High Speed Sync Hack

Sports photographers wanting to use flash photography have one common enemy, camera/flash sync speed.

There are times when the photographer wants to reveal the subject with flash.  The problem is the subject is moving too fast for the very limiting shutter speed that photographers are forced to use when a flash is in use.  The majority of today's dSLRs have maximum sync speeds in the neighbourhood of 1/200th or 1/250th of a second.  These are not what I would call action freezing shutter speeds.

What do you do when you want to blend ambient light and flash when your subject requires faster shutter speeds?  Flash durations can be fast enough, but the ambient light continues to spill into the frame the entire time that the shutter remains open.  The bane of sports photographers everywhere, ghosting.

Continuous light is the answer and top-of-the-line flashes can do it.  Instead of triggering the flash while the shutter is open (x-sync), FP/HSS technology begins pulsing the flash before the shutter opens and continues to do so until the second shutter recovers the sensor.  The result is a form of continuous light.  The trade off is these pulses are very weak.

It's time to introduce the high speed sync hack.  It's not new.  Google it and you'll find links that date back a few years.  What you won't find is a decent explanation on how to use it effectively.  That is why I am writing this piece.

What you need is a flash capable of FP/HSS and a method of connecting a radio trigger to send the early signal to other flashes/strobes off camera.  The FP/HSS capable flash will be in the hotshoe, so either the flash or the camera is going to need to have a PC terminal to connect your trigger to.  The key to the hack is using that early trigger signal and sending it via radio to other flashes that are set to full dump, not wimpy little pulses.  If the flash duration is longer than the shutter speed, you have continuous light!

Here is what I do.  I put my SB-800 or SB-900 in the hotshoe.  I then connect my flash, PC terminal to mini phone jack to Pocket Wizard Plus II.  The result is the flash trigger signal goes out before the shutter begins it's travel across the focal plane.

Nikon SB-900 with Pocket Wizard Plus Transmitter mounted in the 'hack' formation

Off camera I configure my radio triggers according to normal convention, with one exception, the flash must be in manual mode and set to full power.  The necessity is the long flash duration.

The magic behind all of this is that I can now use any fast shutter speed and there will be flash and ambient light for the entire shutter duration.  No ghosting!

As long winded as my introduction has been, this is where I tell you how to use it.  Since your shutter speed is faster than the actual flash duration you are not using all of the light emitted from the flash.  As a result of not using the entire flash pulse, light meters will not produce the proper reading.  All those fancy Guide Number calculators that are built into your flash are also no longer accurate.  You need to build your own GN tables for every shutter speed.

Here is what I did.  I placed my off camera flash at a measured 10' from my grey card.  I set my camera up so that it framed the grey card only.  At each shutter speed, I adjusted the aperture to place that histogram spike as dead centre as possible.  The result was aperture multiplied by 10' equaled the GN for that shutter speed.

At ISO 200 and my flash head zoomed to 85mm, here are my results.  You can find this chart typed into my BlackBerry, it's with me all the time.

1/320th = GN 160
1/400th = GN 140
1/500th = GN 140
1/640th = GN 140
1/800th = GN 130
1/1000th = GN 110
1/1250th = GN 110
1/1600th = GN 100
1/2000th = GN 90
1/2500th = GN 90
1/3200th = GN 80
1/4000th = GN 71
1/5000th = GN 63
1/6400th = GN 56
1/8000th = GN 50

For comparison, full power in FP mode at 1/1600th of a second has only enough output for GN40 instead of GN100 using the hack.  That's huge!

What are you going to do with all that extra power?

Lightning

After what started out as a fairly slow summer has accelerated into a lot of shooting over the last month.  I will slowly release some recent shoots as my clients get a chance at first release.

Last night I did some personal shooting, something I really love.  Lightning.

Ever since I was a little kid, I can remember staring out the window watching lightning storms.  Once, I got older, I would drive down to the beach just to see a storm roll in off Lake Huron.  Now, with the photo bug, it is almost pathological.  Last night, my wife kicked me out the door to go shoot.  I might not be that pleasant to be around when I am "missing" a good storm???

The interesting thing about last night was it didn't look that impressive on the radar, but I could hear the constant rumble of thunder and that inspired me to give it a try.  I am glad I did.  I had a blast!!!

More often than not (with my limited experience) good electrical storms come in off the lake like a wave.    A straight line front rolling over land with short burst of intense weather.  Last night was different, it was more like a streamer.  A line of rain that kept coming off the lake.  This was good.  This gave me more time to set up.

Because I was not originally inspired by the radar, I was off to a slow start and wasn't sure where I wanted to be to be ahead of the storm.  Down by the lake was out of the question.  It was already happening there.  So, I drove inland and after about 20 min I was finally ahead of it.  But, this isn't where I would normally go.  I wasn't sure what I was going to us for a foreground.  Driving aimlessly, all of a sudden I found a likely spot.

Capturing an image of a lightning bolt is actually pretty easy.  A good place to start is 30" with an aperture of f/5.6 and ISO 200.  A stop either side of there depending on how close the storm is will put you pretty close.

The neat thing is that lightning exposes itself.  Leave the shutter open as long as you want, each successive bolt will appear out of the darkness of your frame.

Generally, a lightning bolt on it's own is not that interesting.  Give it a recognizable foreground and you have magic.  City skylines, iconic landmarks and the like all work well.

What to bring: a tripod, a raincoat (for the camera), a flashlight (if you can't operate all your functions in the dark), a smart phone to keep checking to local radar and where the storm is moving, and a lens of your choice.  I use my 70-200mm most often, but have used my 300mm and my 20mm.

Finally, please remember to use some common sense.  Choose your location carefully.  Don't stand in the middle of a field.  Don't stand under the tallest tree.  Don't stay at your location until the storm is right on top of you.  You might not like the result.

Nikon D3 w/ 70-200mm @70mm - ISO 200, f/5.6, 30"  -1 stop applied in RAW conversion

Nikon D3 w/ 70-200mm @70mm - ISO 200, f/5.6, 30"  

Nikon D3 w/ 70-200mm @70mm - ISO 200, f/5.6, 30"  -2 stops applied in RAW conversion