LATEST FEATURE: On Assignment: Ben Lurye

Friday, June 01, 2007

Hacking Your Camera's Sync Speed, Pt. 2

NOTE: This is the second of a 2-part series. The first part, which was about exploiting electronic shutters, is here. Today's post is about gaining power through partial-frame syncing.
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We recently lucked into a good deal on a used Trek MT60 mountain bike for my son Ben. We are big believers in buying better quality used, rather than cheaper-made stuff new. And I am proud that my 6-year-old is already choosing quality and value over shiny, cheap and new.

But a new bike, even if it is not really new, means doing a picture of him on it to email down to Nana and Papa Ken.

I shot a typical, quickie two-light setup. The first light was the sun, from behind and over Ben's camera right shoulder. The second was an SB-26 on a stand at camera left. It's easy to balance with the sun when shooting with a small flash at close range. And even at 1/4 power on the SB-26 there was plenty of off-camera fill at 1/250th of a sec.

But to raise that shutter speed even more, you have to try a little partial-frame syncing. This is a technique in which you only have the flash lighting part of your frame, with the trade-off being higher sync speeds.

As with the electronic shutter trick, you'll have to fool your camera into not knowing that there is a flash up top. Check back on part one for the how-to info. (Basically, it means no on-camera flash unless you insulate the TTL contacts, and no use of a TTL off-camera cord. Anything else - PC cord, remotes, etc, is cool.)

To give you an idea of how it works I set up an SB-26 on a stand, aimed at the wall, and started playing with the shutter on my D2Xs, which nominally syncs at 1/250th of a sec.

Here we are at 1/250th. No surprises here. The camera is supposed to sync at 1/250th and it does, with no blocked areas.

But what happens as we take a walk up the shutter speed scale?

As you can see, 1/320th is almost totally synched. That's because there is a little margin for error built into the system. But as we go up higher, you can see that there is still some flash-lit compositional room in which to play. And I frequently make use of higher speed by composing so the lit part of my subject is in the band of the frame that gets the partial sync.

Interestingly, you'll note that in this test the 1/640th test frame shows more sync area than the 1/500th. There is some variability in this technique from frame to frame, and you should allow for a little bit of a fudge factor when composing.

On my camera, the good band is at the bottom of the frame when held in a normal, horizontal position. Your camera may be different, due to different shutter designs, so you'll wanna check.

With a little compositional planning, I can comfortably sync up to 1/1000th and still get some good, usable real estate for my flash. Mind you, the electronic shutter trick is better as it gives you full sync. And the focal plane flash thing rocks if your gear supports it. But to some degree, this trick works with most any camera and flash. So you can always fall back on it.

You might think that a half-frame of flash-lit area is useless. But remember that in a high-speed sync situation, you are almost certainly basing your exposure on the ambient (even if you have knocked it down a stop) and lighting your subject somewhere in the frame.

It is easier than you think to pull this off when you need to raise your shutter speed, open your aperture and make your flash more powerful. The ability to overpower the sun in mid-afternoon is a cool thing.

For instance, if I am shooting BMX bikers going over jumps, I would light the area where they hang in the air and shoot at 1/1000th of a sec with my camera held upside down. Remember, my sweet spot is on the bottom of the frame.

If that sounds too acrobatic for you, try it. If you have a vertical release, it is cake. Really.

As an example, here is Ben shot at a 500th of a sec, which is a full stop past my sync speed. I have the flash zoomed to just light him from up top. As you can see, he syncs fine in the right hand composition, but not when he is on the left.

I could easily reverse this by rotating the camera to the alternative vertical orientation, i.e. trigger finger on the bottom rather than the top. And note that you cannot see the sync line, as the exposure is based on the (underexposed) ambient light.

Sure, you may have to jump through some compositional hoops with this trick. But it gives you the ability to really nuke daylight when you have to. All you have to do is try a bit of planning with your composition.

And you do not have to spring for a focal-plane flash setup or a camera with an electronic shutter. Which leaves more money for used bikes.


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17 Comments:

Blogger Jacob said...

David,

Interesting that you just posted this today.

I was shooting a corporate event yesterday in a large auditorium. I had two SB-28's on stands on either side of the venue, cross lighting the speaker on center stage (even trickier was that they had a projection screen pulled down that I *could* have used to bounce off and effectively back-lit him with the second strobe. He wandered around too much to use that though... and I'll fess up - I didn't think about it until it was too late).

I'm shooting with a Canon 30D, and as we've discovered, you can't push it much past 1/250th, or you get the dreaded black line. There were a few situations where bumping the shutter was necessary, and I'd simply do exactly as you said, composing the photo to one side of the frame and using what I had availalbe.

I especially like this one (minus his shadow), where I was able to capture the members who had video-conferenced in, to give a sense he was speaking to "someone"

http://farm1.static.flickr.com/254/525335703_473f688f87_b.jpg

June 01, 2007 4:20 PM  
Blogger Nacho said...

This is not the same technique and is applied to different kind of shots, but it's another way of hacking your camera sync speed and obtain shocking photos:

http://farm1.static.flickr.com/254/525335703_473f688f87_b.jpg

It looks that to set up this you should have some knowledge of electronics -which I don't- but all the same, looks very interesting.

June 01, 2007 5:21 PM  
Blogger Nacho said...

Sorry, I correct the link of my previous comment:

http://www.diyphotography.net/diy_high_speed_photography_at_home

June 01, 2007 5:23 PM  
Blogger David said...

Ha ha... Told you Neil has more class and style!

June 01, 2007 7:22 PM  
Anonymous Peter S said...

Cool trick, never thought of using the partial frame for effect...

That made me think putting a finger or two on the top part of your lens to get a fast ND grad filter. Or drop a stop on the flash by covering it with a finger.

Of course completely different but anyway...

June 01, 2007 7:35 PM  
Anonymous conrad erb said...

last time I remember doing this, I was able to get consistent 1/400th of a second on my canon 20D with a very very slim line of the frame not synching. not too shabby for those of us who shoot in strong light...

June 01, 2007 8:07 PM  
Anonymous Anonymous said...

any chance we lear about cheating a pocketwizard's sync speed

June 01, 2007 8:31 PM  
Blogger dwbell said...

Ben is a Hobby alright......

.....just check out the shorts!

;-)

Nice series David, top drawer as always.

Kind Regards
DWBell

June 02, 2007 12:52 AM  
Blogger Kevin Yong said...

Thanks Dave - that tip is Genius!

June 02, 2007 6:01 AM  
Blogger Craig said...

If I could just learn at 39 what your son has learned at 6 :)

June 02, 2007 5:33 PM  
Blogger Andy said...

I just tested this with my Pentax K10D and unfortunately it doesn't seem to work - the camera just doesn't send a signal to the hotshoe past the max sync speed of 1/180th

:(

June 03, 2007 7:00 AM  
Blogger A J FRENCH said...

This comment has been removed by the author.

June 03, 2007 2:16 PM  
Blogger A J FRENCH said...

just tried this out with my 20D and an SB-26 on a sync cord
and thought that it might be interesting for other 20D users
here are the results

posted here

seems the 20D's useable area is at the top of the frame

June 09, 2007 8:12 AM  
Anonymous Andrew Ferguson said...

@AJ

Thanks for posting your 20D results. I'll have to try this out and see if I can discover whether the top area being usable for your 20d is the same on my 350d.

Sometimes I feel like the lone Canon guy when dealing with lighting :P

June 20, 2007 5:26 PM  
Anonymous Will Hore-Lacy said...

I just did this test with a 30D, sb-22s and an ebay trigger and got a similear result to aj, it still synced at 1/320 but I had a little more dark area 1/400.

June 22, 2007 10:49 PM  
Anonymous Will Hore-Lacy said...

eBay sync update . . .
I just took the V2 eBay triggers for a test run today shooting indoor volleyball, available light was ok but I thought I'd try using some strobes for fill light (as seen previously on strobist). Anyway I found that they don't sync at 1/250 when the V1 triggers would go as high as 1/320. Anyway I'll try and do a side by side comparison and post it somewhere.

July 29, 2007 1:03 AM  
Blogger David said...

I just got a great tip on how to get high speed sync with a D200 (would work with most nikons) and pocket wizards (probably works well with skyports too, probably not with the ghetto-triggers though). You'll need an sb-800 or an sb-600 mounted on your camera, the remote flashes could be of any kind. Check this out:
http://www.flickr.com/photos/7902684@N02/810823064/

April 18, 2008 4:31 AM  

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