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AG-1 Flashbulb History

Anthony Oresteen , Jun 15, 2005; 08:27 a.m.

Last weekend I had a lot of fun using my Minolta MG 16mm camera with the AG-1 flash. I got a lot of strange looks using flash bulbs!

I can't find much on the AG-1 bulb other than it was intoduced in 1958.

What does 'AG' stand for? Who invented it? I am just curious!



Walter Degroot , Jun 15, 2005; 09:16 a.m.

they were handy amall ans easy to carry. I had "cube adapters" that took 4 ag1 bubs and a canon flash - looked like a small ef that took 5 ag1 and fired them in sequence also a very small unit that was ideal for a sub-min camera

Donald Qualls , Jun 15, 2005; 09:58 a.m.

I'm pretty sure AG stood for "all glass" -- as opposed to prior bulb series that all had metal bases. Eliminating both the base and the multiple manufacturing steps to attach it, electrically and mechanically, to the glass envelope cut the cost of these bulbs substantially compared to the larger M series. There was also an AG-3, which had about the same light output as an M3, but AG-1 was the baseless standard, since by then most photographers were using faster film and didn't need the greater light output of the larger bulbs. As a bonus, the AG-1 (along with the M2) had a faster ignition time (less delay between shutter contact and peak output), and could be used with X synch below 1/30 -- where most bulbs required 1/15 on X synch in order to keep the shutter open long enough for the bulb to ignite and burn -- which in turn contributed to the demise of M synch or dual-synch shutters.

Even an AG-1, in a good sized reflector, is far more light than is needed with ISO 400 film; it becomes difficult to get close to the subject because you can't stop down enough. It *is* possible to use shorter shutter speeds with M synch leaf shutters, but it's hard to be certain what you'll get for exposure because the light output of the bulb isn't constant; rather, it builds to a peak and then decays back to darkness over about 1/25 second; M synch has a 15-20 ms delay to allow ignition, but a shutter shorter than 1/60 won't even catch the peak, and the exposure becomes less by a larger margin than the shutter speeds would suggest.

I couldn't swear to it, but I think Sylvania is responsible for the AG-1 (of course, by 1959 or 1960, every maker of flashbulbs was producing AG-1, and most camera makers had at least one flash unit or camera that used it -- cheap always sells). They surely accounted for the lion's share of sales; even now, some 25 years after the last AG-1s came off the lines, most of the bulbs we see are Sylvania Blue Dot.

Phillips had another baseless format that they seem to have sold only in Europe, identical to the midget or bayonet series bulbs but with only a metal ring, and an adapter to mount the bulbs in the older style flash units, but they don't seem to have sold well, probably due to being more expensive, too big for then-current films, and second to the market. The "M" series bulbs, with the small metal base retained on an indented ring, were "Miniature" bulbs, and the bayonet base (5, 6, 11, P25) were called "midget" when they came out -- by comparison with the immense (by today's standards) screw-base type -- and were the last/smallest format to include focal plane type bulbs (the 6 and 11), with a long enough flat output peak to accomodate the travel of a 1/60 X-synch FP shutter.

There's a lot of good information, including time/output curves, at www.flashbulbs.com.

Kelly Flanigan , Jun 15, 2005; 10:18 a.m.

I think the AG-1 came outabout the time of the minature UHF acorn valves/tubes developed for project mercury; with no base; short leads for UHF performance.

Ceri Evans , Jun 15, 2005; 05:12 p.m.

The capless PF series seem to have been pretty much the standard here in the UK from the late-fifties onwards, and have survived in large numbers (they were made by several manufacturers, not just Phillps - a quick look through my bulb box shows Atlas, Mazda and Wotan bulbs of the type). By comparison AG bulbs are fairly rare here.

The PF had a big advantage over the AG bulbs, the 'B' versions for use with colour film was exactly the same power as the ordinary version, unlike the AG1B which I think was a stop slower than the AG1.

I love using flash bulbs though 15v and 22.5v batteries are a bit pricey... take a flashgun to a party and everypne wants their picture taken with it!

Donald Qualls , Jun 15, 2005; 08:14 p.m.

The standard in America has always been for the blue bulbs to be identical to the clear, except for the blue filter coating. That makes them cheaper, since anything manufactured is cheaper if you make a million all alike and modify half than if you make half a million each of slightly different versions. And yes, there is a little loss of light, but it's more like a half stop than one stop.

Used to be, you'd use clear bulbs for B&W and blue for color, and since the films were different speeds, you needed a different guide number anyway, so it was no big deal. Now, common color films are the same speed as common B&W, so we notice the difference in the bulbs a lot more.

Jeff Polaski , Jun 16, 2005; 07:44 a.m.

An old Minox 8x11 trick, using the BC flash with an AG-1 bulb, was to hold one layer of your handkerchief over the flash to reduce the light about one stop. Two thicknesses: two stops. The AG-1B (blue) could be counted for about one stop less than the clear AG-1.

Yes, just about all of us carried handkerchiefs in this days. Never knew when a lovely woman might swoon.

Donald Qualls , Jun 16, 2005; 08:17 a.m.

That handkerchief trick survived well into the xenon flash era, right up until the thyristor automatic flashes made it obsolete. Even though few carry a hanky now, it works the same with a single layer (one ply) of "facial tissue" whether it comes in a box or on a roll.

Of course, I'm now using a tiltable flash for most of my bulb work, so I can count the path to the ceiling and back (might give 11 feet instead of the four from lens to subject) and take off anywhere from 1/3 to 1 stop for the ceiling reflectivity as well (and I can also mix the soft bounce light with a little direct, bare-bulb type light using an intermediate tilt, or fold up the reflector for true bare-bulb). Not to mention I can use any bulb from AG-1 up to the bayonet Press 25 (though I only have AG-1, M2, and M3 on hand). And no red-eye from bounce flash, of course...

Anthony Oresteen , Jun 16, 2005; 05:12 p.m.

FWIW Radio Shack carres 15 volt & 22.5 volt batteries for BC guns.

23-9008 is the 504 15v battery

23-9023 is the 412 22.5v battery. Both cost $6.99

Stephen L. Passman , Feb 01, 2007; 01:44 p.m.

I was a high school student in 1958. I recall switching from #5 GE bulbs to AG-1 because they were cheaper. My recollection is that the first ones available were European, probably Philips. Philips also made an adaptor so that he AG-1 could be used in the same socket as #5 bulbs. I recall also being impressed by the environmental responsibility: for AG-1, you disposed of only the bulb; for #5, you threw away a metal base also.

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