# Thread: How many inches across is copal 0 opening?

1. ## How many inches across is copal 0 opening?

There's a seller on ebay selling a lens board at a steal. I don't think he knows what he's selling as I've asked him what copal it is and he hasn't responded, though he did post a photo of himself measuring the opening which looks to be right at 1.5 inches. Does anyone know copal sizes in inches? If it's #0 then I'm jumping on it, but I want to be sure.

2. ## Re: How many inches across is copal 0 opening?

Look it up here.

Charley

3. ## Re: How many inches across is copal 0 opening?

Copal 0 opening= aprox. 35mm= approx. 1.4 inches.

1.5" sounds right for a Copal 0 shutter, measured roughly.

4. ## Re: How many inches across is copal 0 opening?

Originally Posted by Gem Singer
Copal 0 opening= aprox. 35mm= approx. 1.4 inches.

1.5" sounds right for a Copal 0 shutter, measured roughly.
"Measured roughly" is putting it lightly

5. ## Re: How many inches across is copal 0 opening?

Lens board openings are usually metric, and it's difficult to measure millimeters accurately with a ruler. Even more difficult to measure the diameter of a circular opening.

I/10th of a millimeter is insignificant when it comes to lens board openings. There is plenty of room error.

I'm quite certain that it is a Copal 0 opening. However, if you have doubts, don't purchase the lens board.

7. ## Re: How many inches across is copal 0 opening?

How do you know it is a "steal"? What camera does it fit?

8. ## Re: How many inches across is copal 0 opening?

The correct mounting hole diameter for a Copal #0 shutter is 34.8mm, which is 1.370 inches (mighty close to 1 3/8" which is 1.375").

The hole is larger than the shutter threads because there's a lip on the shutter side of the retaining ring.

This is apparently done to avoid damaging the shutter threads when mounting, by providing extra clearance. (Just speculation on my part.)

- Leigh

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