A lovely and fully working vintage Cobra Auto Thyristor flashgun — tested both on the bench and on camera. The thyristor circuit is the key feature here: rather than discharging the full capacitor on every shot, the thyristor automatically measures the reflected light from the subject and cuts the flash the moment correct exposure is reached, conserving the remaining charge. The result is significantly faster recycling times and much better battery life compared to a standard manual flashgun — a genuinely useful piece of kit for film photographers.

Condition

• Overall: Very good condition.
• Function: Fully working — tested on bench and camera.
• Cosmetic: A couple of small marks — nothing significant.
• Power: Requires 4 AA batteries [not included].

Provenance

• Maker: Cobra — a well-regarded brand of photographic accessories and flashguns, widely used by amateur and semi-professional photographers throughout the 1970s and 80s. Cobra flashguns were known for their reliability and value.
• Technology: Thyristor auto flash — the thyristor automatic exposure system was a significant advance over earlier manual flashguns, using a sensor to measure reflected light and quench the flash at the correct exposure point. This conserves battery charge and dramatically reduces recycling time between shots.
• Compatibility: Hot shoe and PC sync connection — compatible with a wide range of 35mm film cameras.
• Appeal: A practical and usable vintage flashgun for film photographers — the thyristor auto system makes this a genuinely capable accessory rather than just a display piece.