Flash Advice Needed for "X-Sync" Lenses

[rguinter]

Good golly!

I'm one who has done 20+ years of outdoor hobby photography without even a thought of using flash. Never owned one.

But now my religion is changing and I find myself wanting to use fill-flash with certain subjects... especially back-lit subjects with infrared film.

To keep (somewhat) in tune with my old-fashioned (geezerly) ways I would love to use flashbulbs... but that is a problem because all my MF/LF camera lenses are "X-Sync." And I doubt their contacts could withstand the high current short-circuit needed to fire the old bulbs.

So to my question: does anyone have a recommendation for a modern X-Sync flash unit that could fill my needs? Would have to fit a hot-shoe for my MF cameras and be externally mountable for LF.

Or maybe someone has a suggestion how to fire up the old bulbs with X-Sync flash circuits? I was quite handy with a schematic and soldering iron some years ago.

I'm open to any suggestions... and any and all are welcome.

Cheers.

Bob G.

[Brian C. Miller]

Hate to break it to you, but X-sync means that the flash only fires when the shutter is completely open. It isn't a question of firing off the bulbs, it's a question of when the flash timing happens.

[Gem Singer]

A Vivitar 285HV is a nice shoe-mount flash.

Can be adapted to LF cameras by means of a mounting bracket, or mounted on a light stand and umbrella.

Versatile, inexpensive, and easily available (both new and used).

Operates off of four penlight cells, or an A.C. adapter.

Guide Number of 120 is sufficient for fill flash use.

[Jim Jones]

The X-sync contacts close just as the shutter reaches its fully open position. If this is used to trigger flashbulbs, and the shutter remains open long enough, you will get normal flash exposure. Flashbulbs produce most of their light within 40 milliseconds, or maybe 20 ms for smaller bulbs, after the contacts close. Therefore, shutter speeds of 1/15 or sometimes 1/30 second should work. Using electronic flash with shutters synced for flash bulbs is a problem. The flash will fire before the shutter opens.

On older shutters the same contacts were used for both strobes and flashbulbs. They should handle the current. Some electronic flashes had a high surge current, too. There may be problems with some newer flashes, especially if they use an electronic circuit instead of mechanical contacts.

[Mark Woods]

I think you'll have a problem getting the flash bulbs. In Hollywood some of them sell for upwards of $5 each since they aren't manufactured any more.

[rguinter]

Hate to break it to you, but X-sync means that the flash only fires when the shutter is completely open. It isn't a question of firing off the bulbs, it's a question of when the flash timing happens.

Yes Brian I know about the M-, F-, and X-sync timing and how soon prior to shutter opening they occur. With M- occurring about 20-25 milliseconds early, F- a little later but still early with respect to shutter timing, and so forth.

I understand the X- actually stands for Xenon when it was first established to fire Xenon flash tubes at precisely the moment when the shutter was open. Xenon requires extremely high voltage and very low current.

But as a result, the X-sync contacts are also designed to handle much lower current and therein would be quite a large problem for using flashbulbs with X-Sync circuits... even given that the flash peak would likely occur too late to do the most good for lighting purposes.

As I stated in the opening post... I would love to use flashbulbs because I'm old fashioned and tend to reject new technology... but I probably can't.

But anyway still looking for a reasonable solution to add some frontal infrared energy to back lit subjects in daylight.

Cheers. Bob G.

[rguinter]

I think you'll have a problem getting the flash bulbs. In Hollywood some of them sell for upwards of $5 each since they aren't manufactured any more.

Actually I have quite a bunch of them. Would like to use them for my purposes if I can. But alas... probably can't.

Cheers. Bob G.

[Robert Perrin]

Your "x" sync shutters can be sync'd for bulbs with a solenoid. Most, if not all, are adjustable for accurate synchronization. And in my opinion it's the best means for tripping a LF shutter whether with flash bulbs, electronic flash or ambient light. A google search should turn up sources for bulbs. Here's one example: http://www.meggaflash.com/

[rguinter]

The X-sync contacts close just as the shutter reaches its fully open position. If this is used to trigger flashbulbs, and the shutter remains open long enough, you will get normal flash exposure. Flashbulbs produce most of their light within 40 milliseconds, or maybe 20 ms for smaller bulbs, after the contacts close. Therefore, shutter speeds of 1/15 or sometimes 1/30 second should work. Using electronic flash with shutters synced for flash bulbs is a problem. The flash will fire before the shutter opens.

On older shutters the same contacts were used for both strobes and flashbulbs. They should handle the current. Some electronic flashes had a high surge current, too. There may be problems with some newer flashes, especially if they use an electronic circuit instead of mechanical contacts.

I do have a couple of older shutters with vintage lenses... but unfortunately I rarely use them and they are not the ones I want to use for this project.

Although one of the Ilex shutters actually has a sync setting switch that allows one to preset either 20-, 5-, or 0-millisecond advances for flash timing. But my guess that, given its age, unless the flash contacts were gold-plated, they are probably corroded and unusable.

Bob G.

[rguinter]

P.S. For the sake of clarifying my original post, and for those that think timing may be a serious issue, it probably really isn't. My real purpose for wanting to use fill flash is to fill in some infrared light on back-lit subjects with infrared film.

And my normal exposure time for these subjects is 1 - 4 seconds.

So I really don't care if the flashbulb takes an extra 25-50 milliseconds to really burn. The shutter will be open during and after this time.

Bob G.