Buying Strobes? Do you know the Flash Duration? (How to Stop Action in Photography)

The following question came recently:

"Kevin,
I am a big fan of your work after seeing you on strobist, I am now doing quite a bit of adventure oriented advertising photography. I hope you can answer one question for me.... I am deciding between the Elinchrom Ranger RX Speed AS pack with "S" freelight head or Ranger RX pack with "A" freelight head. CAN THE "S" FREEZE ACTION FAIRLY WELL OR DO I HAVE TO GO WITH THE "A"? I understand you are very busy but hope you can lay a little info on me.
I use Canon 5d II, 16-35 II, 24-105, 70-200 f4. pocketwizard plus ii's
Thanks!"

This is a great question because it addresses one of the most important, yet overlooked items to consider when buying a new set of strobes, especially for sports photography, that of Flash Duration.  The key difference between the two heads in question is the flash duration, the "A" head being twice as fast as the "S" head.  Flash duration, just like shutter speed, is measured in fractions of a second and becomes your action stopping measurement when working in low light or dark (studio) situations. Typically, you want the shortest/fastest flash duration possible, just like you would want the fastest shutter speed possible when shooting and trying to stop action.

To visualize this, find a room in your house that you can turn completely dark (no ambient light leaking in).  Put your camera on a tripod and open your shutter for 30 seconds.  Now, let's say during your exposure, the fastest man in the world, Usain Bolt, runs in front of your lens and just as he passes by, you fire your strobe.  Will he be in focus, blurry or a combination of the two?  Remember, your shutter is open for 30 seconds, so wouldn't he just be a blurry abstract blob in the final image?  The truth of the matter, is that the action freezes based entirely upon your strobe (remember no ambient light) and the accompanying flash duration of that strobe, or in other words, how QUICKLY your strobe goes on and then off.  So if your strobes flash duration is 1/125th of a second, Usain is going to be blurry!  So what is your strobes flash duration?  In the case of an Elinchrom Ranger it is a combination of which head, pack and power setting is used.

If I were shooting Mr. Bolt in a studio with my Ranger AS Speed pack, A head and Full power on the B channel (366 w/s), the absolute best (shortest) flash duration I could achieve would be 1/1700th of a second, plenty fast to stop the action (see my note on using the t.1 rating instead of what the mfg suggested t.5).   However, with the same settings but switching to the "S head" my results would be 1/850th of a second.  Now, what if I needed full power from my pack (1100 w/s)?  Note the chart above with 1 A head @ Full power = 1/2300 s and 1 S head @ Full power = 1/1250 s.  For the A head, my action stopping power has been reduced from 1/1700th to 1/766th and S head from 1/850th to 1/400th, which starts to creep into the blurry zone for action stuff on the S head.  Lower power settings would result in an even slower duration and more chance for motion blur.

Skiing photograph shot during the SLC shootout. Skier: Jason West.  4 strobes used in total: 2 Elinchrom Ranger RX Speed AS Packs, 3 "A" heads and 1 Canon 580EXII fired via Skyports.  Lighting set-up here The action in this shot is entirely stopped by the strobes (roughly 1/2000th of a second flash duration).

Phew...so, what does all of this mean in the real world and why is it important?  If you are using strobes while shooting ANYTHING moving, then just like knowing what shutter speed to pick to create a sharp, crisp image, you should also know what flash duration you'll be getting from your strobe:

-hummingbird feeding
-gymnast during a floor exercise
-outdoor portrait of model on a windy day (blowing hair)
-pouring a bottle of Coca-cola into a glass for a product shot
-cyclist descending Cormet de Roselend during the Tour de France


IN SUMMARY:
1.  Flash duration stops the action and becomes your shutter speed (in low-light and dark settings)
2.  Flash duration changes (typically is fastest at full power)- check mfg specs
3.  If your strobe manufacturer uses the t.5 number, divide by 3 for the true stopping power of your flash.

So, what's the answer to the question?  For the most flexibility stopping motion, get the "A" head.  This is one of the main reasons I chose the Elinchrom system because most of their lights have very fast flash durations at a reasonable price.  However, just like buying any piece of equipment, consider why you need the faster flash duration head and how it will fit into your work as a photographer and buy what fits your needs.

And one final CURVE BALL to end on:  If you shoot location work during daylight (much of what I do) then your true stopping power becomes a combination of your cameras sync speed and your strobes flash duration OR worse yet, entirely dependent on your cameras sync speed.  In the next blog post we'll discuss using strobes with ambient light, on-location.

-Kevin Winzeler
Advertising and Commercial Photographer based in Salt Lake City, Utah
Tags:  Elinchrom, Ranger RX Speed AS, Commercial Photographers

5D Mark II shoots the Season Finale of "House". Greg Yaitanes interview.

Phillip Bloom interviews the Director and producer of of the hit TV series House, Greg Yaitanes, in this interview.  The fact that the director of a major TV series decides to shoot it's season finale (not just parts of an episode) is unreal.  As photographers and film makers, we have access to an unbelievable number of tools to tell and share stories.  Exciting times ahead folks!

It sounds like the Canon primes won on set along with a couple of zooms to ease the transition of shooting different focal lengths.  Of note were the 50 f/1.2, 85 f/1.2, 100mm Macro (used in the opening sequence below) and 70-200 f/2.8 II.

There's a good discussion happening over at Cinema 5D on the topic and hopefully we'll see some behind the scenes footage and further discussion soon.

If you missed the show this week, download an HD version at the iTunes store.

-Kevin
---
Commercial and Advertising Photographer

Advanced camera panning techniques (Sports and Action photography)

When we think of sports photography, usually we think of shooting at the highest shutter speed possible and wide open apertures in order to stop the subject dead in his/her tracks.  The sharper the image, the better, right?  Let's talk about breaking this rule for a minute and working to capture more of a sense of motion in your images.  How do you translate the feeling of a cyclist racing across the asphalt at 30mph?  How about the movement of a propeller as an airplane leaves the ground at take-off?  Or a sail boat piercing it's way through an open ocean?  Or what about a skier tunneling through three feet of freshly fallen snow?  One way to create movement in our imagery is through the use of slow shutter speeds and panning the camera.  As a commercial photographer, I'm constantly striving to create the most intriguing and compelling photographs.  Of the many techniques available to photographers, panning and the use of slow shutter speeds is an excellent tool to add movement and energy when shooting action.
Skiing image: panning at 1/30th of a second

The easiest way to practice this technique is to pick up the camera, walk out of your front door and point the camera at moving cars.  You can experiment with different shutter speeds, backgrounds and subjects this way.  To take panning to the next level, the trick is to get the camera into a position that it can move at the same speed as your subject.

Road cycling image: panning at 1/20th of a second from the back of a van.

Some other points to consider when panning:

1) Pick the important elements to keep sharp:
What are the important elements to keep sharp in the final image?  If I'm shooting people, I generally want head and facial features sharp.  If it's a commercial shoot, keeping logos, product names or other elements we are advertising is also critical.

2) Move with your subject:
Once you have the location and subject matter, next decide on your composition.  The easiest way to explore the technique of panning is to move the camera parallel to your subject as they ride, ski, swim, walk past you.  For example, during the 2006 Tour de France, I captured this image of cyclist, David Millar during the prologue stage of the tour.  And a few months ago during the Salt Lake Shootout, I captured this skiing photograph with roughly the same technique.  However, if you're working in a more controlled environment, try getting into a position where you can keep the camera still and move with the subject.  Whether it be a bike, motorcycle, car or other rig, try the camera into a position is moving at the same speed and direction as the subject.  For the following image, I wanted a head-on perspective and so we jumped in the back of a mini-van and with the tailgate up, started shooting.   I love the gritty feel of getting the camera close to the moving pavement, while keeping the rider and bike in focus.

3) Choose your shutter speed.
Panning requires a steady hand and experimentation with your shutter speed.  For example, when shooting a cyclist, I'll start in the 1/25th of a second range and move up or down from there to get the right blend of motion and sharpness.   Also, keep in mind your background colors when choosing your shutter speed to create either something that's recognizeable or completely blurred giving an ethereal and abstract feel.

Lifestyle shoot: Panning at 1/5th of a second (strobed w/ Elinchrom Ranger)

Lastly:

1. Use ND Filters.  If you're shooting on a sunny day, throw a neutral density filter or polarizer on your lens to bring your exposure back to 1/30th of a second (or whatever shutter speed you decide on).  As a LAST resort if you can drop your iso to 50 and crank your aperture to f/22, but make sure your sensor is clean!
2. Bring lot's of memory.  We shot roughly 300 images of one athlete in the span of 2 minutes or so on the 5D Mark II (3.9 FPS).  We had roughly 10-15 keepers.
3. Safety first.  If you are hanging off or a motorcycle or out of the back of a van, make sure to communicate to everyone involved.  You, the driver and the athlete need to be on the same page.  The last thing you want is for the driver to suddenly hit the brakes while your cyclist is trailing 3 feet behind at 30 MPH.  Keep it safe.

What are some of your techniques for panning?  Let's hear it.  Next, we'll talk about panning with the use of strobes (big and small).

-Kevin

More behind the scenes videos and photography

Inspiring Documentary: Up There

A few quick thoughts from the documentary "Up There".

First, I hope in addition to shooting a ton of photographs lately, that you are also experimenting with video on your DSLR.  As a commercial photographer often working with people, I can say that the number one benefit from shooting and understanding motion and film has been learning to direct people.  Film also helps me to think in terms of story telling with my photography, which I worked on more this past weekend while photographing Ironman, St. George, Utah (photos coming soon).

Second, both the artists in the story as well as the artist, Malcolm Murray telling the story inspire me to be patient and continuously improve my craft as a photographer.  I love how these folks talk about the process of learning and the time and sacrifice involved in becoming an artist in their field.  In this fast paced world, where truck loads of free information are available at our finger tips, we can at times be a bit too anxious.  Amazing doesn't happen in minutes, but rather it takes a long time and sometimes a lifetime.  Let's step back and appreciate the photographers that have paved the way for us, as well as steadily improve as artists.  Patience is a virtue I believe...

Third, shoot photos and stories you are passionate about.  This story is told with a sense of pride and passion.

-Kevin