you have a LA series camera, you will use a LA series camera as a donor. If you have a bad selenium cell or meter (needle), you will need to change BOTH as a matched pair. This is delicate work. New meters are not available. You'll need to buy a donor camera. Be sure the meter works.

Remember, the meter is designed for 25 and 40 ASA. Your will NOT find theses ASA speeds for sale anywhere. Typically you'll find ASA 100, 200 or 400. Maybe B&W film at a higher than 400 ASA. You will need to close the iris or use a neutral filter if the shutter control can't cover the difference in the calculated exposure index.

An external meter such as a Sekonic L-398 is recommended. See blog on metering with Ektachrome here:


  1. These posts are very helpful , thank you. I picked up a Bolex D8L at a garage sale and was having a hard time understanding how the light meter was supposed to work. This is helping.

    Mine seems to respond ok. Then it's all tied to setting the dial to have the ASA match the frames-per-second filming speed , right ? (if you want to get an accurate reading from the meter) .

    BUT if I want to I can just ignore the built in meter and use an external light meter to get a reading and set the lens f-stop manually , correct ? My Bolex D8L came with no prime lenses , but has a Pan Cinor 8 - 40mm zoom lens .

  2. HI there, I have a Bolex P3, I have bought the replacement battery with adapter but I think the exposure meter may be broken, as even testing (as explained in the owners manual) it is not working. Any idea of how can I repair it? Thanks a lot.