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Old Aug 10, 2008, 2:05 PM   #1
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I have been having problems with overexposure of any yellow objectwith my 40Dusing any of my lens, whether it be Canon 60mm macro or 70-200mm f4L. I shoot in RAW. When taking pictures of yellow flowers, or flowers with yellow stamen, the yellows will be washed out, while the rest of the picture is perfectly exposed. I can adjust the exposure in photoshop to compensate the yellows, but end up with a very under-exposed shotof everything but the yellow portion. Has anyone else experienced this. Could the sensor be at fault.:?




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Old Aug 10, 2008, 2:19 PM   #2
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What metering mode do you use? Can you post an example? There are all sorts of yellow :-), may be one of them fools the camera's metering into overexposure (especially if this is a bright/pale yellow). The camera's meter is calibrated for 18% grey (or is it 12% in DSLRs?), so any brighter colour if it takes most of the frame will fool the metering. You can compensate by setting an exposure compensation on camera.
I can be completely wrong here as well.
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Old Aug 10, 2008, 3:08 PM   #3
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I have been using evaluative metering. The problem occurs with mostly, as you say, pale or bright yellows. This is an example taken in subdued sunlight.
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Old Aug 10, 2008, 4:56 PM   #4
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Since the evaluative takes from the whole scene and the yellow is a minor portion, then the camera is choosing from what most of the scene is metered at. You could use partial or spot to do better metering for a specific item(especially in high range photos). It doesn't look like's it's that bad or that the flowers are blown out. Is the histogram showing blown highlights?

Also, it looks like the flowers look soft because of the DOF and the focusing of the rock. This could make the flowers look like their overexposed due to not seeing any detail.
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Old Aug 10, 2008, 6:50 PM   #5
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Thank you for your input. I will try changing to spot metering next time to see if that helps. I must confess to bring illiterate when it comes to using histograms. Here is a corrected version of the same photo. I don't believe focus is the problem. I don't recall having the problem with my previous camera, a Canon xti.
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Old Aug 10, 2008, 6:54 PM   #6
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Thank you for your input. I will try changing to spot metering next time to see if that helps. I must confess to bring illiterate when it comes to using histograms. Here is a corrected version of the same photo. I don't believe focus is the problem. I don't recall having the problem with my previous camera, a Canon xti.
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Old Aug 10, 2008, 8:53 PM   #7
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Those really don't look bad to my eyes. But, if you're seeing a consistent issue, my guess is that you changed your color space from sRGB to something else with your raw converter, since my EXIF viewers are showing an unknown color space for your samples. But, that may just be because Picasa (which is what it looks like you used to downsize the images) stripped out and/or modified the EXIF data.

What software are you using for raw conversion (I'm assuming Adobe Camera Raw since you mentioned Photoshop), and are you using sRGB color space?

If you're using something other than sRGB, the browser you're using must be color space aware for colors to look right (and most browsers are not). Most raw converters have a variety of contrast curves to choose from, too (so, a setting there could cause issues).

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Old Aug 11, 2008, 10:37 PM   #8
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Thank you Jim. I am using Photoshop Elements and had the color set to RGB for printing. I switched back to sRGB, but noticed no difference in appaerance.
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Old Aug 22, 2008, 7:24 PM   #9
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i have to agree with kalel33, "Also, it looks like the flowers look soft because of the DOF and the focusing of the rock. This could make the flowers look like their overexposed due to not seeing any detail."
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