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Old Mar 10, 2012, 3:15 AM   #1
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Default best flash for 7D that will allow 1/500 or faster

I shoot hummingbirds and need a flash that will let me shoot 1/500 or faster. Any suggestions? I have a 7D
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Old Mar 10, 2012, 4:12 AM   #2
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You need a flash that supports High-Speed Sync. The Canon Speedlites and
some third party flashes have this feature.

This video gives an exceptionally clear explanation of flash sync issues:
http://www.youtube.com/watch?v=hvZ6VujbhjM
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Old Mar 10, 2012, 10:21 AM   #3
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problem is it is not the flash but the body that sets the max sync speed.
In Canons case that is usually 1/250, Not positive but I think Nikon is 1/500 for sync.

High-Speed sync is an option but that greatly reduces the power output of the flash unit, as it takes multiple pops of the flash during a single shutter activation as the shutter curtain travels across the sensor.

And now for some good news,
when using flash as the main/sole light source, it is the flash duration, not your shutter speed that counts. depending on flash used this can even be in the 1/10000 range.

Here are some durations for the 580ex flash
1/1 power = 1/1000 second
1/2 power = 1/2000
1/4 power = 1/4000
1/8 power = 1/9000
1/16 power = 1/15000
1/32 power = 1/21000
1/64 power = 1/30000
1/128 power = 1/35000

that is from this link
http://www.photosbykev.com/wordpress...lash-duration/
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Last edited by PeterP; Mar 10, 2012 at 10:26 AM.
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Old Mar 10, 2012, 10:39 AM   #4
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Try letting the flash versus the shutter speed freeze the action.

Basically, use manual exposure with settings that would result in the photo being a few stops underexposed without a flash (making sure to stay within the sync speed limits of your camera, which should be 1/250 second with your 7D).

IOW, I'd set the shutter speed at 1/250, and dial in an aperture that shows you're about 3 stops underexposed. Your flash range will be reduced that way (stopping down the aperture). But, using that technique, the flash will freeze the action.

Basically, the camera is going to use a flash burst length that results in your subject being properly exposed that way, even though exposure with ambient light only would be underexposed.

Because the flash burst is very short (usually 1/1000 with a full power flash, with the burst length speeding up to 1/10000 second or even faster with lower flash power, with the burst length varying with subject range, aperture and ISO speed), the flash itself freezes the action (because your subject would be too dark to see any blur from movement without the flash if your settings result in significant underexposure from ambient light, and the flash burst length is very short).

You could use a Better Beamer to help with flash range and so that the flash burst will be shorter (as 1/1000 second is not going to freeze the movement with a hummingbird, and around 1/1000 is probably the duration of a full power flash, so you'll want to keep the flash burst length shorter to help out).
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Old Mar 10, 2012, 11:18 AM   #5
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Than you all. I shall get a Canon
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Old Mar 11, 2012, 2:06 PM   #6
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i just picked up some tt5 pocketwizards.. and they have an option of hyperscync up to 400.. if you go on youtube they show how it works.. was pretty neat on what the difference was
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Old Mar 11, 2012, 2:12 PM   #7
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I have ordered a Canon 580 which will go to very fast speeds. Thank you all
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Old Mar 12, 2012, 9:27 AM   #8
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Hi Lonefeather93,
the PW's are interesting, but at only 1/400 won't even put dent in stopping the speed of hummingbird wings. You need to get the duration over 1/1000, probably closer to 1/10,000

Also if you are using Canon did PW ever get the tt5's radio interference from the 580 flashes issues solved?
I remember hearing they were having all kinds of troubles with it.
I use the non automatic PLUS versions in our studio

Quote:
Originally Posted by lonefeather93 View Post
i just picked up some tt5 pocketwizards.. and they have an option of hyperscync up to 400..s
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Last edited by PeterP; Mar 12, 2012 at 9:37 AM.
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