Results 1 to 19 of 19

Thread: how to expose for bright foreground and dark background?

  1. #1
    Member
    Join Date
    Jun 2004
    Location
    Singapore, Singapore, Singapor
    Posts
    205

    Unhappy how to expose for bright foreground and dark background?

    hi all, my colleague and i tried out night flash photography a few days ago and we have a question. hope you can help us.
    we went to the Arts House at about 7.30pm and the sky was a lovely dark blue hue. our model stood infront of the Arts House which was brightly lid. we used flash (he used 550ex on Canon 10D and i used SB28 on Nikon F100). the photographs exposed the model and building correctly but our blue sky was all black. is there a way to expose longer to get the blue sky yet not overexposing the building and the model?
    if we were on a long exposure mode of 2 to 3seconds, is there some trick (besides asking the model not to move) to keep the model sharp? we encounter some blurring on the model due to the longer exposures.

    any advice the above and night flash portrait photography will be appreciated.
    thanks!!!

  2. #2
    Member
    Join Date
    Jan 2004
    Location
    Central
    Posts
    295

    Default

    Quote Originally Posted by tubbykat
    hi all, my colleague and i tried out night flash photography a few days ago and we have a question. hope you can help us.
    we went to the Arts House at about 7.30pm and the sky was a lovely dark blue hue. our model stood infront of the Arts House which was brightly lid. we used flash (he used 550ex on Canon 10D and i used SB28 on Nikon F100). the photographs exposed the model and building correctly but our blue sky was all black. is there a way to expose longer to get the blue sky yet not overexposing the building and the model?
    if we were on a long exposure mode of 2 to 3seconds, is there some trick (besides asking the model not to move) to keep the model sharp? we encounter some blurring on the model due to the longer exposures.

    any advice the above and night flash portrait photography will be appreciated.
    thanks!!!
    Use a tripod. Try a gradated filter.

  3. #3
    vince123123
    Guests

    Default

    i would think that the solution would be to combine both flash and slow shutter sync (your 2-3 seconds thingy) - the flash "freezes" and exposes the foreground while the slow shutter gets the background. u'd also need a tripod.

  4. #4

    Default

    Quote Originally Posted by vince123123
    i would think that the solution would be to combine both flash and slow shutter sync (your 2-3 seconds thingy) - the flash "freezes" and exposes the foreground while the slow shutter gets the background. u'd also need a tripod.
    Yes, that's the way to do it but a couple of things to take note of is that you need to take light reading(spot) for the sky first. Also you have to ensure that the model doesn't move/fidget when taking the shot. 2-3s is a bit too extreme la. Try a higher ISO instead.

  5. #5
    Member
    Join Date
    Jun 2004
    Location
    Singapore, Singapore, Singapor
    Posts
    205

    Default

    Quote Originally Posted by vince123123
    i would think that the solution would be to combine both flash and slow shutter sync (your 2-3 seconds thingy) - the flash "freezes" and exposes the foreground while the slow shutter gets the background. u'd also need a tripod.
    i understand the slow shutter process but as it continues to expose for the background, wouldn't my bright foreground of the building be overexposed?
    should i take meter reading of sky or building? how confusing!

    another question, the speedlight, if using TTL, how does it know where the "target" is? is it based on what we focus on with the camera?

    very new to using the speedlight so therefore the questions, thanks

  6. #6

    Default

    i think thats for the solution for a backlit scenario...
    ...what you want to do here is to try tingchiyen's suggestion

  7. #7

    Default

    Quote Originally Posted by LiOnElLiN
    i think thats for the solution for a backlit scenario...
    ...what you want to do here is to try tingchiyen's suggestion
    Using a tripod for long exposure is right. But when you don't have a straight line seperating your brighter and darker area, how is a graduated ND filter going to help may I ask?

    The reason for using flash+slow sync is firstly to expose the background or sky adequately, then the flash will provide the needed illumination for the model.

  8. #8

    Default

    Quote Originally Posted by CaeSiuM
    Using a tripod for long exposure is right. But when you don't have a straight line seperating your brighter and darker area, how is a graduated ND filter going to help may I ask?

    The reason for using flash+slow sync is firstly to expose the background or sky adequately, then the flash will provide the needed illumination for the model.
    hard to say whether theres a straight line or not unless he shows a picture yah?

  9. #9

    Default

    Slow sync flash works like this:

    You set the camera to Av mode (NOT P mode) and set the flash on. Then you just take the picture.

    The flash will illuminate the subject in the foreground, but the shutter will remain open until the dark background is sufficiently exposed (you will usually get a nice azure blue). Because the duration of the flash itself is very short, the subject in the foreground will NOT be overexposed, in fact should be correctly exposed.

    Only problem is that this usually looks very "fake", as though the subject had been taken in a studio and cut out and pasted onto the background. My wife does not like the effect so I do not use it often.

  10. #10
    Senior Member Virgo's Avatar
    Join Date
    Dec 2003
    Location
    West of Singapore
    Posts
    4,816

    Default

    My suggestions:

    1. Mount your camera with flash on a tripod

    2. Set to AV mode, use a higher f-stop, f/6.3 and above to get better DOF

    3. Use a higher ISO to get faster shutter speed

    4. May need to set Exposure Compensation to a higher value, say +0.3 or +0.6

    4. Ask you subject not to move even after the flash fires

    5. Focus on your subject, ie, the model. Half pressed the shutter or cable-release button

    6. Compose and shoot!

    You should get a clear blue hue of the sky, but must be fast, cos it goes off pretty fast too!
    Kind Regards
    My Picture Website

  11. #11
    Member
    Join Date
    May 2003
    Location
    Singapore
    Posts
    984

    Default

    i dont understand a bit of the discussion here... we are talking about a bright foreground and a dark background. how does using a flash gun (im assuming that is camera mounted) help in the problem? lots of people have been suggesting that.

  12. #12
    Member
    Join Date
    May 2003
    Location
    Singapore
    Posts
    984

    Default

    Quote Originally Posted by tubbykat
    i understand the slow shutter process but as it continues to expose for the background, wouldn't my bright foreground of the building be overexposed?
    should i take meter reading of sky or building? how confusing!

    another question, the speedlight, if using TTL, how does it know where the "target" is? is it based on what we focus on with the camera?

    very new to using the speedlight so therefore the questions, thanks
    based on my limited knowledge, there is little to do on the camera to help the situation. film has got a wider exposure latitude. digital on the other hand will have a great difficulty in this situation but post production will help. (photoshop)

  13. #13
    Member
    Join Date
    Jan 2004
    Location
    Central
    Posts
    295

    Default

    Quote Originally Posted by CaeSiuM
    Using a tripod for long exposure is right. But when you don't have a straight line seperating your brighter and darker area, how is a graduated ND filter going to help may I ask?

    The reason for using flash+slow sync is firstly to expose the background or sky adequately, then the flash will provide the needed illumination for the model.
    Whoops, differing opinions... I think you might be right, though, you'd still need a flash to make sure you can see faces and details against the bright building background, while trying to catch the sky as well with a longer exposure. My thought was to use the grad. filter to darken the building-half of the exposure by a couple stops so that the sky can come through.
    How about mixing both methods? Slow synch with sky-exposure?

  14. #14

    Default

    Quote Originally Posted by showtime
    based on my limited knowledge, there is little to do on the camera to help the situation. film has got a wider exposure latitude. digital on the other hand will have a great difficulty in this situation but post production will help. (photoshop)
    The other solution is to use graduated ND filters for the bright foreground, flash to illuminate the model.

    Cheers!

  15. #15
    Member
    Join Date
    Jun 2004
    Location
    Singapore, Singapore, Singapor
    Posts
    205

    Default

    Quote Originally Posted by showtime
    i dont understand a bit of the discussion here... we are talking about a bright foreground and a dark background. how does using a flash gun (im assuming that is camera mounted) help in the problem? lots of people have been suggesting that.
    you are the only one who understood my problem! but thanks all of you, i think tingchiyen and UY79 are right, we will try their suggestions next shoot.


  16. #16
    Senior Member jOhO's Avatar
    Join Date
    Apr 2003
    Location
    Singapore
    Posts
    6,485

    Default

    use photoshop....

  17. #17

    Default

    very simple



    just set:

    tripod
    Av
    f5.6
    fill flash (minus how many stop is up 2u)


    and bracket for the shutter speed.


    whether u spot meter for the model's face or spot meter for a mid-tone in the background or anyhow matrix meter for anywhere in the scene or put ND filter or not, because u r in Av with f5.6, the difference in exposure still hinges on the shutter speed. thats why the main thing here is to bracket for shutter speed

  18. #18
    Deregistered
    Join Date
    Jan 2004
    Location
    Perth
    Posts
    509

    Default

    Quote Originally Posted by tubbykat
    hi all, my colleague and i tried out night flash photography a few days ago and we have a question. hope you can help us.
    we went to the Arts House at about 7.30pm and the sky was a lovely dark blue hue. our model stood infront of the Arts House which was brightly lid. we used flash (he used 550ex on Canon 10D and i used SB28 on Nikon F100). the photographs exposed the model and building correctly but our blue sky was all black. is there a way to expose longer to get the blue sky yet not overexposing the building and the model?
    if we were on a long exposure mode of 2 to 3seconds, is there some trick (besides asking the model not to move) to keep the model sharp? we encounter some blurring on the model due to the longer exposures.

    any advice the above and night flash portrait photography will be appreciated.
    thanks!!!
    tubbykat, you need to find out the dynamic range of the scene. Your camera sensor will have a dynamic range of 5 stops. If the dynamic range is greater than 5 stops, then you WILL blow out or black out part of your picture unless you do something to it.

    Bear with me, I am going to get a bit technical here. You either pull out a light meter or use the spot meter on your camera. Into your light meter you dial ISO 400, shutter speed 1 sec (I am just guesstimating exposures for you here). Point the meter at the model, and it says F/11. Point the meter at the building, and it says F/11. Point the meter at the sky, and it says F/1.4. In this case, it will be impossible to capture the entire scene as the dynamic range too great - there are 6 f-stops between the darkest and brightest part of the scene.

    There are ways to get around this situation:

    1. Use a fill flash. This is not an option for you, because you use a fill flash to add light to what is dark. There is no way to fill flash the sky, so forget it.

    2. Use a graduated filter. This may be an option if you can compose your image in such a way that there is a definite line between the bright and dark area.

    3. Recompose the image without the sky.

    However, with digital cameras, there is a fourth option!

    4. Mount your camera on a tripod. Expose as normal for the model and the building. Then expose for the sky. Combine the two pictures in photoshop. Link to article describing exposure blending. When I do this, I set the camera to "P" mode and shoot the model with the flash - this at least guarantees that the subject will be sharp. I then turn the flash off and switch to aperture priority and dial in exposure compensation to shoot the background.

    Hope this helps

  19. #19

    Default

    If your sky is very blue, but not the very bright type of blue...like navy blue, then it's impossible. Tried before with another building, with bracketing and tripod and stuff. Anyway, it doesn't have the impact if the sky is more than 3-4 stops difference from the building. If you really want it, you expose for the building and model (fill-in), that's what you see on some wedding shoots, the sky is like midnight blue. That time window is actually just like 15-20 mins.
    That is to say you do not use the equipment to suit the shoot, rather.... you time your shoot.

    Just aim to capture the model + building. Typical night shoot + model kinda settings can liao.
    Last edited by 2100; 25th June 2004 at 06:03 PM.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •