1st & 2nd curtain

Discussion in 'Beyond the Basics' started by jocose, Oct 20, 2005.

  1. jocose

    jocose TPF Noob!

    Joined:
    Sep 16, 2005
    Messages:
    3,059
    Likes Received:
    118
    Location:
    dans la pissoir
    Can others edit my Photos:
    Photos NOT OK to edit
    I have a question about the above title. After playing with my camera a bit, I have discovered that one overexposes the scene more than the other.

    Can someone explain:
    1) what exactly is going on with the two
    2) when to use each
    3) historically, where the terms come from (sorry--I'm a bit of a history geek).

    Thanks.
     
  2. Rob

    Rob TPF Noob!

    Joined:
    Jan 29, 2005
    Messages:
    6,217
    Likes Received:
    134
    Location:
    London
    The below article explains a lot in detail, but here's quick guess for you:

    First curtain is the shutter opening, second is it closing, giving you a window of time (usually about 1/125th) to fire the flash. It also gives you a literal window onto the film plane, hence curtain. Sometimes you want to take a picture in dark conditions and expose a fixed background naturally and a moving subject with the flash e.g. a portrait of someone in the dark.

    http://photonotes.org/articles/eos-flash/index2.html
     
  3. jocose

    jocose TPF Noob!

    Joined:
    Sep 16, 2005
    Messages:
    3,059
    Likes Received:
    118
    Location:
    dans la pissoir
    Can others edit my Photos:
    Photos NOT OK to edit
    aaahhhh information overload :)

    I'm reading the link you sent...good stuff, but lots and lots and lots and lots of it !!
     
  4. hobbes28

    hobbes28 Incredible Supporting Member

    Joined:
    Jul 10, 2004
    Messages:
    4,807
    Likes Received:
    41
    Location:
    at work...
    Summary is that 1st and 2nd shutter are flash synchs. It just means that you would rather the flash fire with the opening of the shutter or the closing. Usually, it fires in the middle so the first should operate as normal where the second should make the shutter stay open a bit longer and could potentially over expose your shot.
     
  5. jocose

    jocose TPF Noob!

    Joined:
    Sep 16, 2005
    Messages:
    3,059
    Likes Received:
    118
    Location:
    dans la pissoir
    Can others edit my Photos:
    Photos NOT OK to edit
    so what are some practical examples of when you would use which?

    (BTW, for the record, the manual that came with my camera sucks!!)
     
  6. hobbes28

    hobbes28 Incredible Supporting Member

    Joined:
    Jul 10, 2004
    Messages:
    4,807
    Likes Received:
    41
    Location:
    at work...
    Most manuals do... :D

    Best reason to use syncs is for light streaks. You can take a picture of cars going down the road and have either the tail lights streak and the flash fire to show the car at the end or you can have it fire and show the car and have the lights trail through. I'll see if I can find some examples so I don't sound like your manual. :D
     
  7. ksmattfish

    ksmattfish Now 100% DC - not as cool as I once was, but still

    Joined:
    Aug 25, 2003
    Messages:
    7,021
    Likes Received:
    34
    Location:
    Lawrence, KS
    Can others edit my Photos:
    Photos NOT OK to edit
    Most cameras are 1st curtain. Some cameras/flashes have a 2nd curtain option. 1st curtain fires the flash just after the shutter opens. 2nd curtain fires the flash just before the shutter closes.

    For very short exposures it usually doesn't matter which you use. With longer exposures it can alter how movement is captured. Imagine you are shooting at night, and you have a car coming at you. With a longer exposure and 1st curtain the car would be frozen by the flash, but the headlights would continue towards the photographer because of the longer exposure. It would look like beams shooting out of the headlights. With 2nd curtain the headlights would go towards the photographer, and then the car would be frozen by the flash. The light trails would be dragging behind the car, which is how people tend to think motion looks.

    I don't know why your camera doesn't expose them the same. Somehow it must be metering them differently. Put the camera and the flash on the same manual exposure, and they should come out the same.
     
  8. jocose

    jocose TPF Noob!

    Joined:
    Sep 16, 2005
    Messages:
    3,059
    Likes Received:
    118
    Location:
    dans la pissoir
    Can others edit my Photos:
    Photos NOT OK to edit

    Thanks, Manual Hobbes.

    OK, that didn't sound as dirty in my head as it does when I read it on the screet :lmao:
     
  9. hobbes28

    hobbes28 Incredible Supporting Member

    Joined:
    Jul 10, 2004
    Messages:
    4,807
    Likes Received:
    41
    Location:
    at work...
    Um..er...*runs away...* :lmao:

    This is an example of rear sync by Nikon.

    [​IMG]
     
  10. jocose

    jocose TPF Noob!

    Joined:
    Sep 16, 2005
    Messages:
    3,059
    Likes Received:
    118
    Location:
    dans la pissoir
    Can others edit my Photos:
    Photos NOT OK to edit
    So you both use cars as your example, and it makes sense (Matt, I'm not sure I'm actually right about the different exposures...but to me one looked lighter than the other), but what else would you use it for? I mean, the idea couldn't have been created just to shoot car head and tail lights, could it?

    I so need to buy me a tripod!

    How do you get those kinds of shots...do you still use a lower shutterspeed, or does the 2nd curtain help make the effect?
     
  11. ksmattfish

    ksmattfish Now 100% DC - not as cool as I once was, but still

    Joined:
    Aug 25, 2003
    Messages:
    7,021
    Likes Received:
    34
    Location:
    Lawrence, KS
    Can others edit my Photos:
    Photos NOT OK to edit
    If the shutter is staying open longer than it's set to, then the camera is malfunctioning. 1/15th of a second is 1/15th of a second whether you are using no flash, 1st curtain, or 2nd curtain flash.

    Flash bulbs sort of fire in the middle of the exposure, and in some circumstances leaf shutter cameras/lenses the flash fire more in the middle, but with focal plane shutters (in almost all 35mm SLRs and DSLRs) it's definately either at the beginning or end of the exposure. Unless you are using something like the high speed sync feature like Canon flashes have, and then the flash is operating more like a flash bulb. In my example above, firing in the middle of the exposure would result in light trails extending both before the headlights, and trailing behind.
     
  12. hobbes28

    hobbes28 Incredible Supporting Member

    Joined:
    Jul 10, 2004
    Messages:
    4,807
    Likes Received:
    41
    Location:
    at work...
    Some of the advanced p&s's out there adjust shutter speed when you tell it to rear curtain sync and I think that Jocose is using the Canon S1 IS which, as far as I can remember, does the same thing. If it were an SLR, I would agree 150% with the camera being messed up. I used to have a Kodak DX6490 and it slowed my shutter down with rear curtain and I thought it was broken until I contacted them and they told me otherwise.
     

Share This Page

Search tags for this page

how to fire flash on 1st and 2nd curtain