can I always trust the histogram on white birds?

I have often taken pictures of white birds where the histogram looks good yet the whites are "overexposed". this is a recent example:

there was no clipping of the histogram in my camera or in photoshop and no blinking highlights in my camera, yet i feel parts of this bird are overexposed and there is detail lost especially along the top of the bird. Or is there some other reason for the loss of detail such as subject distance? If you agree that the whites look overexposed, why did it not appear so on the histograms?

image underwent no pp except for conversion to small jpeg from original raw image.

cloudy day, 3 hrs after sunrise, with the sun behind me.

thanks for your help

phil

d3, 300/2.8 + 1.7X, 1/640 @ f/7.1, ISO 400, fill flash at -2.0.

Hi Phil, I find that the highlight warning on my Canon 1D series will blink even when I have in fact not blown a highlight.
Helps to spot meter these birds and open up from there.

Your image here(with fill flash) looks good to me, maybe a bit flat, but nothing hot.
PP should be easy here.

this is a sample showing you brightest areas via a threshold layer....the brightest is a 248 white. I did not check the individual channels. You did a nice job. And egrets are strange, there really is little to no detail to be had in "some" areas......from a distance

Phil you might try setting the camera in sRGB It will give you a better warning with over exposure.

Your exposure looks good. Just need softer light for the white birds !! I would trust the highlight alert Much easier to see !!!

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Originally Posted by Phil Seu

I have often taken pictures of white birds where the histogram looks good yet the whites are "overexposed".

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Overexposed is different than detail less. Here is an older thread on the subject:

http://www.birdphotographers.net/for...ead.php?t=8197

Quote:

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Originally Posted by Phil Seu

image underwent no pp except for conversion to small jpeg from original raw image.

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This could be the reason as Adobe raw convertor defaults are +25 brightness and +50 contrast. Unless you have the controls set up this is could be the reason.

Robert

Robert,

thanks for the link. i have a major headache now but did learn a lot.

phil seu

If you are talking about the histogram and highlight alert in camera, keep in mind that the camera is showing you a small jpeg that is generated from the raw file. The histogram and highlight alert are using the generated jpeg as well. This means that camera settings that affect the jpeg, but not the raw file, need to be considered. For example the contrast setting may produce blown highlights when there are not any blown highlights in the raw file. I set me contrast to low to avoid most erroneous blinkies and histograms.

Quote:

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Originally Posted by Jim Neiger

If you are talking about the histogram and highlight alert in camera, keep in mind that the camera is showing you a small jpeg that is generated from the raw file. The histogram and highlight alert are using the generated jpeg as well. This means that camera settings that affect the jpeg, but not the raw file, need to be considered. For example the contrast setting may produce blown highlights when there are not any blown highlights in the raw file. I set me contrast to low to avoid most erroneous blinkies and histograms.

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Great point, Jim. I set mine to Adobe RGB and contrast is very low in the user-defined jpg setting. The sharpness setting is quite high so I can really see at the back LCD screen whether an image is sharp or not.

I find that "Contrast" set to its lowest level, -4, on the Canon 5D produces highlight-alert flashes very close to what is occurring with the Raw file data exposure level.
As to picking up proper warnings on white birds/objects within the frame... depends on how much of that white image fills the frame; in your exampled close image the highlight warning will tell the tale. But if the bird or birds are far more distant... blown highlights are almost inevitable, i.e., the physical white size too small to be adequately be picked up by the pixel warning sensor.

Setting the in-camera contrast to -2 will allow you to more closely approximate in exposure the tonal/dynamic capture range of your sensor, while pushing the whites to the very edge without blinking highlights or losing detail. It should be noted that the resultant image when viewed in RAW will most often appear with very bright, but not clipped whites. REST ASSURED ALL THE HIGHLIGHT DETAIL IS THERE. You need only selectively draw out the highlight detail in RAW conversion or CS3. The benefit is that this is all accomplished without sacrificing shadow detail.

Best,

Chas

Great thread! thanks a lot for the information guys:)