Close
Close
Page 2 of 3 First 123 Last
  1. #11
    redkate is offline I'm new here!
    Join Date
    Sep 2011
    Location
    Vancouver, Canada
    Posts
    1

    Default

    Richard, thank you for this very clear, informative series on light. As a new photographer, I often find it difficult to deal with light conditions, so this is really useful information. Thanks also for including the exif information with each shot - it helps when I'm trying to set up a shot.

  2. #12
    RichardTaylor is online now dPS +1000 Club
    Join Date
    Nov 2009
    Location
    Sydney, Australia
    Posts
    7,912

    Default

    Thank you, and glad to be of help..

  3. #13
    btwien clicks is offline I'm new here!
    Join Date
    Sep 2011
    Location
    Mali
    Posts
    3

    Default

    Thanks for posting this. I have a question ... how do you choose the 'right Exposure Bias'?
    And when?
    --
    BP 19
    Koutiala, Mali, West-Afrika
    W: http://www.avonturiers.nl
    P: http://www.flickr.com/photos/btwienclicks

  4. #14
    Doug Sundseth's Avatar
    Doug Sundseth is offline Not quite older than dirt
    Join Date
    May 2010
    Location
    Thornton, Colorado, USA
    Posts
    1,855

    Default

    Experience: "In this light condition I've always needed +1-2/3 stops of exposure bias, so I'll start there."

    Chimping: "Looks blown out on the back of my camera; I'd better dial in some minus EC and reshoot."

    Histogram: "All stacked up on the left side, I'd better brighten it up a bit."

    Or in post, but that can fail pretty badly.

  5. #15
    RichardTaylor is online now dPS +1000 Club
    Join Date
    Nov 2009
    Location
    Sydney, Australia
    Posts
    7,912

    Default

    @ btwien clicks

    In addition to doug's comments.

    "When"
    Probably easier to say "when not"
    (1) Shooting manual
    You will still need to take the nature of the scene into account.
    (2) camera dependant, in a scene mode where you have very little control over the camera settings.
    (3) When you are looking at an "average scene" ie; not a lot of contrast and not a lot of real bright subjects (snow etc) or real dark subjects (a black car for example).

    #9 An average subject. This is a B&W conversion of a basically colourless subject shot in overcast lighting conditions so no harsh shadows. No exposure compensation.
    Even though it was shot in auto the exposure is ok.

    Tree trunk (B&W)

    Camera Canon PowerShot G11
    Exposure 0.017 sec (1/60)
    Aperture f/4.0
    Focal Length 6.1 mm
    ISO Speed 200
    Exposure Bias 0 EV
    Flash Off, Did not fire

    ------------------------

    "how do you choose the 'right Exposure Bias'?"

    If you are shooting with a the aid of a live histogram you can just dial it in as needed whilst watching the histogram.

    If you don't have a live a live histogram you need to ask a couple of things.
    (1) Do I want negative or positive exposure compensation?
    (2) Are there any highlights that may blow out?

    If you are shooting a predominately dark subject the camera will think the picture is too dark and will try to lighten it by increasing the exposure - so a black car may come out grey or dark grey.
    So you will need to reduce the exposure to compensate. How much depends on the subject. This was probably one of the more extreme cases (along with the train picture above). Normally for the subjects I shoot it is around -2/3

    #10 Here the subject was mostly darkish green and black engine. Light was diffused as it was morning fog.

    Working on the railway (2)

    Camera Canon EOS 5D
    Exposure 0.003 sec (1/320)
    Aperture f/10.0
    Focal Length 75 mm
    ISO Speed 800
    Exposure Bias -5/3 EV
    Flash Off, Did not fire
    Exposure Program Shutter speed priority AE

    Conversely if the subject is mostly very light, like snow or a beach in daylight, the camera will think the scene is over exposed and it will reduce the exposure making the scene look dark.
    You will need to dial in positive exposure compensation. How much depends on the scene. I havn't shot in snow but I would be looking at possibly two stops.

    #11 The light wall in the background made the camera think the scene was brighter than it was.

    Pink rose.

    Camera Canon EOS 40D
    Exposure 0.003 sec (1/320)
    Aperture f/5.6
    Focal Length 400 mm
    ISO Speed 200
    Exposure Bias +2/3 EV
    Flash Off, Did not fire

    #12 Sometimes with high contrast scenes you may need to make a decision on what detail you want to preserve. Stopping the whites blowing out was the main concern here as it didn't really matter if the background was a little dark
    Notice the exposure compensation..

    Reflected light - 5 minutes from home.

    Camera Canon EOS 40D
    Exposure 0.001 sec (1/1600)
    Aperture f/8.0
    Focal Length 400 mm
    ISO Speed 250
    Exposure Bias -4/3 EV

    Keep in mind there are other techniques you can use when shooting.
    (1) In difficult lighting conditions you may be able top bracket your exposures.
    (2) Using a different metering metering method (ie spot, instead of evaluative/are/matrix) may reduce the need to dial in any exposure compensation at all.

  6. #16
    ZafarSami's Avatar
    ZafarSami is offline dPS +1000 Club
    Join Date
    Nov 2012
    Posts
    6,723

    Default

    Thanks, this seems to be a very good resource for how to see light and how the camera sees it.

    I just had a thought; if the shutter speed is kept constant, wouldn't ISO 800 with -2 EV behave the same as ISO 200 with no compensation? Or if my math is wrong, a more general statement; would negative exposure compensation be also achieved by reducing ISO (light sensitivity)?

    My feeling is that if you shoot in manual mode then negative exposure compensation would behave like reducing ISO, but in aperture or shutter priority the camera would insist on calculating the exposure "correctly" based on all settings like SS, ISO, Aperture?

    Obviously you know what you are doing, therefore what am I missing here?
    Zafar
    Nikon D300s, Nikkor 50mm F1.4G, Tamron SP 24-70mm F2.8 VC, Tokina 11-16mm F/2.8, Tamron SP 70-200mm F2.8 VC, Nikkor 18-300mm F3.5-5.6, Nikon SB 900
    Flickr http://www.flickr.com/photos/zafarsami/

  7. #17
    sk66's Avatar
    sk66 is online now Lovable Contrarian
    Join Date
    Apr 2008
    Location
    Harrisburg, PA
    Posts
    15,270

    Default

    Quote Originally Posted by ZafarSami View Post
    My feeling is that if you shoot in manual mode then negative exposure compensation would behave like reducing ISO, but in aperture or shutter priority the camera would insist on calculating the exposure "correctly" based on all settings like SS, ISO, Aperture?
    This is "backwards."
    In full manual mode EC affects nothing except "when" the meter tells you the exposure is correct. The actual exposure is determined by the settings. What the meter looks like in this situation is very dependent on camera make/model.

    In manual mode with auto ISO enabled the camera will change the ISO to get the "correct" exposure based upon the EC setting (Nikons and newer Canons).

    In an auto mode (A/S) the camera will change whatever it has control of to obtain the "correct exposure based upon the EC setting.

    On Nikons in A mode with auto ISO the camera will change the ISO first (based upon the menu settings) and then start to change SS. In S mode with auto ISO Nikons will change the aperture first until it hits the limit, and then it will change ISO.

    Basically, what EC does is tell the camera meter "where" the correct exposure is. For EC to be applied, the camera must have control of a relevant setting (ISO/A/SS)
    Last edited by sk66; 01-21-2013 at 07:13 PM.

  8. #18
    ZafarSami's Avatar
    ZafarSami is offline dPS +1000 Club
    Join Date
    Nov 2012
    Posts
    6,723

    Default

    Thanks Steve. Got it. Manual mode exposure compensation just adjusts the viewfinder metre's centre point, while in A/S modes will it will apply less or more exposure as you choose compared to the camera calculation.
    Zafar
    Nikon D300s, Nikkor 50mm F1.4G, Tamron SP 24-70mm F2.8 VC, Tokina 11-16mm F/2.8, Tamron SP 70-200mm F2.8 VC, Nikkor 18-300mm F3.5-5.6, Nikon SB 900
    Flickr http://www.flickr.com/photos/zafarsami/

  9. #19
    RichardTaylor is online now dPS +1000 Club
    Join Date
    Nov 2009
    Location
    Sydney, Australia
    Posts
    7,912

    Default

    Thanks Steve.

    ------------------------

    Quote Originally Posted by ZafarSami View Post
    Thanks Steve. Got it. Manual mode exposure compensation just adjusts the viewfinder metre's centre point, while in A/S modes will it will apply less or more exposure as you choose compared to the camera calculation.
    This will be camera dependant, as Steve says.
    Last edited by RichardTaylor; 01-21-2013 at 08:25 PM.

  10. #20
    Darren C is offline Used to be shruggy63
    Join Date
    Mar 2012
    Location
    Manchester, England
    Posts
    589

    Default

    Thanks for this! Very informative thread with really nice pictures. They illustrate the points perfectly.
    Right! I'm off to look at ways to weatherproof my camera so I can head out in the rain.

Page 2 of 3 First 123 Last

Posting Permissions

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

Log in

Log in