300D with Yongnuo YN565EX II not working

Stephen P M Brown wrote:

I have tried manual mode on the flash and it still will not fire.

Do you mean the camera in manual mode or the flash in manual mode? Try setting the camera to manual mode ISO 100, f/8 and 1/100th then set the flash to manual mode full power (probably the default when you go into manual mode). Then see if this allows the flash to fire.

Further note of interest: when I half press the camera trigger the flash lights the scene with a cross grid of red light, ie: you can see the subject illuminated by them as if you were shinning a red led torch beam. Does that make sense?

That is the auto focus assist light. It makes it easier for the camera's auto focus system in low light (the sort of situation you would expect to use a flash).

I have a couple of old 35mm film Pentax cameras around, if the flash were working correctly would a 1980s Pentax MX be capable of firing the flash, as a test?

Should do with the flash set in it's manual mode. Set the shutter speed to 1/60th (MX X-sync speed) just to be sure.

It must be obvious by now I have no clue about external flash guns. I have never in 30+ years of photography used anything other than built-in pop-up flashes or those old-style one-time use flash bulbs.

Thanks.

I suspect it is either a breakdown in communications between the 300D and the YN565EX II (lack of backwards compatibility with the old E-TTL metering system) or a faulty flash. It is worth checking the reviews on places like Amazon especially the one star ones to see if other people have seen similar behaviour (also check the original 565EX reviews).

It might be a good idea to try contacting the supplier or Yongnuo directly to see if the 300D is a compatible camera.

Ian