In my post from Saturday, I explained how you can trigger remote flashes at shutter speeds that are above what your camera’s max. flash sync speed is. I thought what I was getting was High Speed Sync, but according to my buddy David Hobby it’s not quite the case. Here’s what David had to say about it:
What you are getting is not HSS, but rather a single pulse that is timed to last throughout the time the slip travels across your frame on a <250th speed. That is why you are only getting f4 at that ISO in that close.
It does work (no frame blackout) but you lose so much of the power of the flash (wasted on the blocked out part of the shutter) that it is pretty much a wash vs the CLS way. In fact, dollars to donuts I would bet you get less light via the “sledgehammer HSS” technique used here.
That said, it does apparently work, if not very efficiently. Kind like frying one of those geese with one of your radars does technically make it a microwave oven …
So what I set out to do next was compare the CyberSync method to traditional Nikon CLS and see how the two stacked up against each other with regards to power. Both methods prove to be very inefficient, but will work in a pinch if you get caught in a situation where your ambient is just too bright to knock down with shutter speed alone.
I shot these outside in early evening when the sky was still nice and bright. I metered the background at f5.6 @ 1/800th ISO200. I put an SB800 with only a diffusion dome on a lightstand, another on my D90, and connected the CyberSyncs. I set my shutter speed to 1/1000th to underexpose the background a bit. The light was 36″ away from my subjects (my daughter and her friend) whom I was able to convince to stand still for a couple minutes. The SB800 on the stand was set to full power and here’s what I got:
Much better. So now it was time to try out CLS. I disconnected the CyberSyncs and then put the SB800 on the lightstand in Remote and put the SB800 on my D90 in Master. I set the remote flash to Manual mode at full power. This was the result:
If you notice where the kids are in relation to the trees compared to the shots above, you will see that I actually had them standing CLOSER to the SB800 when using CLS and the shot was a little underexposed.
What’s the Take-Away?
Although the “Sledgehammer” method (as David called it) is very inefficient, it’s actually a little better than the CLS method. However, so much power is being wasted here that my NiMH batteries for my Speedlights hurt just thinking about me putting them through this kind of abuse.
To be very effective at all, you’d need to have two or three speedlights (at least, more if you wanted faster recycle times) and your shooting pace would be rather slow. It would work if you had no other options, but it isn’t really a “go-to” solution.