Are you looking for display material or actually shooting with the CEYOO ?
In the hey-day of the CEYOO and the III-g / early M cameras, bayonet-base bulbs would have been most common among amateur photogs, for cost / space reasons .
Now, if you're trying to shoot flash photos in the 21st Century with this rig, read-on, MacDuff... 😉
If I remember correctly ( all my Leitz blitzlichthalter are in storage... 😉 ),
The CEYOO will take the following:
"Edison, medium screw base"
"Bayonet-base" - with adapter "mast" furnished with CEYOO - places the shorter bayonet-base bulbs at the optical center of the reflector.
That's it for the official CEYOO as it came from E. Leitz.
But wait, there's more:
After the introduction of the "M" series bulbs and then the all-glass AG-1 bulbs, various suppliers came-up with adapters to use these bulbs in a standard "bayonet socket".
Dralowid posted a photo of the bayonet adapter "slug" to use the all-glass PF-1 bulbs, also known as "Vacu"... the "bayonet to M" is very similar, except that the center of the adapter is configured to accept the M-base bulbs.
I think somewhere, I have AG-1 > M and /or AG-1 > Bayonet adapters...
So... it is possible to fit almost any type of flash-bulb into a CEYOO and make it light.
I used this trick with a 1930's black & nickel Leitz "blitzlichthalter" flash-gun and a 1934 Leica black III which had been fitted with a PC flash connection ( fixed sync ), and using the "M to bayonet adapter slug", used M-3-B bulbs. It worked well, except that most of my pics were over-exposed. That's an operator's error. 😱
I went with using M-type bulbs, as I have quite a supply of them.
Now, as far as getting the correct synchronization goes, that is a little more complex.
Does the III-g have an adjustable flash-sync dial ? If so, you can use almost any flash=bulb that will fit in the gun.
Be forewarned if you decide to try a big "Wabash" type Edison screw-base "Press" bulb - you might "cook" your subjects ! 😱 😎
