Older flash units can damage modern digital cameras, as the strobe’s trigger voltage (the voltage discharged by the flash unit through the camera’s hotshoe contacts) can be outside the acceptable range for the camera. Modern flash units are designed to work with cameras containing electronic components, and have a trigger voltage that complies with the 24 V maximum of the ISO 10330 international standard. Older flash units designed for mechanical cameras can have a trigger voltage of hundreds of volts.
Unfortunately, Epson does not specify the maximum safe trigger voltage for its R-D1 camera, and the only mention of potential problems is on its website:
Please note when using flashes that they do not use high voltage, since the flash shoe of the R-D1 is not equipped for it.
As Epson does not manufacture flash units nor specifies any particular model for use with the R-D1, it seems logical to assume the ISO 10330 maximum of 24 V is the safe maximum voltage, though there is, of course, no guarantee that the logical choice is correct.
The Strobe Trigger Voltages web page lists the trigger voltage of a large number of flash units, both old and new. If your flash unit isn’t listed, you can measure the trigger voltage with a voltmeter: turn the flash unit on, let it charge up fully and measure the voltage between the positive contact (the centre pin on the unit’s hotshoe) and the negative (outer) contact.
If you want to use a flash gun with an excessive trigger voltage, the voltage can be reduced with a Wein Safe-Sync Hot Shoe to Hot Shoe High Voltage Sync Regulator.
Suggested flash units
The Leica flash units are an obvious choice for the R-D1, but are very basic (non-moveable head, low power, etc.) and poor value for money. I prefer to use Nikon units:
- Models from the SB-10 onwards have a safe trigger voltage of 6 V or lower.
- They are cheap and readily available.
- Although their TTL function is Nikon-specific and can’t be used with the R-D1, the auto and manual options are comprehensive.
The Nikon SB-30 is ideal for casual use when you want to keep bulk and weight to a minimum: it’s tiny and feather-light, but has exceptional auto and manual options for its size. It does have two cons, though: a fixed head and no sync socket. The SB-30 turns up on eBay at a low price quite often—presumably from sellers unaware that it is a modern unit only recently discontinued.
If you require a more powerful flash gun with more functions, the SB-24 or SB-26 is ideal. Unfortunately, although they’re easy to find on eBay, prices have gone up over recent years, as photographers have discovered how exceptional these units are owing to websites such as Strobist (e.g., Steal this flash). A cheaper alternative with a quirky rotating head is the Nikon SB-20 (Review: Nikon SB-20).
Sync cord polarity
The R-D1 has a polarised sync circuit. If the flash unit won’t fire and you’re using a studio power pack with a sync cord connector, try reversing the polarity of the connector.