Flash guns

[thoughton]

Hard to tell what's going on from that description, eg what mode are you shooting in and what mode are the flashes set to? Im still inclined to think the PTTL pre flash is to blame. Can you post some examples with full exif data?

[ericmark]

OK more experiments. If I use a lens without any electric contacts internal flash fires slave A1 so there must be a pre-flash to set the focus. Tried turning off auto focus with electric lens on camera but still must activate pre-flash.

Fill in flash seems to be a problem in fully auto mode (green) it will not fire flash gun unless there is low light. I am told by others that with non dedicated flash guns it will not fire flash at all. Mine is part dedicated it has two contacts not the four used on modern ones but seems to work OK. It stops the spark sign flashing when charged and fires when required.

The camera speed does seem odd. The F stop will vary from f3.5 to f5.6 according to focal lenght. As one goes to wide angle which is f3.5 then the speed goes to 1/30 second. But as one zooms in the speed changes to 1/60 second. I will guess it's not to do with F stop but more to stop camera shake?

In the semi-auto mode (A) the speed is also odd it will let you reduce speed but not increase so your forced to use 1/30 second. Once in the Sv, Tv, Av or TAv modes it limits one to 1/180 second which is what I would expect as that's fastest speed where the shutter is fully open.

Because one needs to set the flash gun to the same aperture as camera for the sensor to work Av mode is of course the best option. although I have been using the manual and motor drive settings on the flash when using out doors as the sensor seems to give some odd results when there is no ceiling to reflect the light back onto the sensor.

Below is one of the results using out doors. Likely could have been improved by altering ISO but was in a hurry to catch bus.