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Thread: Second Curtain

  1. #1
    Senior Member iND's Avatar
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    Second Curtain

    I dont usually reset my flash to second curtain but I think I understand the advantages.
    Ie. any movement will be recored before the flash and thus appearing behind and not in front of a moving object in a flash.
    So why is this not the default?
    When would I choose first curtain if it was not the default present?

    Thank.
    I learn so much from you guys.

  2. #2
    Senior Member neuroanatomist's Avatar
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    Blinks. Basically, the time between the pre-flash for eTTL and a first-curtain flash isn't significant, but with second-curtain flash, the delay from pre-flash is enough that the reflexive blink of a subject will be illuminated by the flash, rather than being part of the ambient. Put another way, if you shoot people looking at the camera with second-curtain sync, you'll get a much higher percentage of shots with people caught with their eyes closed in mid-blink.

    There might be other reasons, too, but that's the one that comes to mind...
    Last edited by neuroanatomist; 01-02-2012 at 03:40 AM.

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    Senior Member Rocco's Avatar
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    Quote Originally Posted by neuroanatomist View Post
    Blinks. Basically, the time between the pre-flash for eTTL and a first-curtain flash isn't significant, but with second-curtain flash, the delay from pre-flash is enough that the reflexive blink of a subject will be illuminated by the flash, rather than being part of the ambient. Put another way, if you shoot people looking at the camera with second-curtain sync, you'll get a much higher percentage of shots with people caught with their eyes closed in mid-blink.

    There might be other reasons, too, but that's the one that comes to mind...
    Nailed it on the head. The issue is eTTL and blinking. With static subjects there is no advantage between the two. Also, at faster shutter speeds, there isn't much advantage to the rear curtain sync.

    I have also read that with Nikon shooting in AV (or whatever Nikonian is for that) you will actually get a slower shutter speed than you would get in the exact same shooting conditions with first curtain sync. I'm not in a position to test that on my 7D, but Nikon presumably does that because the blur effect is what they're assuming you have in mind using rear curtain.
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    Don't forget that using the 2nd curtain setting can also allow more ambient (or natural) light into the exposure if you want it. Natural light being a softer light than speedlites.
    Brett

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    Senior Member neuroanatomist's Avatar
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    Quote Originally Posted by Firephoto View Post
    Don't forget that using the 2nd curtain setting can also allow more ambient (or natural) light into the exposure if you want it. Natural light being a softer light than speedlites.
    I'm not sure I understand that one? I would think that the exposure (based on metering and the pre-flash) would be identical regardless of the timing of the flash relative to the shutter curtains. Obviously, you can adjust the ratio of flash to ambient in a number of ways (manual camera/flash, EC or FEC, max shutter in Av mode setting, etc.). But I don't think that just first vs. second curtain should make a difference.

    Can you explain? Thanks!

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    Senior Member conropl's Avatar
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    Quote Originally Posted by neuroanatomist View Post
    I'm not sure I understand that one? I would think that the exposure (based on metering and the pre-flash) would be identical regardless of the timing of the flash relative to the shutter curtains. Obviously, you can adjust the ratio of flash to ambient in a number of ways (manual camera/flash, EC or FEC, max shutter in Av mode setting, etc.). But I don't think that just first vs. second curtain should make a difference.

    Can you explain? Thanks!
    In one of Scott Kelby's books he says that using 2nd curtain will help keep the background from going dark. He even has a rather dramatic set of pictures - the first was 1st curtain and it had a very dark background; and the second used 2nd curtain (and he said that was the only change) and the background came out well lit.

    I do not get it myself... so I tried to duplicate his results with a subject with a dark background, but every shot looked the same (looking on the LCD display) whether I used 1st or 2nd curtain.

    I guess I still do not get it. Same exposure, just different sequencing of the light should not make a difference in the outcome.
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    When I use second shutter

    I find that second curtain is good for low ambient light portaits with long exposures. People tend to shift and move after a flash goes off. If the shutter is still open they create a large amount of blur around themselves. The comments about getting more ambient light with second curtain seem to be part of the story. The part that I think is missing is that when using longer exposure times it is usually better for portraits of close subjects to expose for the amount of background exposure you want and then at the last instant, fire the flash to capture the closer subject. It just seems that people being photographed hold still until the flash fires. With the flash on second curtain, people tend to stay still during the ambient exposure, and then move after the exposure.

    Have done some portait work in extreme low light. I've consistently found this approach to be very effective. I also tend to use manual flash control under these conditions to avoid a preflash as people sometimes will start to move thinking that the photo is done already.

    Hope this helps,
    Jeff

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    Quote Originally Posted by conropl View Post
    In one of Scott Kelby's books...
    Scott Kelby is a great photographer, and his book has lots of good information, but here he is clearly very wrong. The reason for his mistake is this. In certain cameras (older Nikons), set to certain modes (autoexposure and autoflash), 1st curtain would rely more on the flash and less on the shutter to make the exposure. Whereas 2nd curtain caused the autoexposure to rely less on the flash and more on the shutter -- which means longer exposure durations. All he really should have has said is that "2nd curtain is *also* good for overriding certain AE quirks in certain cameras", but I don't think he realized that it was only a quirk with his particular camera brand and model.

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