martinfisherphoto wrote:
Just so ya know you don't need HSS to freeze motion with a flash.. In fact, the Lower the Power setting on the flash the higher the speed the camera can freeze. Now that's Assuming the exposure is correct and the flash is providing the light for the exposure.
HSS allows the use of a higher shutter speed. The light from the flash, in HSS mode, is essentially continuous. But shutter speed is limited to 1/8000 of a second, and the actual amount of light from the flash is very low and is used only as fill light.
The low power settings on a flash can be faster than 1/8000, but then the camera's shutter speed is limited to probably 1/250 of a second depending on the camera's X-sync speed. Even at ISO 100 and stopping down to f/16 that can leave too much ambient light to eliminate blur on a hummingbird's wings.
martinfisherphoto wrote:
I would try lowing your ISO and closing down your aperture to the point your flashes provide the correct amount of light for the exposure.
Read article from member Sterrill, just above yours, where he cannot get enough light using 4 flash units on a bright sunlit day!
The speed of a typical speedlight will be slower than 1/10000 second at 1/16 power and about that or faster at 1/32 power. Such flash unit's maximum output is about 80 Ws, so getting a flash duration of 1/10000 with 4 units means shooting with a total flash power of about 10 Ws.
Roughly the same effect would be had by using the flash units in HSS mode and shooting with a shutter speed of 1/8000. The flash provides fill light and does not stop motion.
But consider another method, and use the right kind of a studio strobe. Paul C. Buff Einstein models in "Action" mode have a 1/10000 second duration when set to 40 Ws, so just one such strobe would have 4 times the light power of the 4 speedlights. Obviously either 2 or 4 units would provide even greater amounts of light, probably sufficiently overcoming the ambient sunlight.
Of course hummingbirds are a worst case scenario that is far more demanding than is the typical camera shake from hand holding at macro magnifications. HSS is more likely to work if for no other reason than the flash can be much closer to the subject and thus provide more light. A studio strobe will provide better light at a short enough interval but it is not as mobile when chasing insects.
Again, all of these require the photographer be aware of the ups and downs with each, and be able to choose the right method for any given shoot.