Copal shutter firing flash multiple times per exposure

[williaty]

I recently bought a lens in a Copal 3 shutter and tested the shutter as soon as I got it. Sadly, I didn't test the X-sync port. From 1/125th down to 1/15th, the shutter fires the strobe correctly. At 1/8th, sometimes it fires the strobe just once and sometimes it fires it twice. At 1/4er and below, it fires the strobe repeatedly so fast it sounds like it sizzles for the duration of the exposure.

Does anyone recognize this fault? Do you know how serious of a repair it's likely to be?

Thanks for any info you have.

[Tin Can]

I have not seen this, but I almost always shoot flash at 1/30 on Leaf shutters so it's close to my Packard speed. Standardize.

Are trying for an ambient light effect?

Remember 35mm usually synced at 1/60th. Maybe for a good mechanical reason.

Sounds like points bounce.

[williaty]

I was trying to balance the strobes on the model inside against the sunlight in the woods outside the window. The Fujinon SF lens I was working with has a maximum aperture of f/10, so the shutter speed had to fall quite a bit for the ambient exposure.

[Liquid Artist]

I would look at the flash settings first, or at least try it with another shutter.

I do have a Metz flash that does the same thing on one setting, which I assume that it was designed to do.

[LabRat]

The internal flash contacts probably need cleaning... If the speed is slow, the contacts make contact, but if the contacts are intermittent, it may multi-fire as the contacts are not making perfect contact through the cycle...

Many old contacts are oxidized or burnt, but there might be another connector to the flash that also might need cleaning or replacement...

Steve K

[Two23]

I shoot a lot of flash over the past 12 years, mostly with a Nikon DSLR. (I use up to 16 flash, radio triggered.) My thinking is you have a sync cord that is shorted. This is the first place I look when this happens to me. The contacts are a possibility, but I just don't think they would cause flash to over and over. A shorted cord absolutely can and does.


Kent in SD

[williaty]

The strobes and sync cord works fine with every lens and camera except this one.

[Two23]

Somewhere there is a short. Might be in the wires of the switch inside the shutter. The only other possibility I can think of is the contacts somehow become stuck in the closed position.


Kent in SD

[Two23]

I'm home sick today, too sick to go anywhere but not so sick I'm staying in bed. I dug out my Nikon 90mm f4.5 lens in Copal shutter. It's in Copal 0 and not Copal 3, but I'm betting they work the same. I hooked up a Nikon SB-25 to a CyberSync trigger, then hooked up a Cybersync transmitter directly to the shutter. Fired at 1/250s--perfect. Fired at 1/60s--perfect. Fired at 1/30s--perfect. I cut the power from 1/1 to 1/64 as the recycle rate is pretty much instant. Fired flash at 1/15s--perfect, fired at 1/4s--flash fired twice! Set shutter to "B" mode, depressed shutter and held it for 10 seconds. Flash fired multiple times, which was what you were seeing. As long as the shutter is open, the flash seems to be able to fire. At shorter settings the flash does not have enough time to recycle and fire more than once. I've come across this before with other Copal shutters with same result. As long as shutter is open, flash will fire.


Kent in SD

[Neal Chaves]

The flash contacts in all leaf shutters bounce. This was never a problem with older electronic flash units, but with newer ones that store capacitor energy and are ready for the next flash almost instantaneously, you can have multiple pops.