gray cards

Discussion in 'Beyond the Basics' started by tron, Mar 31, 2009.

  1. tron

    tron TPF Noob!

    Joined:
    Apr 26, 2008
    Messages:
    352
    Likes Received:
    6
    Location:
    Michigan
    Can others edit my Photos:
    Photos NOT OK to edit
    so ive been getting a lot of blown out skies lately (even while using polarizer filters and nd filters).

    i read that it might have to do with the cameras metering abilities, so i was thinking if i meter and lock off an 18% grey card will it help even out my exposure? right now im using my camera as a light meter and spot metering to see if theres too much contrast between my highlights and shadows. if there is i try to use an nd2, nd4, or nd8 filter. would it justbe more effective to use a grey card?

    thanks
     
  2. Garbz

    Garbz No longer a newbie, moving up!

    Joined:
    Oct 26, 2003
    Messages:
    9,713
    Likes Received:
    203
    Location:
    Brisbane, Australia
    Can others edit my Photos:
    Photos NOT OK to edit
    You are using these filters how? ND filters just make things darker and doesn't help with the contrast situation at all. Are you talking about an ND Grad filter?

    Also the grey card won't help much here. This is a dynamic range problem. If the sky is sufficiently bright compared to the subject it will blow out unless you under expose. A grey card is often more useful for perfectly exposing skin tones.

    Consider taking multiple exposures and combining them in photoshop, or get an ND grad filter, or consider doing a *gag* HDR.
     
  3. Torus34

    Torus34 No longer a newbie, moving up!

    Joined:
    Jan 26, 2006
    Messages:
    2,117
    Likes Received:
    37
    Location:
    Tottenville, Staten Island, NYC USA
    Can others edit my Photos:
    Photos OK to edit
    If your rig can provide an exposure histogram [and if you are taking shots which provide you with the luxury of enough time to use it,] you can see quite easily if you have a 'blown-out sky' problem and correct as required.
     
  4. tron

    tron TPF Noob!

    Joined:
    Apr 26, 2008
    Messages:
    352
    Likes Received:
    6
    Location:
    Michigan
    Can others edit my Photos:
    Photos NOT OK to edit
    i am using a gradual neutral density filter i forgot to saay that.

    and i dont get why sometimes my skies look awesome and other times they look like crap.

    example: i was really happy with the skies in this pano i did
    [​IMG]

    example2: heres some crappy skies
    [​IMG]

    i dont get it haha
     
  5. Garbz

    Garbz No longer a newbie, moving up!

    Joined:
    Oct 26, 2003
    Messages:
    9,713
    Likes Received:
    203
    Location:
    Brisbane, Australia
    Can others edit my Photos:
    Photos NOT OK to edit
    Easy. In the first picture you're exposing for the highlights. The white part of the building on the right is well exposed and thus much brighter than the dark blue sky.

    In the second picture you're exposing for the shadows. The cars are in the shade and simply sooo much darker than the sky so the sky will blow out. There's only so much dynamic range you can capture on a digital sensor and unfortunately it's less than half of the capabilities of the human eye.

    Up the ND grad to 4 stops or more, and or do multiple exposures one dark enough to get the sky blue and combine them in photoshop or HDR them.
     
  6. bdavis

    bdavis TPF Noob!

    Joined:
    Jan 14, 2009
    Messages:
    784
    Likes Received:
    3
    Location:
    Iowa
    Can others edit my Photos:
    Photos NOT OK to edit
    *Claps* Bravo!

    Come to think of it, I need to pick myself up some ND Grad filters...
     
  7. tsaraleksi

    tsaraleksi TPF Noob!

    Joined:
    Jun 12, 2007
    Messages:
    1,045
    Likes Received:
    0
    Location:
    Greencastle Indiana
    Can others edit my Photos:
    Photos NOT OK to edit
    If the sun is behind you at something other than midday, retaining skies will be easy. If not, it's going to be nigh well impossible (see the second picture), though maybe if could be done with some sort of ND filters-- I've not much experience with filtration.
     
  8. henryp

    henryp TPF Noob!

    Joined:
    Jan 21, 2007
    Messages:
    175
    Likes Received:
    12
    Location:
    New York, NY
    Can others edit my Photos:
    Photos NOT OK to edit
    Meters Don't See 18% Gray
     
  9. JerryPH

    JerryPH No longer a newbie, moving up!

    Joined:
    Oct 14, 2007
    Messages:
    6,111
    Likes Received:
    15
    Location:
    Montreal, QC, Canada
    Can others edit my Photos:
    Photos NOT OK to edit
    People still make the mistake of confusing the primary function of a grey card (which is used to set white balance) as an object to set exposure from.

    Set your exposures using histograms or light meters. Set your white balance using grey cards. Once the WB is correct, and you shoot a grey card in the light that you want, the fact is that if your camera is set up to use 12% or 18% (a small shift to the left or to the right on your histogram), will make no great difference in the outcome of the photo. The height of the peak of the histogram or the external meter (which should be darn near identical) is what you reference to set the camera settings to for "proper" exposure. "Proper" meaning technically proper, not artistically, which can vary drastically.

    Let's toss in another factor that many photographers who use an "old school" film technique and try to expose to the right. What they are doing is on purpose telling the camera to meter properly for a DARKER shade of grey to bring out detail in the shadows and hopefully not blow out the highlights. The effectiveness of this technique varies between cameras, meters, the scene and the photographer. Me, personally, I am no great fan of this technique. The dynamic range of a camera is likely well able to to support this technique under ideal conditions and if set up properly (ie highest quality 14-bit RAW settings), but when one shoots in darker place, is forced to raise ISO, that dynamic range "leeway" that we must have to save the highlights, disappears and is gone... and we easily lose data in an unrecoverable fashion in parts of the picture that we need.
     
    Last edited: Apr 3, 2009
  10. henryp

    henryp TPF Noob!

    Joined:
    Jan 21, 2007
    Messages:
    175
    Likes Received:
    12
    Location:
    New York, NY
    Can others edit my Photos:
    Photos NOT OK to edit
    Grey cards have been around for decades, long before the first digital camera was conceived. I don't recall ever worrying about white balance when Tri-X was my primary recording medium, but there was a grey card in my kit back then, as there is now.
     
  11. JerryPH

    JerryPH No longer a newbie, moving up!

    Joined:
    Oct 14, 2007
    Messages:
    6,111
    Likes Received:
    15
    Location:
    Montreal, QC, Canada
    Can others edit my Photos:
    Photos NOT OK to edit
    It is not a matter of worry... today, way after Tri-X has come and most places almost gone, digital permits the ability to adjust white balance in camera on the fly, something that with film was impossible to do. That is a great convenience to not need to worry about it in post process, though if one shoots in RAW, it is childishly simple to adjust.

    That was my point... that the grey card's forte or strong point today is for the setting of white balance... not so much exposure (though it can, but then you are metering for the card, not the scene). "Correct" exposure means different things to different people (film or digital), from the "technical" style where the external light meter or camera exposure meter or histogram is used, to the artistic... where the technicalities fall to the way-side in favor of the photographer's preferences. :)
     

Share This Page