I have an external flash. Osram C250 studio, it is over 20 years old I used to use it with my old SLR ,but it work(ed) with the SX20 as well. I`ve used it once or twice in the past (with the SX20) ,but when I tried to do so today it didn`t work for me. I checked the flash with a different camera and everything was alright. The camera detects the flash ,but doesn`t fire it. Has anybody encountered a similar problem,or does anybody know how I can fix it. I can`t see a reasonable explanation to it working with the SX20 yesterday and not doing so today. And due to the flash being OK ,I`m left with a problem with the camera.