Noticing allot of noise and red color in Canon photos upon import
Upon importing my images I see red spots all over my images. This doesnt seem to be happening on other Editing tools I have on Mac but only on Capture one. Can anyone please explain me why would this happen?
This picture hasnt been edited by any tools and yet I see this in Capture one. I dont see this however in other tools I own. Can someone please explain me what is causing this? How can I get rid of this?
Thanks
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Looks like your highlight alert is set lower than in your other tools. Have a look at your Exposure preference settings.
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The red spots are alerts that you've clipped or almost clipped highlight. You can toggle the alert on/off using the keyboard (cmd-E) or from the menu View -> Exposure Warning. You may also have this icon in your toolbar:
If so you can click on it to turn warning on and off. Finally, in preferences under the Exposure tab you can also enable Shadow warnings. They will show up as blue when exposure warnings are enabled and you've clipped your blacks.
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So what does it mean I have higher than usual exposure and I should be reducing the exposure? Or its just a warning and safe to ignore? Any general rule of thumb around the exposure?
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It's a warning of Capture One and if you print it, the red tint will not be printed, but you'd see blown out highlights. With "Other Editing tools" you're referring on other apps, I guess?
You can change the limit of the "blown out highlight" (red in my sample) and "too dark shadow" (blue) warning.
This setting leads to this regions of "blown highlights" and "dark shadows":
And beside the ways Marco Hyman already described to toggle this warning ON and OFF, there's also an icon:
In the case of your picture, you can either reduce the exposure or in the HDR panel the highlights
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I add that, as far as I understand, sometimes the red warnings appear at the borders of transitions areas in form of thin lines, specially if you have high sharpening. For instance, I often I see them at the border of foliage or branches against the sky - while the sky itself is ok. I think it makes sense thinking of how sharpening algorithm are made and shouldn't have any real impact on the photo (I can't bet all my money on it because I seldom print my photos (sigh)).
Example attached (1:1 crop).
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Fabrizio,
I am surprised red warnings appear at the borders of bright/dark transitions, with nothing else in the sky, except if they were related with chromatic aberrations. Did you check them ? It is possible to suppress (or at least reduce) them using the appropriate tool in Capture One.
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As you can guess, there's CA in that kind of shot, but CA correction is already active and it reduces the problem but with remaining traces (see attachment below with red warnings disabled), even though you need to pixel peep to really notice.
If you look carefully you can also see trace of a halo, that is probably due to Clarity + Sharpness (they are set to very high values here, around 70). If I reset them to zero only a handful of sparse red warnings appear (see this second attachment), while CA is still evident. So I think is more a problem of Clarity / Sharpness than CA.
BTW, applying CA correction slightly increases red warnings.
tbd
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Thanks Fabrizio for the details ! You are pushing C1 to its limits ! I am sure nobody would guess any CA in your image if it were not zoomed at 100%......
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In fact if you didn't ask me I wouldn't even care of it... At normal size the image is fine. Now, as I said, I haven't printed a photo for years, but I doubt it would be really noticeable in a reasonably sized print.
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So what does it mean I have higher than usual exposure and I should be reducing the exposure?
Answering the second part of this question, should you reduce exposure. As is often the case, it depends. In the image you posted a slight reduction of exposure might be justified. But first check the actual exposure values at the indicated locations. I believe the default setting is for Capture One to indicate when highlights exceed 250 of the 255 max value. Your image might read 253 or 254 at the indicated locations. In that case the exposure is fine. Nothing is blown out. If the value is 255 you've lost data. Then the question becomes is that data important to you? At the edge of clouds the answer might be no.
Another place you will see the red indication (when you turn it on) are areas of specular highlight. A good example might be reflections of the sun off of chrome trim. With specular highlight there was never any data for you to capture in the first place. Accept the blown out areas or re-take the image from a different angle in an attempt to minimize them.
In any case, it's a tool that can be used. Or not. If the warnings bother you turn them off.
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You can move the mouse and read the RGB values on top, or add a color readout (see below cursor tool).
If the values for RGB are the same, e.g. 253,253,253, then there is no data and reducing the exposure (or any other pull down on any other slider) will only make it grey, e.g. 250,250,250 or 230,230,230. In this case you gain nothing, a pure white looks better than a pure grey, imo.
Note that the red warning (if enabled) will show up even if only one color is above the configured limit, so 252,255,230 might give you a warning, though one can argue that some pixel neighbors have a different value in one of the non-clipped colors, e.g. 254,255,236, and hence you see a difference/structure in this area. Not blown out, if you ask me, maybe a color shift only (because one channel e.g. the green channel clipped). Reducing the exposure or HDR highlight would probably not solve the color shift, not a big problem though as you can correct this with local WB or by other means, if really need be (which I haven't noticed yet).
In your image (clouds) I would probably pull down a white slider in the HDR tool a bit, removing the majority of the red warning, probably not even completely.
Last but not least it depends also on some artistic, subjective considerations, imo. Technical "perfection" is not always the most important thing. Reducing exposure or highlights/whites always have an impact on other areas (to preserve a somewhat smooth transition) which usually has an effect on the overall tonality distribution and appearance of the image and this can result in a less attractive image than with some parts a little bit blown out.
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