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<blockquote data-quote="WayneF" data-source="post: 202346" data-attributes="member: 12496">Sorry, I dont know about Lightroom, I use Photoshop instead.&nbsp; Photoshop Levels (and curve too) have a menu for RGB, or individual R or G or B channels.&nbsp;&nbsp; But the camera can show individual channels, and individual is the only choice that has any meaning in a camera.The composite luminosity histogram is about gray scale levels, and would have meaning for a gray scale image.&nbsp; But for a color image, it is just a hypothetical numerical manipulation, and does NOT show real data.Set up your umbrella in same way at same distance from a mostly white plain wall, and take a picture.&nbsp; Blank so you can see variations. Not too bright, though, don't burn it all out at 255, to be indistinguishable, but leave some meaningful data you can inspect for differences.&nbsp; TTL metering a white wall ought to come out about one stop down, which is good for this.And try another similar picture with sister, but back off on the exposure some - try it once.&nbsp; Even the individual three channels should NOT be pegged at 255...&nbsp; Faces are not 255 white.&nbsp; Include a white shirt or white paper in the test scene (at same subject distance) to see the difference.&nbsp; <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile&nbsp; &nbsp; :)" loading="lazy" data-shortname=":)" /></blockquote>

[QUOTE="WayneF, post: 202346, member: 12496"] Sorry, I dont know about Lightroom, I use Photoshop instead. Photoshop Levels (and curve too) have a menu for RGB, or individual R or G or B channels. But the camera can show individual channels, and individual is the only choice that has any meaning in a camera. The composite luminosity histogram is about gray scale levels, and would have meaning for a gray scale image. But for a color image, it is just a hypothetical numerical manipulation, and does NOT show real data. Set up your umbrella in same way at same distance from a mostly white plain wall, and take a picture. Blank so you can see variations. Not too bright, though, don't burn it all out at 255, to be indistinguishable, but leave some meaningful data you can inspect for differences. TTL metering a white wall ought to come out about one stop down, which is good for this. And try another similar picture with sister, but back off on the exposure some - try it once. Even the individual three channels should NOT be pegged at 255... Faces are not 255 white. Include a white shirt or white paper in the test scene (at same subject distance) to see the difference. :) [/QUOTE]

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