The sources of information used for this website are :
Manufacturers themselves are not good sources of information. Very few give any specifications of the hotshoe interface, such as the trigger voltage, and in more recent years they have been inclined to state misleading values for their Guide Numbers. I have not approached any myself as this website concerns units no longer made, and many of these manufacturers are no longer in business, but others who have approached them tell of inconsistent, defensive, or vague advice. It seems we are not supposed to worry our heads about these things.
- Botzilla's huge list of flash trigger voltages, giving his own sources, here :
It has not been updated for many years (since 2005?) and while, in a sense, data on old flashgun units should not need updating, it has not been open to the submission of additional data to fill gaps - I know because I have tried with no response. It is also Canon oriented. Being concerned that the site might be abandoned was my prime motivation to create this one. The advice in the introduction not to worry and just buy a modern unit instead, is not re-assuring. The site also gives no context to the flashguns listed (eg age, Guide Number) - this was not its purpose of course, but in reading it I was intrigued by all those brands and model names and wanted to learn and add something about them.
- A Chinese website here with an unformatted list (in English) of about over 800 flashguns with their trigger voltages. Last updated in 2015.
- Numerous individual trigger voltage reports from internet forums.
- A dozen or so voltage measurements I have made myself.
- Information on Guide Numbers and exposure modes from old catalogues and brochures I own or which I have seen on the web.
- Flashgun manuals on M. Butkus library of camera instruction manuals.
- Pictures of cameras and flashguns found on the web, particularly ones for sale on Ebay, has enabled me to identify camera hotshoe layouts, and the Guide Numbers and exposure modes of many flashguns from views of the control panel.
- The circuit diagram Fig 1 on the Technicalities page is based on one in Lewis Loflin's website
- Technical information on some actual flashgun circuits from Sam's Strobe FAQ
- A Malaysian website in English language with detailed reviews of classic film cameras and a wealth of technical information. Discusses weak points as well as strong points. The internal navigation is not always easy to follow but this link is a good place to start for the cameras : Photography in Malaysia
- The Pentax K-Mount Page website for some detailed information on Pentax hotshoe connections. KMP