using flashmeter for bulbs

[phil sweeney]

Though flash bulbs are expensive, I have decided it is still affordable compared to flash equipment. At least for an occasional portrait. I was told flashmeters do not work well with bulbs. Curious your responses to that. My thought is the meter would respond to initial output and would register before the bulb is at max intensity?

I was also told that the PF300 bulbs would be brutal on the model. Not the intensity but the duration. It was suggested a 22 euro would be a better pick. I want to use the 8 x 10 but I am not sure the 22 euro will be enough light. So I may have to use a 4 x5.

I'd appreciate any advice!

[Ralph Barker]

I've never tried metering flash bulbs, so take my thoughts with a pinch of flash powder, Phil. I'd think, however, that a flash meter might miss the bulb's output altogether due to the difference in sync delay.

The format itself won't affect the results, of course - just the potential limitations of the aperture range available on your 8x10 lenses, along with DOF considerations.

The larger issue, I'd think, would be the quality of light produced by the bulb, and options available to modify that. Even with long-duration bulbs, the flash would be more kind to the subject than hot lights that would allow the same aperture.

[Mark Sampson]

I once took a flashbulb (one with a household lamp base) and put it in a ceiling fixture. Triggered the flashmeter and hit the light switch. POP- f/16 on the meter. I never tried taking a photo with that lighting- perhaps the longer duration of the flashbulb might give more light than was metered. A test with film would answer that. But I'd be as concerned with the quality of light produced, or at least how to preview it. O.Winston Link used to hard-wire his huge sets for photographing steam locomotives at night.. miles of lamp cord... and would test the setup with ordinary lightbulbs. Whe continuity was assured, they would then replace all the lightbulbs with flashlamps. Perhaps you could predict your lighting the same way?

[Paul Ewins]

Phil, you're right that a flash meter won't work properly with bulbs. Because the bulbs take time to reach full power and then more time to drop back to zero power again the behaviour is quite different to a strobe. A strobe is faster than a shutter, so no matter what speed you use you get the same amount of light from the strobe reaching the film. A bulb can be slow enough that the faster shutter speeds allow less light to reach the film.

I've been using a variety of bulbs with my Speed Graphic set-up and have found the little tables on the back of most flash bulb packets to be quite accurate. The size of the bulb is not necessarily a good indicator of its power as improving technology allowed them to shrink quite rapidly in size. The bulbs I'm using are anywhere from 20 to 40 years old and dud bulbs have been very rare.

One thing to be aware of is the size of the reflector. A smaller reflector concentrates the light, so is brighter but gives less coverage. With a 5" reflector and the standard 135mm lens the edges of the negs are usually dark, so I really should be using a 7" reflector for full coverage.

I can't imagine why you would use the meggaflash bulbs, the are so expensive compared to secondhand. I normally buy from eBay and flea-markets and try to pay no more than 50 cents each for small bulbs. There are still an awful lot of bulbs out there if eBay is anything to go by.

Check out Bill Cress at www.flashbulbs.com as he has a lot of information there and has all the various bits and pieces you might need. His prices reflect the fact that he is running a business rather than just off-loading stuff found in the attic, but the service you get is much higher too. I certainly haven't regretted any purchases made from him.

[Walt Calahan]

Exactly, the meter would not record the entire flash from the flash bulb because it has such a long burn time.

This is way lenses have X and M settings. X for the instant burst of the strobe. M to delay the opening of the shutter so it is open when the flash bulb is at its maximum brightness.

[phil sweeney]

Thanks for the info. I have not bought the PF300s yet but have purchased some older ones a little cheaper.

I can fire the bulb from my meter. If I select a sync time greater than the duration of the lamp burn time wouldn't that be a good measurement?

[Michael Gudzinowicz]

Consider running a simple test to equate the f/stop required with flashbulbs @ 1/30th sec with tungsten modeling lamps. Set up a pan reflector with lamp socket (Smith Victor or similar tungsten lamp) on a light stand, and using the published GN as a reference, do one or more test exposures using flash (plug the lamp cord into a circuit with batteries and the sync cord). Replace the flashbulbs with a tungsten lamp and AC power, and take an incident meter reading. Adjust the meter's EI setting and choose the shutter speed which gives the f/stop determined by flash tests.

For use, set up one or more tungsten lights anywhere (reflectors, diffusion panels, bounce cards, etc.), meter with the settings determined by the previous test, set f/stop, swap tungsten bulbs for flashbulbs and plug cords into battery adapter, and shoot. Meter again if the modeling lights/flashbulbs are moved. Of course, the tungsten lamps may be used for still life or portraits with slow shutter speeds. Also, a bare bulb flash held a foot or two from a white ceiling can light a room.

If you do this often, you might want to opt for a used studio flashpack. Although the initial cost is more than bulbs, the used resale value is considerably higher, and it's more convenient. I tend to reserve flashbulbs for outdoor use to stop motion and overpower daylight.

Mike.

[DrTang]

wow..I was thinking of posting just this and searched and here it is

with re: to the meter missing the flash - my minolta flashmeter III can be triggered by cord...or 'non cord' - so I can hit the button, then manually flash the flash and it'll read it


I imagine if one uses the 'non-cord' option..the meter would read the entire output of the bulb


I should give this a try


also..I bet I can use a bulb flash holder with an umbrella

[Jim Noel]

The meter willl not help. Use the guide number that should be on the bulb package. We used these for decades prior to the advent of electronic flash.

[AtlantaTerry]

This is why lenses have X and M settings.

May I point out that shutters have X / M settings, not lenses.

[Ian Gordon Bilson]

Of the various f/meters I have used,only one -Gossen Profi-flash,had a fixed "gate speed",at 1/125s.
But, I intend to test my Sekonic 408 now.
Thanks for the headsup.

[Jac@stafford.net]

The Sekonics made since at least the model L-308S can read flashbulbs in daylight. Be certain to use cord-mode and choose the correct shutter speed on the shutter, then set that shutter speed on the meter. Use M synch, of course. Not using cord-mode can lead to a complete failure of the meter to read because bulbs have a less profound onset than electronic flash, so that gross overexposure is likely - only the ambient will be measured.

[Jody_S]

The meter willl not help. Use the guide number that should be on the bulb package. We used these for decades prior to the advent of electronic flash.

If you want to know if your meter is working then, why not try it and compare the reading to the tables on the back of the flashbulb package? Or use a dSLR on 1/15 - 1/30 or so, to make sure it's reading the entire flash duration. For that matter, if your shutter doesn't have an 'M' mode, a few tests with a dSLR will also tell you your minimum shutter speed that will capture the flash output. It shouldn't take that many flashbulbs to test to get a baseline of how you need to meter before you start with the 8x10 sheet film.

[DrTang]

Okay - here is the deal

I have several barrel lenses that I was planning on shooting with my top rangefinder speed graphic -
on the side on the back of the camera is a fitting for a special flash cord that goes to a bulb flash reflector deal


what I want is..to use barrel lenses on my speed graphic... somehow synched to the back FPS ... and measure the bulb output with my minolta flashmeter III

I will probably be wanting to have the handle mount flash bulb deal with reflector aimed into a umbrella off camera


I don't want guide numbers..I don't have a shutter other than the built in FPS (which has a synch out so apparently it was made to work at some speed and with some bulbs)


am I living in a fools paradise?

[Jac@stafford.net]

I have several barrel lenses that I was planning on shooting with my top rangefinder speed graphic -
on the side on the back of the camera is a fitting for a special flash cord that goes to a bulb flash reflector deal

The cord you need is part #A20.

To fire flashbulbs with the focal plane shutter of a Speed Graphic you can use any flashbulb with a Time setting (position O). The unhappy news is that to use any setting other than Time, you need flashbulbs #31 or Superflash #2A . Shoot these at with focal plane duration of 1/1000 or 1/250 second but not 1/500. Yes, it's not intuitive.

I leave it to the reader to find equivalents to those two bulbs. Perhaps from Megaflash.

[DrTang]

The cord you need is part #A20.

To fire flashbulbs with the focal plane shutter of a Speed Graphic you can use any flashbulb with a Time setting (position O). The unhappy news is that to use any setting other than Time, you need flashbulbs #31 or Superflash #2A . Shoot these at with focal plane duration of 1/1000 or 1/250 second but not 1/500. Yes, it's not intuitive.

I leave it to the reader to find equivalents to those two bulbs. Perhaps from Megaflash.


whelp - that tears it

too much expense & trouble - I'll need to stick my barrel lenses into shutters with x synch then


thanks for the info

[Jac@stafford.net]

If it helps at all, it is not difficult to modify a Packard shutter to trip any flash when the blades reach wide-open.

I made a box that sits on a lensboard with a universal lens holder. The holder is large enough to accommodate lenses up to 3.5" diameter, and the shutter up to about 4.5".

EDIT: Forgive. I just found your post mentioning that you made a synchronizing Packard recently.
http://www.largeformatphotography.info/forum/showthread.php?106589-Simple-flash-sync-for-packard-shutters

[Brassai]

There are special bulbs available for focal plane shutters--they have "FP" after their size. I've used a couple with my Leica IIIf. If I remember right, they are designed to have a longer burn time so they will stay lit as the slit in the shutter moves around.

[Jac@stafford.net]

There are special bulbs available for focal plane shutters--they have "FP" after their size. I've used a couple with my Leica IIIf.

True, in part. Not all focal plane shutters work alike.

[Jim Jones]

There are special bulbs available for focal plane shutters--they have "FP" after their size. . . .

The FP-26 flash bulb reaches its peak output about 12ms after the sync contacts close, and declines to half-power at about 40ms. This seems too fast for a large format shutter. The larger type 2A reaches maximum output at about 18ms, and maintains much of this output to about 70ms.