Which switch for strobes....

[Pfiltz]

Sorry for the newb question. Been a year or so, since I used any type of flash with my 4x5.

There's a sync switch on the lens, labeled M, M, F-X, OFF

Which one should I use to get flash sync? If figure OFF is self explanatory...

MODS, please move this to the LENS forum. Sorry.

[Otto Seaman]

~X~

[Pfiltz]

TY Otto...

[Leigh]

There's a sync switch on the lens, labeled M, M, F-X, OFF

M is for medium-duration flashbulbs. This was the most common type.

X is for electronic strobes.

I presume F-X is a compromise that works with fast-duration flasbulbs and strobes. I've never seen that before.

I don't understand why you have M listed twice.

- Leigh

[Bob Salomon]

M is medium peak flash bulbs, x is for electronic flash, F were for gas filled flash bulbs.

[Jim Jones]

It's always a good idea to check the actual sync with an electronic flash, regardless of the shutter vintage or markings. As electronic flash replaced flashbulbs, the timing in many older shutters was internally modified from F or M to X with no external indication of this. The modification could be quite simple.

[AtlantaTerry]

Set your strobe to a low power.
Set the shutter's synch to "X".
Open the lens to the maximum aperture.
Set the shutter speed to the fastest setting.
Hold up the lens about an arm's length away.
Aim the lens toward the strobe.
Trip the shutter.

You should see a circle of light.
If you see a star then the synch is off because the shutter is either opening or closing when the flash went off.

You should perform this test at least once a year with every shutter. (I do it between Christmas and New Year's Day when there is nothing much else going on.)

[Leigh]

Aim the lens toward the strobe.

Could cause severe eye damage, depending on the strobe power.

Point the strobe at a light-colored wall from several feet away, and point the lens at the same spot.

- Leigh

[AtlantaTerry]

Leigh,

Yes. That is why I said to set the strobe to a low power.

[pasiasty]

And check the bloody switch before each shot, on some shutters it tends to change while you manipulate with time, cocking lever or so. And you won't see anything wrong unless you develop clear sheets.