|Quoting Eadster (Reply 13):|
I'm not understanding where Anet come from with contrast rejections sometimes.
The rejection text is actually a pretty good description of the problem but the two examples Bjorn gives here are fairly representative of one extreme of the commonest problem. Sebastian was evidently being a little sarcastic, humourous, but he was also making a point. Look at the starboard undercarriage and, yes, that is there, but what about the tyres ? They have disappeared into the shadows and it is that that causes me to agree with the contrast rejection. The dark rejection ? I am not sure that I agree with that part though sometimes just brightening an image can restore that shadow detail. It maybe justified and the two often go together as it can be difficult at times to separate the problems without changing them.
In good old-fashioned photographic terms, not airliners.net rules, generally
1, Every image should have a pure black
2, Every image should have a pure white (failing on 1 or 2 leaves flat, muddy images)
3, Details should be held into the shadows and highlights (neither blocked up)
Bjorns fails on the last point with no detail being held into the shadows = valid contrast rejection.
No 1 is by far the commonest rejection reason where images have weak, smoky looking blacks that are effectively a very dark grey. If levels are opened on these images (Ctrl+L) there is usually a gap on the left of the histogram and moving the left slider in corrects the problem. If an image of mine shows the problem I move the left slider in whilst watching the blacks and stop at the point the blackest part loses its smokiness.
Incidentally, images with weak contrast tend to appear softer and those with high contrast tend to show oversharpening more so getting the contrast correct is a very important stage of getting your image right.
I hope this helps