Second Curtain Sync

Jethro790 · 29th of October 2007 (Mon)

Can someone explain or demonstrate what this means for me? The manual says something about a light trail following the subject... Excuse my ignorance.

Thanks!

E-K · 29th of October 2007 (Mon)

Basically the flash will fire just before the shutter closes rather than when it just finishes opening. So say you were photographing a car with a relatively slow shutter speed. You will see the red lights registering on the image behind the car and then the flash illuminates the car and freezes it -- so you have a nice bright image of the car with a light trail behind it.

With first curtain sync the light trail would be in front of the car. You could always drive in reverse I suppose

.

e-k

mikep00 · 29th of October 2007 (Mon)

A simple example is a moving car in low light. If you shoot it regular (first curtain shutter), you will have the flash go off at the beginning on the shot. So the photo would be a sharp image of a car, with a motion blur going forward. Kinda seems backwards, but if you set it for 2nd curtain, then you will have a motion blur with the sharp image at the front.
That would convey the movement of the car much better. Test out the 2 settings on a moving object and you will understand

Tommy · 29th of October 2007 (Mon)

Now if you want to get technical....

You camera has 2 shutter curtains. When you click the shutter release, the first curtain opens exposing the film (in our case, sensor). Once the media has been exposed for the set amount of time, the second curtain closes behind it. At our camera's sync speed (the 30D is 1/250th) the second curtain closes the instant the first one if fully opened. Anything faster than sync speed and the second curtain starts to close before the first one is even open all the way. Your flash is normally set to fire as soon as the first curtain is open, before the second one starts to close. If you set it to 2nd curtain sync, it fires as soon as the 2nd curtain is about to close. So at 1/250th shutter speed, you'll see no effect of 2nd curtain sync. As far as the effect on slower shutter speeds, the others here have already described that to you.

Sorry if you didn't want the technical stuff.... I felt like typing though... lol...

Curtis N · 29th of October 2007 (Mon)

Illustrated here:
http://web.canon.jp/imaging/flashwor...ain/index.html

grphx · 30th of October 2007 (Tue)

Good thread!

tmartin110 · 30th of October 2007 (Tue)

I found these videos on You Tube were very helpful in breaking it down to simple science. Snapfactory is the video creator and they have several that are helpful.

http://www.youtube.com/watch?v=Xnn5nzPvoIM

bwolford · 30th of October 2007 (Tue)

The same thing can happen with rain drops. With first curtain sync the rain appears to fall up, with second curtain sync, rain falls down...

Big WIll · 30th of October 2007 (Tue)

Go out and try it for yourself and it will make a lot more sense

Jethro790 · 30th of October 2007 (Tue)

Quote:

Originally Posted by Big WIll

Go out and try it for yourself and it will make a lot more sense

Thats a good idea!

Thanks everyone, I think I get it.

dancinec · 30th of October 2007 (Tue)

Here is what I have read in nature photography magazine recommending the second curtain sync. The animal may react to the flash, but since the flash comes as the second curtain is closing, the animal's reaction comes after the exposure.

29th of October 2007 (Mon)	#1
Jethro790 Goldmember Join Date: Nov 2004 Location: Southern New Hampshire Posts: 2,189 IMAGE EDITING OK	Second Curtain Sync Can someone explain or demonstrate what this means for me? The manual says something about a light trail following the subject... Excuse my ignorance. Thanks! __________________ If you must know...

29th of October 2007 (Mon)	#2
E-K Member Join Date: Sep 2006 Location: Canada Posts: 945 IMAGE EDITING OK	Re: Second Curtain Sync Basically the flash will fire just before the shutter closes rather than when it just finishes opening. So say you were photographing a car with a relatively slow shutter speed. You will see the red lights registering on the image behind the car and then the flash illuminates the car and freezes it -- so you have a nice bright image of the car with a light trail behind it. With first curtain sync the light trail would be in front of the car. You could always drive in reverse I suppose . e-k

29th of October 2007 (Mon)	#3
mikep00 Member Join Date: Jun 2007 Posts: 81	Re: Second Curtain Sync A simple example is a moving car in low light. If you shoot it regular (first curtain shutter), you will have the flash go off at the beginning on the shot. So the photo would be a sharp image of a car, with a motion blur going forward. Kinda seems backwards, but if you set it for 2nd curtain, then you will have a motion blur with the sharp image at the front. That would convey the movement of the car much better. Test out the 2 settings on a moving object and you will understand

29th of October 2007 (Mon)	#4
Tommy I have a Peepster. Join Date: Aug 2005 Location: Cleona, PA Posts: 2,259	Re: Second Curtain Sync Now if you want to get technical.... You camera has 2 shutter curtains. When you click the shutter release, the first curtain opens exposing the film (in our case, sensor). Once the media has been exposed for the set amount of time, the second curtain closes behind it. At our camera's sync speed (the 30D is 1/250th) the second curtain closes the instant the first one if fully opened. Anything faster than sync speed and the second curtain starts to close before the first one is even open all the way. Your flash is normally set to fire as soon as the first curtain is open, before the second one starts to close. If you set it to 2nd curtain sync, it fires as soon as the 2nd curtain is about to close. So at 1/250th shutter speed, you'll see no effect of 2nd curtain sync. As far as the effect on slower shutter speeds, the others here have already described that to you. Sorry if you didn't want the technical stuff.... I felt like typing though... lol... __________________ Tommy ___________________________ "Vision without execution is hallucination" - Thomas Edison (1847-1931) MySpace \| Facebook \| ModelMayhem \| Blog \| Central PA Wedding and Senior Photographer \| Gear List

29th of October 2007 (Mon)	#5
Curtis N Master Flasher Join Date: Apr 2005 Location: Northern Illinois, US Posts: 18,993	Re: Second Curtain Sync Illustrated here: http://web.canon.jp/imaging/flashwor...ain/index.html __________________ "If you're not having fun, your pictures will reflect that." - Joe McNally Chicago area POTN events Flash Photography 101 \| The EOS Flash Bible \| Techniques for Better On-Camera Flash \| How to Use Flash Outdoors \| Excel-based DOF Calculator

30th of October 2007 (Tue)	#6
grphx Member Join Date: Oct 2006 Location: Oklahoma Posts: 711	Re: Second Curtain Sync Good thread! __________________ Canon 50D, Canon 430ex(x2) Canon 70-200mm F/2.8 L Tamron 17-50mm f/2.8

30th of October 2007 (Tue)	#7
tmartin110 Member Join Date: Aug 2007 Location: Fredericksburg, VA Posts: 44	Re: Second Curtain Sync I found these videos on You Tube were very helpful in breaking it down to simple science. Snapfactory is the video creator and they have several that are helpful. http://www.youtube.com/watch?v=Xnn5nzPvoIM

30th of October 2007 (Tue)	#8
bwolford Goldmember Join Date: Aug 2006 Location: Tampa, Florida Posts: 3,704 IMAGE EDITING OK	Re: Second Curtain Sync The same thing can happen with rain drops. With first curtain sync the rain appears to fall up, with second curtain sync, rain falls down... __________________ Brice Gear List Sample Gallery

30th of October 2007 (Tue)	#9
Big WIll "Slight breach of etiquette" Join Date: Oct 2005 Location: Chester & Bucks UK Posts: 2,363 IMAGE EDITING OK	Re: Second Curtain Sync Go out and try it for yourself and it will make a lot more sense __________________ Computers blur the boundaries... We are being released from the suddenness of photography, the suddenness of the shutter

30th of October 2007 (Tue)	#11
dancinec Cream of the Crop Join Date: Apr 2005 Location: Carlsbad, California Posts: 8,035 IMAGE EDITING OK	Re: Second Curtain Sync Here is what I have read in nature photography magazine recommending the second curtain sync. The animal may react to the flash, but since the flash comes as the second curtain is closing, the animal's reaction comes after the exposure. __________________ Dennis Canon 20D, 30D, 40D, 50D, Canon 100 mm Macro, Canon 100-400mm, Canon 400mm 5.6L, Canon TC 1.4X, Tamron 28-75 mm, Bogen 3221 Tripod, Kirk BH-1 ballhead, Sigma EF-500 DG Super Flash, Canon 580 II Flash, Better Beamers, Whimberly Plamp. My galleries

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