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  1. #11

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    The seller sheet I posted pre-dates the M-25B and M3.
    I have a box of:
    Sylvania NEW! Zirconium-Filled M-25B flash bulbs.
    These must have come out in the late 1950s after this publication.
    The M-25B has the small S.C Min. base that the M-2 has.
    The box states that the total light output is 8,500 Lumen Seconds for the M-25B.
    It also states "Set Synchronizer for 15 milliseconds"
    This is fairly close to the Press 25B with a total output of 9,000 Lumen Seconds.

    I assume that the M-25B is similar to the GE M5B.

  2. #12

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    Dug further into my collection and found a similar age box of clear M-25 bulbs.
    They are rated at 16,000 Lumen Seconds.
    Fairly Similar to the Press 25 rated at 20,000 Lumen Seconds.

  3. #13

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    Looking further into it, GE must have changed the classification of the M5s at some point. I have a box of M5s that mention that they are class M and will only work with M-sync (or a slow shutter). I also found a newer box of 6Bs that recommend AG-1B, M3B, or M5B to replace the bayonet-base bulbs, meaning at some point the M5 must have become a brighter version of the M3.
    "Panic not my child, the Great Yellow Father has your hand"--Larry Dressler

  4. #14

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    It looks like the M3 bulb came out in 1963

    This information in an April 1963 Article in Popular Science.

    “Westinghouse is introducing ...The M3 will take the place of the No. 6, M5 and M25 bulbs...Zirconium filling in the new bulb comes to a high intensity level (twice the output of aluminum) quickly and maintains it for a long time.... It can be used for most focal-plane shutters, all leaf-type shutters”

    Now if anyone had a graph of the light output of the M3 that they could post that would be great. We could compare it to the 1957 Sylvania dealer sheets I posted we would have a good idea of how it stacked up to the FP-26 bulb (quite similar to the the GE No. 6).

  5. #15

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    The GE 6B (LEFT) and the Sylvania FP 26B (RIGHT) were similar in terms of light output. They were not identical however. See Photo. In day to day use you could most likely interchange them and never see the difference in the prints. So in that respect you could say there were the same.

    Note in the Sylvania Data Sheet posted above there is a table with a column heading titled : Nearist Comparable Bulb (Other Mft.) There the 6 B is listed as being roughly equal to the FP 26B
    Attached Thumbnails Attached Thumbnails GE 6B vs Sylvania FP 26B.jpg  
    Last edited by brianmquinn; 03-24-2011 at 10:02 PM. Click to view previous post history.

  6. #16

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    Help please!!

    Hi, does anyone know if the midget size bulb(like M25) will be fit ok into a flash unit that usually uses bulb like P25 or GE 5 or another way round. Are they having same size in base and can they interchange with each other?

    Thanks!

  7. #17

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    Quote Originally Posted by windly9 View Post
    Hi, does anyone know if the midget size bulb(like M25) will be fit ok into a flash unit that usually uses bulb like P25 or GE 5 or another way round. Are they having same size in base and can they interchange with each other?

    Thanks!
    No. The base of the M-25 is smaller and different. There are adapters to use M series bulbs in flash units designed for #5 type bulbs. Also the #5 or Press 25 bulbs will not work in the M series flash guns. Press 25 or GE #5 bulbs were designed to work with five inch reflectors and the M series bulbs were for a three inch reflector. Changing reflector size can make a difference in guide number.
    Dave

    "She's always out making pictures, She's always out making scenes.
    She's always out the window, When it comes to making Dreams.

    It's all mixed up, It's all mixed up, It's all mixed up."

    From It's All Mixed Up by The Cars

  8. #18

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    Moplar_guy is almost 100% correct. I do know of one exception however. Kodak used to make a flash gun with the name of Kodalight IV Flasholder. It has a 4 inch reflector and will take a bulb of the #5 or Press 25 size just as easily as an M2, M3, M5 or M25 bulb. However it was a pin connector for Kodak cameras, not a near universal hot shoe mount. Perhaps Kodak (or someone else) made a version that would connect to a PC socket or hot shoe. I just have never seen one like that.

    As Moplar_guy pointed out smaller bulbs worked best with a smaller reflector and larger ones with a larger reflector. That is likely why Kodak picked a mid point 4 inch reflector for this dual use flash gun.
    Last edited by brianmquinn; 03-31-2011 at 08:57 PM. Click to view previous post history.

  9. #19

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    Here is a photo of the guide number info. on an old* box of GE M2 bulbs. See the note about the reduced guide number when using an adapter for this small bulb when used in a flash made for the larger No. 5 or Press 25 bulbs. For those not skilled at guide number calculations; you loose about one stop of light with an adapter.

    *Back before they changed the film speed rating system and Tri-X was only rated at 200. If anyone knows when they revised the system by how they set film speed and any details please let me know. If nothing else it will help me date this box of flashbulbs.
    Attached Thumbnails Attached Thumbnails GE PowerMite M2 Flashbulb Guide number.jpg  
    Last edited by brianmquinn; 03-31-2011 at 09:15 PM. Click to view previous post history.

  10. #20

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    continue...

    What about these:

    1. Does it mean that if the flash unit can take GE No. 5 , then it surely can take Sylvania Press 25 or other bulbs that has boyanet base?

    2. What is the different between M2, M3 or M25?

    3. Why don't we just use Blue bulb since it can be used when taking both B&W and color photo. Why is clear bulb needed since it is only used on taking B&W?

    Thanks guys!
    Last edited by windly9; 04-02-2011 at 08:07 AM. Click to view previous post history.

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