Old flashes on new cameras

Having recently bought a battered but fixable Canon 400D for the price of an Xbox game, I repaired the memory card fault and found that the built-in popup flash wasn't working properly. It would only fire when at the very start of its throw - when fully up, it didn't want to do its thing. Since I couldn't be bothered to pull it to bits again, I decided to buy an external flash...it's more flexible anyway. Photos and electronic geekery after the jump!



One trip to Jessops decided that a new fully automatic flash was well out of my price range. Meh. There's loads of old manual ones on Ebay though - they won't talk or listen to E-TTL, so the camera can't tell it what power to fire at, nor can the flashfun fire off a metering or whether it's charged and ready to fire, amongst other things. All it does is close two contacts on the hot shoe electronically with an SCR to signal the flash to flash. Considering the price though, if you pick carefully and are happy with experimenting, it's a cheap way to get an off-camera flash!

However, some flashes have a very high open circuit trigger voltage - this is voltage which sits between the trigger pins on its hot shoe. Fine for old mechanical cameras which close the circuit mechanically, not so fine for the sensitive guts of an electronic film or digital camera. I haven't found a definite figure, but 6 volts seems to be the lowest figure, although some sources say 250v.

Anyway, I found a Cobra D650 on eBay for £10, which has a trigger voltage of 5.5v and even came with an off-camera handle and cord.

Flash with handy handle

LCD panel

Works great, but although it's got a fancy LCD panel on the back, it's little more than a glorified flash power lookup table. Changing the aperture and ISO simply displays a different distance, based on what flash power you've selected using the sliding switch. However, it does have a little photocell on the front for the automatic mode, but given the viewing angle of the photocell's lens, it's hardly accurate.

Still, this thing has got some great product shots so far for a tenner. Sweet.