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Randy Moe
1-May-2015, 16:57
As I understand it open bulb flash means one opens the shutter on bulb, time or for as long as we want in a dark photography arena.

Thus the shutter is open and we trigger the flash manually at that time.

This can be flashbulbs, studio flash, Speedlights or lightning I suppose.

The reason I bring this up, is I just got what appears to me, an open bulb flashbulb holder. It has no wired or wireless connection. It's labelled REXO Burke & James, and is nicely made of aluminum. It seems to hold 2 C batteries, but I would think in it's era a higher voltage battery would be used.
In the pics, it has a medium base flash bulb the size of a common light bulb mounted. No batteries yet. It has a small test bulb on top, which as I write this must be only a normal flashlight bulb of 3 to 5 volts.

The reflector is 11" in diameter. I could not resist, it was $15...

Does anybody know anything about this? Have you used one?

I will get batteries next week at Costco.

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mdarnton
1-May-2015, 17:01
Don't know that flash but the little dome on the top could be a sensor to use it as a remote?

Randy Moe
1-May-2015, 17:18
Don't know that flash but the little dome on the top could be a sensor to use it as a remote?

Maybe, but this thing seems simpler than that. I tried optical slave trigger the other day and no go with a different rig.

I need batteries to test it. And I will wait for the buy a dozen deal at Costco.

Jim Jones
1-May-2015, 19:41
Two 1.5 Volt batteries are sufficient to ignite a flash bulb. Many flashes back then used two or three batteries as small as AA size.

Jac@stafford.net
1-May-2015, 20:57
Does anybody know anything about this? Have you used one?

Yup. The very big reflectors were not popular largely because they interfered with the photographer's head, as you can imagine.

I have one particularly thorough volume on bulb flash photography published in the 40's I wish I could copy it for you.

Google Books, perhaps? I will look into this!


Jim Jones: Two 1.5 Volt batteries are sufficient to ignite a flash bulb. Many flashes back then used two or three batteries as small as AA size.

True. And no surprise that around WWII we could get big bulb flashes that used NO batteries at all, largely made in the USA and Britain. I've posted pictures of some.

Here is an unusual, possibly rare version (http://www.digoliardi.net/leica-flashtronic.jpg)bracketed for a Leica. I have one! I have a couple more different universal versions I could post as well.

.

Randy Moe
1-May-2015, 21:31
Yup. The very big reflectors were not popular largely because they interfered with the photographer's head, as you can imagine.

I have one particularly thorough volume on bulb flash photography published in the 40's I wish I could copy it for you.

Google Books, perhaps? I will look into this!



True. And no surprise that around WWII we could get big bulb flashes that used NO batteries at all, largely made in the USA and Britain. I've posted pictures of some.

Here is an unusual, possibly rare version (http://www.digoliardi.net/leica-flashtronic.jpg)bracketed for a Leica. I have one! I have a couple more different universal versions I could post as well.

.

Magneto I suppose. Costly initially but would work for a long time.

Jim Jones
2-May-2015, 06:22
Magneto I suppose. Costly initially but would work for a long time.

More likely mechanically ignited. A sharp blow on some crystals produces a spark.

Jac@stafford.net
2-May-2015, 07:40
Magneto I suppose. Costly initially but would work for a long time.

Exactly, a magneto ignites the bulb. The front button releases the spring driven rotor which has a cam inside which pushes the shutter or cable release. It can use Graflex reflectors and electrical extensions.

Here is a diagram of a typical unit (http://www.digoliardi.net/scan_2.jpg), including the bulb adapter for edison/mazda bulb to smaller ones.

The cam has an adjustable delay (http://www.digoliardi.net/flasht_tronic_cam.jpg).

Harold_4074
2-May-2015, 08:00
The higher the current, the sooner the bulb fires. For synchronized flash, milliseconds count and the BC (battery-capacitor) flashes of the 1950s and '60s were a way to get amperes of current from a battery small enough to fit into one of the collapsible-reflector shoe-mount units for 35mm cameras. Obviously, a bit of delay in igniting an open-flash bulb is not critical, and the actual current needed is not all that much if one can wait for the igniter to heat up. The higher the current, the sooner the bulb fires.

One of the product warnings for the medium-base bulbs was to always handle them with gloves---static electricity can fire one, and the combination of heat and ultraviolet light will give you a pretty badly burned hand. When I was about nine, I found some of these bulbs, and fired one with a car battery...while holding the bulb in my left hand. Not gonna make that mistake ever again!

Randy Moe
2-May-2015, 18:18
The higher the current, the sooner the bulb fires. For synchronized flash, milliseconds count and the BC (battery-capacitor) flashes of the 1950s and '60s were a way to get amperes of current from a battery small enough to fit into one of the collapsible-reflector shoe-mount units for 35mm cameras. Obviously, a bit of delay in igniting an open-flash bulb is not critical, and the actual current needed is not all that much if one can wait for the igniter to heat up. The higher the current, the sooner the bulb fires.

One of the product warnings for the medium-base bulbs was to always handle them with gloves---static electricity can fire one, and the combination of heat and ultraviolet light will give you a pretty badly burned hand. When I was about nine, I found some of these bulbs, and fired one with a car battery...while holding the bulb in my left hand. Not gonna make that mistake ever again!

Now that you say that, I think that was a favorite stunt to pull on the unsuspecting.

I now remember somebody showed me a wire, a flash bulb and a car battery, and sure enough the joke was on me. The cruel 50's as I call them.

Now I have found a use for that stupid windup flashlight my employer once gave me as reward for being a fool.

It's a generator with a capacitor and a battery and will be good for popping flashbulbs!

If I can only find it...

Randy Moe
4-May-2015, 21:27
Back to business.

Some won't like this but the best definition of WS and Lumens is found on Paul C Buff. He clears up a few things for me. If you disagree, please tell us why. http://www.paulcbuff.com/sfe-unitsofmeasure.php

He rates his Einsteins at 28,000 lumen seconds, which I believe is close to the 25,000 Lumens of a Press 25. Which may mean with a same type and size reflector they produce the same amount of flash light power , but with different color temp and duration. http://www.paulcbuff.com/e640.php

This gives me something to test, I can pop a strobe and a single P25 and expose both DSLR and film at similar ISO and see what I get.

Soon this will happen.

Randy Moe
7-May-2015, 15:45
My research has been tested. i just got C batteries.

I used DSLR at ISO 100 Full Dark studio, 5 sec @f16. First image is Einstein full power. Second image is P5 flashbulb.

I had guessed they were close and I think they are. Both were dull aluminum cone reflectors 9" and 11" respectively. They were fired about the same height and distance, 3' apart.

A lot of light in one egg sized flashbulb and very portable.

As an afterthought I have added a 3rd image shot with ISO 100, 1/5 sec @f16 2K Mole Fresnel.

133514133515133516

Jac@stafford.net
7-May-2015, 16:21
My research has been tested. i just got C batteries.

I used DSLR at ISO 100 Full Dark studio, 5 sec @f16. First image is Einstein full power. Second image is P5 flashbulb.

I had guessed they were close and I think they are. Both were dull aluminum cone reflectors 9" and 11" respectively. They were fired about the same height and distance, 3' apart.

The lights appear to be at different angles, but yes, pretty darned good for testing considering that you don't have a lot of bulbs to spare. Ain't it amazing how much light there is in a 25 bulb? (BTW, for the others because you know, the 25 bulb refers to its ~1" diameter in mm.)

Randy Moe
7-May-2015, 16:37
The lights appear to be at different angles, but yes, pretty darned good for testing considering that you don't have a lot of bulbs to spare. Ain't it amazing how much light there is in a 25 bulb? (BTW, for the others because you know, the 25 bulb refers to its ~1" diameter in mm.)

Yes, it was different angles, 3 ft apart. I didn't want to move everything as there is no room in here.

The P5 bulb preceded the P25 bulb, I yet they are interchangeable I believe. They are the same diameter. Are you sure it's a metric assignation? Seems kinda odd for something made in the 30's and 40's

I have plenty of bulbs for this summer. 1000+ M2, M3: 500 P5, P25: 300 AG1 and 100 #5. Assorted medium base of varying power.

And all the gear to pop them anywhere.

They call me the Flash. No they don't...

Randy Moe
7-May-2015, 22:01
Adding 1 more bulb type in the same 11" reflector. It is becoming my favorite.

A M2B flashbulb which I calculated as 3 stops slower than P5. This is a blue coated Color film bulb the size of a grape. A dozen fit in a back pocket in the OE box.

Shot ISO 100 f5.6 open bulb. I am only going to figure out B&W as I use digital for all color at this time. The camera is set to B&W.

I am finding Lumens and GN to correlate different bulbs useful. But all these bulbs in their different era boxes have different ways of 'helping' the shooter.

Even the 50's fancy BC flash holders use a variety of 'tips'. No real standards I guess. They say the same of modern strobes.

I need to make cheat sheets, 'as my head is like a sieve', if you know that song...I'm not using a meter, preferring to find the basics.

After the DSLR tests, do them all over on HP5 and X-Ray. Then I start shooting 8x10 in the dark. If I can find a dark spot in Chicago...

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BrianShaw
8-May-2015, 06:31
So speaking of cheat sheets, I use 2: Kodak Photoguide calculators (most of the time) and a LawrenceWalsh FlashRule. Have you compared any of your tests against them?

Randy Moe
8-May-2015, 07:53
So speaking of cheat sheets, I use 2: Kodak Photoguide calculators (most of the time) and a LawrenceWalsh FlashRule. Have you compared any of your tests against them?

I am using a NOS Lawrence Walsh Flash Rule, a cool wood slide rule but I don't have the Kodak one. I am checking 'guides' against each other. Some of these bulbs are not marked.

This is a big help found on APUG. 133535

BrianShaw
8-May-2015, 10:20
Can't wait to hear results of your analysis. The old Kodak calculator is my favorite because it reminds me of the efficiency correction based on shutter speed. I have a couple of the slide rules but haven't used them much because I keep getting a gut feeling that the sliderule answer is different from the photoguide answer... and photoguide has worked well for me even with E-6 so it must be right on. But I'm either too busy or too lazy to compare the two.

I have a random assortment of those bulb manufacturer guides but that one doesn't look familiar. Thanks. The GNs those guides provided seem quite right-on to me in my experience.

Jac@stafford.net
8-May-2015, 10:32
Another tip from the flashbulb era: When you want to add light, wedge another bulb behind the socketed one. The socketed bulb will set off the other one, and create a longer duration. Oh, and the fun factor - it's dangerous, too!

Speaking of calculating flash. I have a very old flashbulb 'meter'. It is a rangefinder with a slide-rule type wheel attached.

Randy Moe
9-May-2015, 18:26
Yes, Jac, I have read that one bulb will fire another (secondary ignition) and a whole bag, pocket or box can make some excitement and danger.

I am not one of those 'static' people who spark on everything.

I will try my best to not hurt myself or others. Notice the shields and I just bought the shield a member was selling here today.

Here's my flash gear I will be using in a variety of ways.

I will soon test with 35 mm film of the same type I will use for LF and ULF.

I know most here know this, but the light needed for tiny format is the same as ULF, given all other factors are the same, such as shutter speed, aperture, filter, distance, ISO.

The tiny Honeywell Tilt A Lite has a unique bulb socket that mounts AG1, M2, M3, M5 and Press 25 bulbs by just pushing them in. The entire Tilt a Lite folds up and goes in a small shirt pocket.

Even cooler is the tiny AG1 has the same power as the Press 25B bulb the size of an egg.

Testing with Nikon F5 soon.

First I am going to DSLR video at 60 fps to look at flash duration. I can't shoot video any faster, 60 fps may be too slow. Need a high speed camera...

After looking at my video, I am going to choose a shutter speed, probable 1/25 as that is the speed of a Packard and most of my lenses I will be using don't have the old time 'M' setting which as Jac pointed out, fires the flash before the shutter to match them up.

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Harold_4074
10-May-2015, 11:00
Need a high speed camera...

How about a slow camera and a fast measurement?

Make a cardboard disk (black with a white radial stripe) and spin it in a variable-speed drill. Photograph with your 60 fps video while you fire the bulb. The width of the blur will give you the flash duration in fractions of a rotation period, and the video will tell you what that period is.

Ignition delay may be more important than duration, but if you fire a strobe simultaneously with the bulb, you may be able to get a good estimate of that, too.

Randy Moe
10-May-2015, 11:04
Need a high speed camera...

How about a slow camera and a fast measurement?

Make a cardboard disk (black with a white radial stripe) and spin it in a variable-speed drill. Photograph with your 60 fps video while you fire the bulb. The width of the blur will give you the flash duration in fractions of a rotation period, and the video will tell you what that period is.

Ignition delay may be more important than duration, but if you fire a strobe simultaneously with the bulb, you may be able to get a good estimate of that, too.

Great ideas. I like them both and will try them.

Thanks.

Randy Moe
10-May-2015, 11:41
Her's a separate question, that this thread may be able to handle.

I want to fire an electronic flash, Nikon SB800 in a random sequence for 2 hours with a known flash total count without a camera connected.

Any cheap simple ideas?

It's retinal memory project.

and LF open bulb image.

This is a cool idea (http://nofilmschool.com/2014/12/shooting-timelapse-got-simple-pico-timelapse-controller), but may not do what I want. I placed an order however it ships late for my project.


I may be able to make it work with a relay to buffer the electronics.

Harold_4074
12-May-2015, 12:56
If you speak even pidgin digital, you can breadboard a linear-feedback shift register for practically nothing. Use a 555 timer for the clock, and either 7474 flipflops or a multiple-FF package for the register. The minimum interval would be one clock period, and the maximum would be determined by the length of the register; for photography, you might want to bound the minimum interval by using a second 555 and gating out pulses which fall within its period. Finally, a one-shot at the output will give you trigger pulses that are short in comparison to clock period.

The poor man's solution to noise immunity (important if there is a lot at stake) is to put the circuit inside a metal box, running off of battery power, and bring out only the normally-open contacts of a small relay.

You could also do this with industrial time delay relays, which would be fun to watch but pretty expensive.

Randy Moe
12-May-2015, 13:04
I have been studying the 555's. Some of the usual socket based industrial timers are pretty cheap now, I have used those many times, but never paid the price 20 years ago as they were $100s, now offshore is not.

Last night I gave up on random, as I found it not necessary for my secret project.

My Nikon P7000 will fire an external flash every 30 seconds which works for me.

I will try the cheap intervalometer to streamline my system when it gets here.

DrTang
12-May-2015, 13:06
Yes, Jac, I have read that one bulb will fire another (secondary ignition) and a whole bag, pocket or box can make some excitement and danger.


met an oldtimer at a camera swap meet once who's hand was all messed up - seems he was reaching into a box of loose flashbulbs and static electricity set one off - setting them all off

Randy Moe
12-May-2015, 13:49
met an oldtimer at a camera swap meet once who's hand was all messed up - seems he was reaching into a box of loose flashbulbs and static electricity set one off - setting them all off

I fell off a perfectly fine motorcycle and hurt myself.

I still ride and have for 50 years.

Jac@stafford.net
12-May-2015, 16:52
I want to fire an electronic flash, Nikon SB800 in a random sequence for 2 hours with a known flash total count without a camera connected.
What do you mean by a random sequence? Do you mean a device will choose to fire the flash on its own with random intervals? I do not know of any.

The SB800 has two flash synch terminals and one is intended for non TTL use. Can you use a terminal adapter and an ordinary, inexpensive intervalometer to fire it?

Randy Moe
12-May-2015, 17:11
What do you mean by a random sequence? Do you mean a device will choose to fire the flash on its own with random intervals? I do not know of any.

The SB800 has two flash synch terminals and one is intended for non TTL use. Can you use a terminal adapter and an ordinary, inexpensive intervalometer to fire it?

#1 Yes, but I have moved on to sequential after last night's experiments. I can calculate total flash power easier when using many instances.

#2 That is why I am waiting for the Canon Intervalometer I linked to, Canon because it has a 3 wire interface, but it's designed to fire a camera and not a strobe. Einstein or SB800 may have a higher shorting current than a camera. I will not be using flash bulbs for this.

I try not to break things...

Randy Moe
15-May-2015, 22:53
I didn't buy the cheap Canon Intervalometer, I bought the cheap Nikon version as it can do 2 things for me. One it works as advertised with my D7000. Not a waste of $15. This one on eBay. (http://www.ebay.com/itm/161694325133?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT)

Most importantly it can time and fire Nikon SB28 repeatedly in sequence. It may work with any modern strobe, but I am not testing it further.

One practical usage is paint by light with strobe, using open bulb shutter at night. Very applicable to LF shooting or any format.

I was worried the SB28 may blow the circuitry on the timer, but I just ran it for an hour every 10 seconds. I used SB28 as it has paid it's way for 18 years. Almost expendable.

Since timer has a stereo mini phono I plugged a PC to mini mono phono plug in and bingo it works perfectly. No tinker needed. Plug and Play.

My plan for this combo uses a 32" silver umbrella with GoBo, which when viewed at night at a distance will create retinal images, which are fleeting mind/eye photographs, organically imprinted, not digital and not based in physical materials as we commonly think of photography. It will produce an ULF image, 32". Impossible to show in any way except by high speed video. Yet humans perceive it easily.

I think this will puzzle, enthrall young at heart, anger others, when it debuts in a month.

Maybe it already angers some here, as not photography, but I maintain it is imaging, hence it is photography.

I'll update the actual imaging results and viewing reaction in a month with explanation of delivery and purpose. Secret until tactique du fait accompli. French says it better, but I don't know French...







That's my story and I'm sticking to it.

Jac@stafford.net
16-May-2015, 08:33
#1 Yes, but I have moved on to sequential after last night's experiments. I can calculate total flash power easier when using many instances.

Mentioning this for the readership - it is good to keep in mind that multiple short exposures of a film do not equal the sum, tending to underexposure.