between 1st and 2nd curtain flash


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fongi

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Aug 19, 2008
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#1
hi to all, i need to clarify something which i have doubts... the diff between 1st and 2nd curtain flash.
if let's say i wanna capture the surrounding light using a long exposure, say 2 secs... and at the same time takin a shot of a person (without the person having any motion blur due to the long exposure), i shd use 1st curtain, at the same time, tripod is been used... am i correct? i cant use 2nd curtain cos the person will have movement recorded...

on the other hand, if i shoot with 2nd curtain, the person will have trailing movement and a image when the flash flashes b4 the shutter close... but the person's image is not clear, it seem rather opaque, like a ghost.... how do i capture the movement and at the same time record a clear image of the person in 2nd curtain?

btw, using canon 40D with 580ex mk II

hope i make myself clear...:embrass: cos quite diff to put in words;p

TIA for all the advise
 

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Dream Merchant

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Jan 11, 2007
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#2
It doesn't matter whether you're using 1st or 2nd shutter curtain if the person is moving, you have a long shutter opening and there's enough ambient light to register an image - you will get motion blur. The only difference it would make is the apparent direction of the movement.

For the person to appear CLEAR towards the end of the long shutter opening while using the 2nd shutter curtain option in your camera, you also have to check your flash settings.

Why not post up a shot that you took? It would be much easier for members here to actually see what could have gone wrong.
 

fongi

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Aug 19, 2008
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#3
tks. will post a pic tmo when i have the chance... i deleted the pic cos it wasn't to my liking. tks ;)
 

Dream Merchant

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#4
tks. will post a pic tmo when i have the chance... i deleted the pic cos it wasn't to my liking. tks ;)
No worries, but without a samplke of what went wrong, there's no way we can have an idea.

It's also good to keep bad photos during learning phases as a record and reference. ;)

Anyways, I suspect it has to do with ambient light and more specifically, flash settings. EF systems are kinda a PITA sometimes.
 

fongi

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Aug 19, 2008
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#5
got the pic liao... not sure if i did it right...


1st curtain, bounce flash, shutter speed 2 sec


2nd curtain, bounce flash, shutter speed 2 sec.

both were taken with tripod
not sure if i shd use direct flash or not... tks for help and advise... i'm trying to get a sharp or clear facial expression... but end up having ghost like image... or is this acceptable?
 

kietgnoel

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Dec 24, 2004
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#6
Your subject (the girl) was not moving in one direction but turning round and round. In this case, you will always get the ghost-like image as long as there is sufficient ambient light and your exposure is long enough.

I suggest you use a much shorter exposure time. As short as possible while still allowing enough ambient light to fill up the background. Say, try 1/10 as a start and adjust accordingly depending on the effect that you want.

As for whether to use 1st or 2nd curtain, imagine a photo showing a person running. The photo gives you the impression that the person is running. You would see some trailing images of the person which gives you the impression that he is running forwards. The trailing images would be "behind the person" and less distinct than the first image. This is acheived by using 2nd curtain.

Now image the person is running backwards. The trailing and less distinct images would be in front of the person which gives you the impression that he is running backwards. This is achieved by using 1st curtain.

In your photo, the girl is turning too fast for the exposure time that you used. Also, she was not turning at a constant enough rate. It looks she stood facing one direction for a moment and then quickly turn to face another direction. She probably did this 2 or 3 times during your exposure time. The result is that you see a few disctinct enough images of her - the ghost-like images.
 

Octarine

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Jan 3, 2008
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#7
You are using f/13, ISO100 and 2sec shutter - why? Your intention is to capture the person clearly (no motion blur) including the background. So you need a fast shutter to freeze the motion. In addition, increase the ISO speed and open aperture to capture enough light from the background. In such conditions the normal metering in Tv and Av mode of Canon doesn't help much. The metering in Av and Tv will always meter for the dark background, resulting in long exposure times. Use P (gives proper foreground exposure but dark background) or use M to balance both manually. In addition you can use FEC to balance ambient light and flash.
More to read here, see under "Fill Flash": http://www.photonotes.org/articles/eos-flash/

To capture trails use a lower shutter speed (e.g. 1/20s) and use spot metering for the person. The background doesn't really matter in such cases. 2nd curtain shutter will freeze the person at the end of the trail. Length of trail depends on motion speed and shutter speed.
 

fongi

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Aug 19, 2008
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#9
You are using f/13, ISO100 and 2sec shutter - why? Your intention is to capture the person clearly (no motion blur) including the background. So you need a fast shutter to freeze the motion. In addition, increase the ISO speed and open aperture to capture enough light from the background. In such conditions the normal metering in Tv and Av mode of Canon doesn't help much. The metering in Av and Tv will always meter for the dark background, resulting in long exposure times. Use P (gives proper foreground exposure but dark background) or use M to balance both manually. In addition you can use FEC to balance ambient light and flash.
More to read here, see under "Fill Flash": http://www.photonotes.org/articles/eos-flash/

To capture trails use a lower shutter speed (e.g. 1/20s) and use spot metering for the person. The background doesn't really matter in such cases. 2nd curtain shutter will freeze the person at the end of the trail. Length of trail depends on motion speed and shutter speed.
actually as mention, i was doin a test shot, i wanna know y i cant record a clear enof image (eg. the face) when i use 2nd curtain, for 2nd curtain, to my understanding, the flash flashes just b4 the shutter close, thus recording a trailin image (in this case, the spinning girl), wat i dun understand is how come after the flash flashes, there wasn't any clear face been recorded (i hope i dun sound very blur :embrass:)... like for eg. the image which i got from the another site
http://www.thedigitalstory.com/blog//second_curtain_flash.jpg
this image manage to record a trailing motion, with the card render rather clearly as a result of 2nd curtain... like wise for 1st curtain (the opp effect)... but somehow i couldn't get the kind of result which i have in mind (like the image of the fallin card i attach)... i was wondering if i shd pay more attention to certain areas which i have overlook... so hope to get some tips on how u guys manage this situation...:embrass:
 

fongi

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Aug 19, 2008
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#10
correct me if I am wrong... I believe what you want is to freeze the little in different position in the same img. :dunno:

no lah, i'm not tryin to freeze her in different position... dat'll be like doing stroboscopic shots... i wanted trailin motion follow by the image... just wondering if i did is correct of not... or do i have to tell my subject to turn slowly? or did i miss out doin something which i shd have done? pls enlighten me ;)
 

fongi

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Aug 19, 2008
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#14
2 sec is way toooooooooo longgggggggg.

and your flash is veryyyyyyyyy weak.
so i gotta use full power and shorten the the shutterspeed? but i wanna capture some movement leh. does it oso gotta do with the subject? as in, instead of turning in circle, may be get her to move from left to right?
 

catchlights

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Sep 27, 2004
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#16
so i gotta use full power and shorten the the shutterspeed? but i wanna capture some movement leh. does it oso gotta do with the subject? as in, instead of turning in circle, may be get her to move from left to right?
basic photography 101, your flash suppose to record the correct exposure of the subject, and the shutter and aperture setting suppose to record underexposed by one to two stops.

to make your life easier, just ask her stand still first, and rise both hand when you fire the shutter. and later you can try ask her to swing upper body left and right do more test.
 

fongi

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Aug 19, 2008
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#17
basic photography 101, your flash suppose to record the correct exposure of the subject, and the shutter and aperture setting suppose to record underexposed by one to two stops.

to make your life easier, just ask her stand still first, and rise both hand when you fire the shutter. and later you can try ask her to swing upper body left and right do more test.
u mean to say, to get the most idea result would be mergin the images? :think:
is there no way i could get it right on camera? btw have u guys tried b4 and get a satisfactory result on cam? can show some pic?:)
 

J-Chan

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Sep 21, 2005
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#19
I think the problem with the pic you posted lies with the flash exposure.. simply put, bouncing the flash and at f/13 the light falling on your subject isn't enough for a proper flash exposure, thus with almost only ambient your subject its bound to get blur with any movement.. try with a larger aperture and direct flash..
 

fongi

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Aug 19, 2008
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#20
I think the problem with the pic you posted lies with the flash exposure.. simply put, bouncing the flash and at f/13 the light falling on your subject isn't enough for a proper flash exposure, thus with almost only ambient your subject its bound to get blur with any movement.. try with a larger aperture and direct flash..

i've tried the method u just mention, i couldn't get the trail of movement...
an eg. of wat i have in mind is something like this...
http://yanikphotoschool.com/wp-content/uploads/2009/03/yan_04683.jpg
 

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