Coldkennels
Barnack-toting Brit.
Let me start this post by putting my hands up and saying I've never once fired a flash bulb. I've only ever known electronic flash - and frankly, I've never really liked the look of electronic flash, and no amount of soft boxes and bounce flashes can change that for me.
Despite that, I've owned a Leica IIIf for well over a decade at this point and the flash sync dial has always got me curious. Having accidentally obtained a basic bulb flashgun (an Zeiss Ikoblitz 4), I thought I'd give bulbs a go and see if I'm happier with the results; as such, these turned up this morning:
According to data I've found on the internet (Philips Flashbulb Data - Cress Photo - Flashbulbs.com), these should have the same burn time/peak as the PF45 - which helpfully is listed in the supplementary instructions for the black dial IIIf (https://www.cameramanuals.org/leica_pdf/leica_iiif_supplementary.pdf), so I have the sync settings I need.
My question now is exposure; I understand how guide numbers work when you have them (divide the GN by the distance to subject to get the aperture), but the guide numbers on the back of the box for these bulbs only run from 1/50 to 1/500:
Is there a way to figure out the missing numbers? I'd assume you just open up or stop down 1 stop from the last known measurement (e.g. if it's f/11 at 1/500, f/16 at 1/1000 should do), but I wanted to check I wasn't missing something.
Similarly, the listed speeds stop at 200 ISO; I'd also assume I can just close down the aperture one stop if I was shooting a 400 ISO film?
The other question I have relates to focal length. With every electronic flash I've used, you need to take into account coverage; the standard head position and guide numbers only really apply for 50mm. Is that also true with bulb flashes, or will these things cover wide-angle lenses without any additional considerations?
Despite that, I've owned a Leica IIIf for well over a decade at this point and the flash sync dial has always got me curious. Having accidentally obtained a basic bulb flashgun (an Zeiss Ikoblitz 4), I thought I'd give bulbs a go and see if I'm happier with the results; as such, these turned up this morning:
According to data I've found on the internet (Philips Flashbulb Data - Cress Photo - Flashbulbs.com), these should have the same burn time/peak as the PF45 - which helpfully is listed in the supplementary instructions for the black dial IIIf (https://www.cameramanuals.org/leica_pdf/leica_iiif_supplementary.pdf), so I have the sync settings I need.
My question now is exposure; I understand how guide numbers work when you have them (divide the GN by the distance to subject to get the aperture), but the guide numbers on the back of the box for these bulbs only run from 1/50 to 1/500:
| Shutter | Sync | GN (m, 100ISO) | GN (ft, 100ISO) |
|---|---|---|---|
| 1/30 | 20 | ? | ? |
| 1/40 | 15 | ? | ? |
| 1/60 | 11 | 38 | 124 |
| 1/100 | 7.5 | 26 | 88 |
| 1/200 | 5 | 18 | 58 |
| 1/500 | 4 | 13 | 44 |
| 1/1000 | 3 | ? | ? |
Is there a way to figure out the missing numbers? I'd assume you just open up or stop down 1 stop from the last known measurement (e.g. if it's f/11 at 1/500, f/16 at 1/1000 should do), but I wanted to check I wasn't missing something.
Similarly, the listed speeds stop at 200 ISO; I'd also assume I can just close down the aperture one stop if I was shooting a 400 ISO film?
The other question I have relates to focal length. With every electronic flash I've used, you need to take into account coverage; the standard head position and guide numbers only really apply for 50mm. Is that also true with bulb flashes, or will these things cover wide-angle lenses without any additional considerations?
Malcolm M
Well-known
When the blind leadeth the blind, they both shall fall into the pit, but here goes anyway....
Presumably 1/50th is the duration of the flash. Longer shutter speeds will have no effect on exposure and can use the same guide number.
Maybe it's best not to use 1/1000.
I would assume the same as you for different film speeds.
I presume different guide numbers for different focal lengths applies to electronic flashes with telescoping lenses over the tube to widen/ narrow the coverage. Bulb flashguns don't have this facility. Your guide number is your guide number is your guide number.
Presumably 1/50th is the duration of the flash. Longer shutter speeds will have no effect on exposure and can use the same guide number.
Maybe it's best not to use 1/1000.
I would assume the same as you for different film speeds.
I presume different guide numbers for different focal lengths applies to electronic flashes with telescoping lenses over the tube to widen/ narrow the coverage. Bulb flashguns don't have this facility. Your guide number is your guide number is your guide number.
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Coldkennels
Barnack-toting Brit.
The Cress Photo link in my first post says the flash duration at half peak is 15 milliseconds, which is about 1/65th, so you might be right on that one. But that doesn't account for the "tail" on each side of the curve -
- so I assume the guide number must change, albeit slightly, to accommodate that extra light. Right?
Auto-thyristor flash units must have been absolutely revolutionary when they were invented. Doing things "the old way" is such a headache in comparison!
seany65
Well-known
Hmm, speeds longer than 1/50th may not affect the exposure of the subject to be photographed, but am I right in thinking that the longer the shutter speed being used the lighter the background will be?
Bill Jones
Contax Lens User
These FP bulbs were made for syncing at high shutter speeds where the shutter speed and not the flash duration set the exposure time. They were an outlier in their day, I suggest trying an AG bulb instead. Their use will be more familiar.
Seany is correct about the shutter speed effect on backgrounds with fill flash.
Malcolm remarks are also correct.
Bill
Coldkennels
Barnack-toting Brit.
This was actually the main reason I bought these bulbs in particular! With the IIIf allowing for adjustable sync timing, using them at 1/250 seemed like a great way to make flash use a bit more versatile. But when you say...
...does that also hold true for the focal length issue? For instance, as long as I've got a decent reflector behind them, am I likely to get enough coverage for a 28mm lens?
Rob-F
Likes Leicas
Looking at this chart, the guide numbers don't double or half between successive shutter speeds. For example, from 1/200 to 1/100 the guide number doesn't go from 18 to 36; it goes only from 18 to 26. Notice this: 26/18 = 1.444, which is very close to the square root of two (1.414). So the guide number should be adjusted, between shutter speeds that are exactly double or half, by just 1.414. Notice that the guide number doubles or halves, not for a one-stop change, but for a two-stop change: from 1/200 to 1/60, the guide number changes from 18 to 38, essentially a one stop change, since 200 isn't exactly four times 60, either. And from 1/500 to 1/100, there is again a double or half relationship.
So, the change in guide number increases by a factor of 1.414 when the shutter speed is one stop slower; and decreases by a factor of .707 (the square root of two over two) when the shutter speed is one stop faster. So to extrapolate the guide number from 1/500 to 1/1000, we have 13 x 0.707 = 9.19, or about 9.
It's all because successive f numbers are in a square root of two relationship, for example, f/4 is f/2.8 x 1.414; f/5.6 is 4 x 1.414, and so on. And for a two-stop change, the f/number does double or half (f/4 x 2 = f/8).
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x-ray
Veteran
I’ve used many cases of flash bulbs from AG1 up to #3 in the 60’s into the 80’s though I can’t say I’ve used many FP bulbs. Still I know a bit about them.
The reason that data at the slow end of the shutter speeds is most likely due to there’s no reason to use a FP bulb if you’re below your sync speed. Conventional M class bulbs will do just as good a job because your shutter is totally open when the bulb ignites therefore you’re getting the entire peak despite its shorter peak duration. Think of it this way, on M sync the shutter opens fully at 1/30 then the bulb fires while the shutter is fully open. It reaches peak in less than 1/30 then the shutter closes. You’ve used the entire usable peak of light.
At higher shutter speeds there’s only a segment of the film being exposed at one time. A slit in the shutter travels the length of the film but only a small part of the film is exposed at one time. When you trigger an FP bulb using the FP sync, the bulb ignites as soon as the shutter is tripped, no delay like M sync. The shutter may even be delayed allowing the bulb to come up to peak before the shutter moves. The bulb reaches peak and the shutter traverses the film using only the peak output of the bulb. If the shutter moves too early or sync is off you’ll get uneven exposures across your film.
For sync under your sync speed use AG1, M2, M3, 25 or 5 bulbs. They’re good for slow speeds but aren’t good for fast shutter speeds because the peak is too short.
Bulbs designated with a B are daylight balanced.
The size and finish of the reflector makes a big difference in guide number. Polished reflectors are much more efficient than satin and the folding fan type that were popular with amateurs.
Take care inserting the bulb in the flash. I learned the hard way how static can ignite a bulb and how flash guns can malfunction and ignite the bulb in your fingers. I always used a cloth to insert the bulb or on large bulbs, #11, 22, 3’s I used the cardboard sleeve they came in. Even then they’ll burn the crap out of you if it fires. I’ve left the fried skin on my fingers on a few flash bulbs before. 😖
Another tip, the connectors of a flash bulb like yours and larger bulbs have a lead solder joint on the bottom of the connector. It oxidizes and will keep your bulb from igniting. I used to have a small piece of fine grit sandpaper on the base of my flash and scraped it on that sandpaper before putting in the flashgun. You could scrape it on a concrete floor or bottom of your shoe too. Old timers used to link but you get lead that way.
If you really get into it find an old Kodak Master Dataguide. It has a ton of info.
Have fun with them.
The reason that data at the slow end of the shutter speeds is most likely due to there’s no reason to use a FP bulb if you’re below your sync speed. Conventional M class bulbs will do just as good a job because your shutter is totally open when the bulb ignites therefore you’re getting the entire peak despite its shorter peak duration. Think of it this way, on M sync the shutter opens fully at 1/30 then the bulb fires while the shutter is fully open. It reaches peak in less than 1/30 then the shutter closes. You’ve used the entire usable peak of light.
At higher shutter speeds there’s only a segment of the film being exposed at one time. A slit in the shutter travels the length of the film but only a small part of the film is exposed at one time. When you trigger an FP bulb using the FP sync, the bulb ignites as soon as the shutter is tripped, no delay like M sync. The shutter may even be delayed allowing the bulb to come up to peak before the shutter moves. The bulb reaches peak and the shutter traverses the film using only the peak output of the bulb. If the shutter moves too early or sync is off you’ll get uneven exposures across your film.
For sync under your sync speed use AG1, M2, M3, 25 or 5 bulbs. They’re good for slow speeds but aren’t good for fast shutter speeds because the peak is too short.
Bulbs designated with a B are daylight balanced.
The size and finish of the reflector makes a big difference in guide number. Polished reflectors are much more efficient than satin and the folding fan type that were popular with amateurs.
Take care inserting the bulb in the flash. I learned the hard way how static can ignite a bulb and how flash guns can malfunction and ignite the bulb in your fingers. I always used a cloth to insert the bulb or on large bulbs, #11, 22, 3’s I used the cardboard sleeve they came in. Even then they’ll burn the crap out of you if it fires. I’ve left the fried skin on my fingers on a few flash bulbs before. 😖
Another tip, the connectors of a flash bulb like yours and larger bulbs have a lead solder joint on the bottom of the connector. It oxidizes and will keep your bulb from igniting. I used to have a small piece of fine grit sandpaper on the base of my flash and scraped it on that sandpaper before putting in the flashgun. You could scrape it on a concrete floor or bottom of your shoe too. Old timers used to link but you get lead that way.
If you really get into it find an old Kodak Master Dataguide. It has a ton of info.
Have fun with them.
Attachments
CMur12
Veteran
If you had spent your childhood, lined up with your cousins at every family gathering, while every aunt and uncle blinded you with their flash bulbs, you would think more kindly of electronic flash.
One brand cynically named their product "Blue Dot" flash bulbs (I believe the blame goes to Sylvania). I literally saw a blue dot before my eyes for some duration after every flash!
If anyone ever wants to take your picture with a flash bulb, close your eyes! (To hell with the picture.)
- Murray
One brand cynically named their product "Blue Dot" flash bulbs (I believe the blame goes to Sylvania). I literally saw a blue dot before my eyes for some duration after every flash!
If anyone ever wants to take your picture with a flash bulb, close your eyes! (To hell with the picture.)
- Murray
x-ray
Veteran
Do you know the significance of the blue dot? If the dot was blue the bulb was good. If the dot was pink/red it was bad. The GE logo on the end of their bulbs did the same thing.If you had spent your childhood, lined up with your cousins at every family gathering, while every aunt and uncle blinded you with their flash bulbs, you would think more kindly of electronic flash.
One brand cynically named their product "Blue Dot" flash bulbs (I believe the blame goes to Sylvania). I literally saw a blue dot before my eyes for some duration after every flash!
If anyone ever wants to take your picture with a flash bulb, close your eyes! (To hell with the picture.)
- Murray
You’re right about the blue dot in your eyes after the flash.
CMur12
Veteran
I didn't know that about the actual reason for the blue dot! Good to know after all this time.
(I don't think I ever had any that went bad, as I don't remember ever seeing a pink/red dot on the end of my flashbulbs.)
- Murray
x-ray
Veteran
I’ve only seen a handful and the dot was correct, they didn’t ignite.
raydm6
Yay! Cameras! 🙈🙉🙊┌( ಠ_ಠ)┘ [◉"]
I was thinking about those Blue Dot flashcubes (4 flashes per cube) recently per @x-ray's Are you old enough to remember? thread.
Cool retro article here with vintage ads for those who didn't experience this era:
clickamericana.com
Lots of flashcubes/Magic Cubes for sale on the auction site.
Never had this happen though:
canistermagazine.com
Cool retro article here with vintage ads for those who didn't experience this era:
Vintage flashcubes: How these old camera add-ons worked & made pictures brighter - Click Americana
In the '60s, new camera tech meant vintage flashcubes. These inventions were jewel-like cubes that comes with four full-power flashbulbs sealed inside. See how they worked!
clickamericana.com
Lots of flashcubes/Magic Cubes for sale on the auction site.
Never had this happen though:
Photography With Tiny Explosives
Magicubes provided a cheap flash for 1970s camerasâââby blowing themselves up
canistermagazine.com
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Coldkennels
Barnack-toting Brit.
There's a lot of solid advice there, X-ray. Thanks for this - lots to take on board. However, these two points left me confused/concerned: has no one accidentally created a spark by trying to clean the oxidised solder on something and set the bulb off? Seems like a risky move!
When I first started seriously looking into using bulbs a couple of years ago, I heard so many horror stories of photojournalists carrying bulbs in their pockets and accidentally setting them off somehow, causing severe burns to their thighs. Or there's my absolute favourite - a guy rigging up his brand-new flashgun on the bleachers at a basketball game (so very high-powered bulbs!), and accidentally setting it off in his lap while pointed directly at his face. Poor guy thought he'd legitimately gone blind for five or ten minutes.
To say that put me off the idea was an understatement!
x-ray
Veteran
High energy like radar can ignite them. Some bulbs contain a gas plus igniter and most contain a spun metal of zirconium magnesium aluminum alloy and sn igniter.
The way they ignite accidentally while putting a bulb in the flashgun is if certain types of leaf shutters are open for focusing the flash contacts in the shutter are closed and will cause the bulb to fire. A short in the flash cord can cause that as well. I personally have had both happen and It’s very painful I can honestly say.
I have a small collection of bulbs from the AG1 up to the large FF33 and the #3. I even have one that’s Infrared and emits no visible light. I’ll pull them out later today and snap a quick photo.
I have about a case of 5 & 25’s and have a project in mind I want to do. I want to recreate some of the Weegee crime scenes in alleys and streets with actors and photograph them on my Crown Graphic with flash bulbs at night. I need to get project that going now that I’m retired.
The way they ignite accidentally while putting a bulb in the flashgun is if certain types of leaf shutters are open for focusing the flash contacts in the shutter are closed and will cause the bulb to fire. A short in the flash cord can cause that as well. I personally have had both happen and It’s very painful I can honestly say.
I have a small collection of bulbs from the AG1 up to the large FF33 and the #3. I even have one that’s Infrared and emits no visible light. I’ll pull them out later today and snap a quick photo.
I have about a case of 5 & 25’s and have a project in mind I want to do. I want to recreate some of the Weegee crime scenes in alleys and streets with actors and photograph them on my Crown Graphic with flash bulbs at night. I need to get project that going now that I’m retired.
x-ray
Veteran
I recently say a bulb from the WWII era designed for night aerial photography. It was 6-7” in diameter. I’d never seen one before.
If you want to see some very cool night photography with bulbs look up O.Winston Link. He was a master with home made flash gear photographing trains at night.
I met him years ago in Roanoke and had a bulb in my car. I asked him to autograph it and he looked at me like I was nuts but did sign it. I still have it and will photograph if too.
If you want to see some very cool night photography with bulbs look up O.Winston Link. He was a master with home made flash gear photographing trains at night.
I met him years ago in Roanoke and had a bulb in my car. I asked him to autograph it and he looked at me like I was nuts but did sign it. I still have it and will photograph if too.
x-ray
Veteran
x-ray
Veteran
These are a bit unusual. The black one is a GE 5 IR that’s infrared only. The second is a #31 probably from the20’s or 30’s. I believe the material inside is a magnesium alloy. And the last is an FF33 with a 1.75 second peak used for ultra high speed motion picture. I used them to light things I filmed at 44,000 frames per second. The Shutter-Speed was 1/100,000 of a second.
Attachments
x-ray
Veteran
Coldkennels
Barnack-toting Brit.
I assume that black one is the style that Weegee famously used in movie theatres?
I always loved these photos, but god, do they look creepy!