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Thread: Using Sylvania Blue Dot #2 flashbulbs

  1. #1
    Randy Moe's Avatar
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    Using Sylvania Blue Dot #2 flashbulbs

    I usually shoot digital crowd documentation at this event, http://cimmfest.org/, this is year five. I am tired of blasting away with digital. No fun.

    I wanted to use Press 25 bulbs with a Press camera, I might find them in 3 days, might not. Any bulbs available in Chicago would be great. Press # 25 andor # 5.

    I do have a case of Sylvania Blue Dot #2 flashbulbs.

    I am sure these put out a lot of light.

    I need advice on how to use them, most likely for group shots on 8x10.

    Since I have fresh Ilford Delta 100 film I will use that, with Calumet C1 and Symmar-S f5.6 300 mm. Sure I could use studio flash or SB800's, but what fun is that. maybe for backup...

    How do I wire and fire?

    Maybe put them in SV reflectors?

    I can meter, but I bet, these are a known quantity and some guidelines exist.

    I have a four socket video light bar...

  2. #2

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    Re: Using Sylvania Blue Dot #2 flashbulbs

    I don't think you can meter bulbs. But they have guide numbers and if you divide GN by distance you'll get an aperture setting. Or, in the old Kodak photoguides there are calculators. Or, there were sliderules for bulb exposure determination.

    What do you mean by, "How do I wire and fire?" Flash handle and M-synch on the shutter. What else do you need to know?

  3. #3
    Jac@stafford.net's Avatar
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    Re: Using Sylvania Blue Dot #2 flashbulbs

    Quote Originally Posted by Randy Moe View Post
    I usually shoot digital crowd documentation at this event, http://cimmfest.org/, this is year five. I am tired of blasting away with digital. No fun.

    I wanted to use Press 25 bulbs with a Press camera, I might find them in 3 days, might not. Any bulbs available in Chicago would be great. Press # 25 andor # 5.
    Ya big silly! Next time a little advance notice would be good. I'm a bulb-flash guy. Got cases and cases of 'em and dozens of flash units of all kinds.

    The guideline for exposure is 'Guide Number' and it is printed on the box. Test first. A good flash meter will read bulb flash correctly, even in strong ambient light.

    One of my manual, spelunking flashes.
    Attachment 93484

    I don't know if your LF shutter has more than one flash synch delay (some have 3 or 4), so shoot at 1/50th or slower and be happy.

    To fire them you need a unit that matches the base of the flash. Some are Mazda/Edison screw base - same size as household sockets. There are adapters for #25 bulbs to screw base. (#25 gets their name from their 25mm diameter).

    All it takes to set off any flashbulb is 1.5V, but I use 4.5. What the heck.

  4. #4
    Randy Moe's Avatar
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    Re: Using Sylvania Blue Dot #2 flashbulbs

    # 2 bulbs are big with medium base, they don't fit my flash handle, I figure I need an external battery and a light bar. They screw into regular household sockets.

    While I have about 45 of them, I want to make each shot count.

    Says 3 to 120 volts. Can I use a small 12 volt motorcycle battery that is handy and not worry about my expensive Copal 3 shutter flash contacts? I know 12 volts is safe, but how much current, amps do these bulbs draw? Do I need a relay. etc...

    Here is what is printed on the box, mostly Greek to me!

    Click image for larger version. 

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    Quote Originally Posted by BrianShaw View Post
    I don't think you can meter bulbs. But they have guide numbers and if you divide GN by distance you'll get an aperture setting. Or, in the old Kodak photoguides there are calculators. Or, there were sliderules for bulb exposure determination.

    What do you mean by, "How do I wire and fire?" Flash handle and M-synch on the shutter. What else do you need to know?

  5. #5
    Randy Moe's Avatar
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    Re: Using Sylvania Blue Dot #2 flashbulbs

    Jac, it was a middle of the night realization. A 'flash' as it were...

    I have no time, well a little, the big group shots are Sunday, in tiny places. I have had trouble with 50 mm on FF Nikon, framing 50 people. They have to get very cozy.

    I will save these big guns until I do the group shots, now i want to find some 25's in Chicago. I am putting up a WTB in a minute. Ebay will be too slow. Local, if not I will use the Press camera with a nikon SB800 and make a show of it with the the 8X10 and these #2's Sunday.


    Quote Originally Posted by Jac@stafford.net View Post
    Ya big silly! Next time a little advance notice would be good. I'm a bulb-flash guy. Got cases and cases of 'em and dozens of flash units of all kinds.

    The guideline for exposure is 'Guide Number' and it is printed on the box. Test first. A good flash meter will read bulb flash correctly, even in strong ambient light.

    One of my manual, spelunking flashes.
    Attachment 93484

    I don't know if your LF shutter has more than one flash synch delay (some have 3 or 4), so shoot at 1/50th or slower and be happy.

    To fire them you need a unit that matches the base of the flash. Some are Mazda/Edison screw base - same size as household sockets. There are adapters for #25 bulbs to screw base. (#25 gets their name from their 25mm diameter).

    All it takes to set off any flashbulb is 1.5V, but I use 4.5. What the heck.

  6. #6

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    Re: Using Sylvania Blue Dot #2 flashbulbs

    That should fit in a Graflite with 7 inch reflector. Two or 3 D-cells i ssufficient. The GN on the box is for tungsten film so some adaption may be needed for other film. I use the Kodak Photoguide calculator and get good exposure every time. While making every shot count is a good goal, some "wastage" may be required to dial in the exposure. All of that gibberish on the box is to let you know that GN/distance=aperture, but there are also exposure impacts of reflector size and polish-ness, and shutter speed.

  7. #7
    Jac@stafford.net's Avatar
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    Re: Using Sylvania Blue Dot #2 flashbulbs

    Quote Originally Posted by Randy Moe View Post

    Says 3 to 120 volts. Can I use a small 12 volt motorcycle battery that is handy and not worry about my expensive Copal 3 shutter flash contacts? I know 12 volts is safe, but how much current, amps do these bulbs draw? Do I need a relay. etc...
    All you need is two D size batteries. Flashlight stuff. You will not hurt the Copal shutter. Believe me. Just NEVER use house current. I can explain in detail, but just don't.

    Your guide number is 320 (a compromise because size and shape of reflector matters. I'm giving the typical 7" reflector size. Divide the subject distance (in feet) into 320. Example: at 10 feet, that's F/32 @ 1/50th of a second for 100ISO film. Work from that. 20 feet would require F/16. It is almost intuitive.

    Ya gotta find a flash unit and proper synch cord.

  8. #8
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    Re: Using Sylvania Blue Dot #2 flashbulbs

    I have a PC to HH cord. I can mount the only flash unit I have to either the 2X3 or 4X5 in the image, but that flash needs # 25's

    I am thinking of gaffing a battery and a long cord to 2 SV reflectors. So 2 #25's at 20 feet in dull 10' aluminum cone reflector. Pictures shortly of those.

    hers's the press cameras and falsh unit, needs mounting, it came off a 3x4. I could use the 3X4, but i would need to cut film. I may just do that as it needs no mods and is not quite as nice as the 2 in the pic. It is also way lighter than that 4X5.

    Click image for larger version. 

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    Quote Originally Posted by Jac@stafford.net View Post
    All you need is two D size batteries. Flashlight stuff. You will not hurt the Copal shutter. Believe me. Just NEVER use house current. I can explain in detail, but just don't.

    Your guide number is 320 (a compromise because size and shape of reflector matters. I'm giving the typical 7" reflector size. Divide the subject distance (in feet) into 320. Example: at 10 feet, that's F/32 @ 1/50th of a second for 100ISO film. Work from that. 20 feet would require F/16. It is almost intuitive.

    Ya gotta find a flash unit and proper synch cord.

  9. #9
    Jac@stafford.net's Avatar
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    Re: Using Sylvania Blue Dot #2 flashbulbs

    Quote Originally Posted by Randy Moe View Post
    I have a PC to HH cord. I can mount the only flash unit I have to either the 2X3 or 4X5 in the image, but that flash needs # 25's

    Click image for larger version. 

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    Lucky you. Your flash handle (battery holder) has the 90 degree head adapter. Take it off! Voila, underneath is a screw base bulb holder. Just push the bulb down into the hole. Got another reflector? There is one that fits over the top, surrounding the top, leaving the hole for the bulb base, and the more typical version that fits via an extension into the tab on the rear.

    ...or tape a pie plate behind the bulb. Stick with my guide number because it's flat, not dished.

  10. #10
    Randy Moe's Avatar
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    Re: Using Sylvania Blue Dot #2 flashbulbs

    YES!

    I never used this stuff. i think I do have a reflector that has u-shapped mount that does slide down the tube, and now i remember when i took the habdle apart, it has exactly that.

    Very good Jac!

    This is awesome. Thanks!

    I also just got a peply to my WTB flashbugs ad, i cant type I am so excited


    Quote Originally Posted by Jac@stafford.net View Post
    Lucky you. Your flash handle (battery holder) has the 90 degree head adapter. Take it off! Voila, underneath is a screw base bulb holder. Just push the bulb down into the hole. Got another reflector? There is one that fits over the top, surrounding the top, leaving the hole for the bulb base.

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