>My apologies for a misconception. Point taken. I was hoping >to use flash at high shutter speeds while having some >flexibility with aperture. I was using easy ISO, shutter speed >in excess of 1/1000th, ISO 100, with the variables being ISO >and aperture. I wanted to reduce those variables to aperture >alone. Clearly that is not feasible. I understand others want >this functionality as well, hence a solution to a desire. Not >a solution to something broken. > >Thanks and regards, > > >Victor > >My website: www.rakmilphotography.com
I understand your need. You can come close to your desired solution by simply using Regular TTL (Not TTL-BL), Auto FP High Speed Sync, ISO to whatever you want, Camera Manual mode and set the shutter on 1/1000 and the aperture to whatever you want.
Then, the Regular TTL flash system will compute the correct flash power for that combination. This will not work for TTL-BL.
The Regular TTL flash system will compute the correct flash power for whatever combination of ISO, Aperture, and Shutter you chose.
However, since it is Regular TTL, it will not take the ambient into consideration, so you must choose settings that will make a dark image without the flash. If you want to allow some ambient into the shot, then you have to reduce the FEC by around 1 ev.
And it's up to you to make sure you don't pick a combination that will require more flash power than you have. Remember that in High Speed Sync mode, the maximum flash power is cut approzimately in half from normal flash sync.