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Thread: Overexposure issue?

  1. #1

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    Gary

    Overexposure issue?

    Hello,

    I have been out and about in the early morning making some images. If the conditions are right then early morning dew can form on objects. As an example on spider webs, plant leaves, grass etc. With the sun being fairly low this can cause them to sparkle when the sun catches them. I have been trying to make images with this in mind. In effect this has meant making images with the sun in front (backlighting?). Although, the images seem fine. When I get them back to look at in PP the edges of the water drops/dew are overexposed and get highlighted when I check for overexposure/blown highlights.

    Bearing in mind that I am using a Canon G2 for which I have not got filters. Is there a way round this problem? or perhaps it's not a problem? If I could use a filter would a polarizing one work? Anyway, I would be interested to hear your thoughts. Thanks.

    Cheers for now

    Gary

  2. #2

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    Re: Overexposure issue?

    Quote Originally Posted by oldgreygary View Post
    Hello,

    I have been out and about in the early morning making some images. If the conditions are right then early morning dew can form on objects. As an example on spider webs, plant leaves, grass etc. With the sun being fairly low this can cause them to sparkle when the sun catches them. I have been trying to make images with this in mind. In effect this has meant making images with the sun in front (backlighting?). Although, the images seem fine. When I get them back to look at in PP the edges of the water drops/dew are overexposed and get highlighted when I check for overexposure/blown highlights.

    Bearing in mind that I am using a Canon G2 for which I have not got filters. Is there a way round this problem? or perhaps it's not a problem? If I could use a filter would a polarizing one work? Anyway, I would be interested to hear your thoughts. Thanks.

    Cheers for now

    Gary
    Hi Gary,

    I suspect that what you're getting are what we call "specular highlights" (similar to the sun bouncing off the chrome bumbers of the proverbial '58 chevvy). The poor old camera doesn't really know what's important in a scene; if it reduced the exposure to protect those highlights then you may well end up with them correctly exposed - but everything else severely under-exposed. A CP filter may help, but a ND filter won't because what you have is a dynamic range issue - and the dynamic range stays the same when you use an ND filter.

    Best suggestion I can think of is just apply some exposure compensation to the shot (either by dialing it in if the camera supports it), or looking at the settings the camera suggests and then dial in some manual ones with a higher shutter speed or smaller aperture. Just experiment.

  3. #3

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    Re: Overexposure issue?

    Thanks for your reply Colin. Yes, the G2 does have exposure compensation and AEB. I have also had problems with skies being 'blown-out'. I have done some brief investigation about HDR. It seems as though by using AEB and creating 3 images, one normal, one at -2EV and one at +2EV these can then be merged using software. I found that Photomatix had a trial version for this purpose. So I tried this on a landscape type image where the sky normally looks 'blown-out'. The result is below. It looks pretty good to me. So, I was thinking that it might possiibly provide one possible solution to my other issue with the dew/raindrops. I will have to see if I can make an image of that before the software trial ends!

    Cheers for now

    Gary

    Overexposure issue?

  4. #4

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    Re: Overexposure issue?

    Gary, there are free HDR programs out there - my favourite is Picturenaut as it's quite competent, doesn't force that really odd tonemapping on you, and the price suits me fine ;o)

  5. #5

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    Re: Overexposure issue?

    Hi Gary,

    Often folks use HDR when the don't need to; in a RAW shot, cameras capture a LOT more information than we can normally see - so the "trick" is to expose for the sky and then rveal the "hidden" detail using the fill light control in post-processing.

    If you do use an HDR program then remember that they stil need post-processing like any other image (after the HDR conversion that is). In your photo above for example it's looking a bit washed out - you need to raise your black clipping point a bit to force some areas to black.

    Overexposure issue?

  6. #6

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    Re: Overexposure issue?

    Both points very interesting Colin. I like the re-worked version. The bit of info. about expose for the sky and then correcting in PP is something that hadn't occurred to me. So that gives another possible option. I will certainly pursue these and look forward to trying them out and see where it takes me. Thanks.

    Cheers for now

    Gary

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