John Shriver
Well-known
M3B's are incredibly common, although you've got a very limited choice of (slowish) shutter speeds to use them. The 6B and 26B can be rather hard to find, but give you great flexibility on shutter speeds.
goamules
Well-known
I have a bunch of M3s. I researched and read the specs tables for over a hour trying to figure out the settings to use. What a headache. I understand the Guide Number to figure out aperture. The micosync is the problem. I'm guessing a setting of 20 might work, at 1/25 or "X". Question; is this so slow I need a tripod? My intention is to use the camera/flash handheld, at the kid's next chorus event, or at parties. But a tripod would put a damper on the fun.
What's a good guesstimate setting that is "surefire" for M3 flashbulbs? I usually use 400 speed film, but could go for slower if needed....
What's a good guesstimate setting that is "surefire" for M3 flashbulbs? I usually use 400 speed film, but could go for slower if needed....
John Shriver
Well-known
That depends on the serial number of your camera. If it is 170,000 or above, you can use 1/125, micro-sync 0. If it is 169,999 or below, you can use 1/60, micro-sync 15.
If you're in low enough light that you need flashbulbs, it's quite likely that they will put out much more light than ambient light. I ambient light is really bright, you may get a "ghost" image from the non-flash-lit part of the exposure. But the peak of the flash light is very short, so the flash-lit part will freeze action. Same reason electronic flash works OK with the slow X-sync shutter speeds it requires.
Now, we are assuming that the M3 has similar "class M" characteristics to the bulbs that they list. The manual for the Model Y predates the M3. So I'd recommend a few shots on a test roll (taking notes) to see whether the entire frame is equally lit.
Of course, you choose your aperture based on the subject distance, buy dividing the distance into the guide number for the M3B. The guide number will come from the flashbulb box, based on your film speed.
With 400 speed films, you may have more flash power than you can handle, and may not be able to stop down enough for close shots. People used flashbulbs with Kodachrome II (ASA 25), not Tri-X. I'd say you probably want to use nothing faster than ISO 100. (Unless you have an ND filter handy.)
Note that you want blue flashbulbs for color film, you'll get very amber results from clear flashbulbs.
Getting FP class bulbs (GE 6B or or Sylvania FP26B) makes life a lot easier.
If you're in low enough light that you need flashbulbs, it's quite likely that they will put out much more light than ambient light. I ambient light is really bright, you may get a "ghost" image from the non-flash-lit part of the exposure. But the peak of the flash light is very short, so the flash-lit part will freeze action. Same reason electronic flash works OK with the slow X-sync shutter speeds it requires.
Now, we are assuming that the M3 has similar "class M" characteristics to the bulbs that they list. The manual for the Model Y predates the M3. So I'd recommend a few shots on a test roll (taking notes) to see whether the entire frame is equally lit.
Of course, you choose your aperture based on the subject distance, buy dividing the distance into the guide number for the M3B. The guide number will come from the flashbulb box, based on your film speed.
With 400 speed films, you may have more flash power than you can handle, and may not be able to stop down enough for close shots. People used flashbulbs with Kodachrome II (ASA 25), not Tri-X. I'd say you probably want to use nothing faster than ISO 100. (Unless you have an ND filter handy.)
Note that you want blue flashbulbs for color film, you'll get very amber results from clear flashbulbs.
Getting FP class bulbs (GE 6B or or Sylvania FP26B) makes life a lot easier.
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