Interesting Simon - a good read. Some questions / thoughts:
Method #6 you say "Set your shutter speed to somewhere above your max flash sync speed, say 1/125. This will freeze movement and allow you to stop it down a bit if you need to." I would be careful using numerical indicators such as higher/lower/above/below with shutter speeds - they can be confusing for readers - instead say slower or faster... and I presume you actually meant to say set your shutter speed to somewhere BELOW your max flash sync speed
- hence the reason I think slower is just less confusing). It might be worth reminding the reader that with a reasonable amount of flash, that will be freezing movement of the subject, irrespective of the shutter speed (although with a very slow shutter speed you may be letting so much ambient in, the flash has to have minimal effect...)
Method #7 you say "The aperture should give sufficient sharpness throughout the scene but is mainly used to control the exposure of the ambient light". I agree with the first bit, but aperture (along with ISO) affects the exposure of ALL light - i.e. flash and ambient equally. Stop down either of these and the image will get darker uniformly - both flash subject and background. I would argue that setting the aperture for the required depth of field is the first (and in many cases, only) consideration with that part of the exposure triangle unless you're really getting into really high ISO & too slow s/s territory.
Perhaps it is worth setting out for the reader that in your setup, they have five primary controls of exposure elements:
1. shutter speed - affects ambient light exposure only, but at slow settings also the amount of motion-blur in the non-flash area (relevant if windy?)
2. aperture - affects all light exposure and changes the depth of field - for this reason I would use this to set DOF as required rather than tweaking exposure
3. ISO sensitivity - affects all light exposure and eventually reduces quality more the higher you push it
4. flash power - obviously only affects subject exposure - i.e. the added quantity of light on the subject within the flash area
5. flash distance from subject - only affects subject exposure but also has a marked impact on the type and spread (i.e. quality) of light falling on the subject because of the relative size of light source and the inverse square law
Of course, there are still plenty more variables to play with such as modifiers and flash zoom settings which will all affect the spread and quality of light coming from the flash!
I'm still a novice to all this though, so I could be talking utter mince. But that's my understanding of the theory behind it?
