Forums
New posts
Search forums
What's new
New posts
New media
New media comments
New profile posts
Latest activity
Media
New media
New comments
Search media
Members
Current visitors
New profile posts
Search profile posts
Log in
Register
What's new
Search
Search
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Learning
Photography Q&A
Newbie question about picturing in sunlight
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="WayneF" data-source="post: 405222" data-attributes="member: 12496"><p>Sorry to say that it is really too late now. The correct time is in the field when taking the picture, with opportunity for a second corrected try.</p><p></p><p>As we increase camera exposure, the histogram data is shifted right, to be brighter. But when the value hits the right edge at 255, it cannot go higher. So it just piles up in a tall spike there at the right edge, at 255. Maybe it ought to be 260 or 270 or more, but digital numbers simply cannot store brighter than 255. This is called clipping, the 270 data is clipped to be only 255. The color is modified, perhaps only in the red channel. And if red is modified independently of blue and green, this changes the color. And that additional (excessive) exposure is gone now, no way now to know what it should have been. It cannot be restored. The solution is another picture with a more careful exposure.</p><p></p><p>There are photo editor tools that will reduce the red level, like 255 to be only 245. But that leaves a gap between 245 and 255... There is no way to restore clipped colors. Sometimes the colors can be faked there, to look some more desired way.</p><p></p><p>So... clipping is an extremely important thing to watch when taking pictures. If our exposure is simply off a bit, too dark or maybe too bright, we can often just shift it more appropriately. But not if it has been clipped, it is gone now.</p><p></p><p>This is why the camera shows the histogram, so we can check it then and there. We typically do want the data to extend generally high there (near the right border), but touching it, and actual clipping is really the only thing of interest. Lack of Clipping is extremely important to verify. But watch the three RGB channels, and NOT the gray single histogram (which shows nothing).</p><p></p><p>We can set the camera rear LCD image view to blink on overexposed (clipped) areas, but we can only set one of the red or green or blue channels. Red seems a good choice, but bright blue and green can also clip. Setting blinkies in the single gray channel is pointless, the one gray channel is something very different, not of interest.</p></blockquote><p></p>
[QUOTE="WayneF, post: 405222, member: 12496"] Sorry to say that it is really too late now. The correct time is in the field when taking the picture, with opportunity for a second corrected try. As we increase camera exposure, the histogram data is shifted right, to be brighter. But when the value hits the right edge at 255, it cannot go higher. So it just piles up in a tall spike there at the right edge, at 255. Maybe it ought to be 260 or 270 or more, but digital numbers simply cannot store brighter than 255. This is called clipping, the 270 data is clipped to be only 255. The color is modified, perhaps only in the red channel. And if red is modified independently of blue and green, this changes the color. And that additional (excessive) exposure is gone now, no way now to know what it should have been. It cannot be restored. The solution is another picture with a more careful exposure. There are photo editor tools that will reduce the red level, like 255 to be only 245. But that leaves a gap between 245 and 255... There is no way to restore clipped colors. Sometimes the colors can be faked there, to look some more desired way. So... clipping is an extremely important thing to watch when taking pictures. If our exposure is simply off a bit, too dark or maybe too bright, we can often just shift it more appropriately. But not if it has been clipped, it is gone now. This is why the camera shows the histogram, so we can check it then and there. We typically do want the data to extend generally high there (near the right border), but touching it, and actual clipping is really the only thing of interest. Lack of Clipping is extremely important to verify. But watch the three RGB channels, and NOT the gray single histogram (which shows nothing). We can set the camera rear LCD image view to blink on overexposed (clipped) areas, but we can only set one of the red or green or blue channels. Red seems a good choice, but bright blue and green can also clip. Setting blinkies in the single gray channel is pointless, the one gray channel is something very different, not of interest. [/QUOTE]
Verification
Post reply
Forums
Learning
Photography Q&A
Newbie question about picturing in sunlight
Top
