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Just after some clarification on what is and is not considered acceptable.  Obviously, it is perfectly normal for parts - even large parts - of an image to be out of focus so long as the subject is pin sharp and the depth suits the picture.  How much importance is attached to CA in the out of focus areas - that is probably related to them being out of focus.  I have part of a tree in a planter in front of a thin structure.  The planter, trunk and centre leaves are sharp and no CA - however the leaves further away and reaching outside the shadow of the structure do have quite significant colouration haloing, as do branches.  Now ordinarily for putting on Flickr or something, I would not worry as I believe the issue is due to focus point - but for Alamy I am just after some guidance.

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I believe CA is an automatic fail. I use DxO Photolab which is magical in correcting errors like CA, but I think that Lightroom also has sliders for CA. I am sure a LR user can weigh in here and confirm this. 

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I'm no expert in these subjects, but I believe that the colour "haloing" that you mention is not considered to be CA. I've never had any QC problems with it.

 

Edited by John Mitchell

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Opposite viewpoint. Several years ago I had an image with trees in it against a bright sky, not the subject. I missed a bit of CA in the top left corner. It was minuscule to the rest of the image. I got a fail for CA. 

Now, consider the fact that I was using a particular camera (an approved one, maybe a bad copy, and had received a few fails for soft and lacking definition. Because of those fails, everything I submitted was under intense scrutiny by QC. I pictured them not only inspecting at 100%, but then using a huge magnifying glass on top of 100%. Paranoid, yes.  Who knows if they would have failed me now, with a great QC rating for several years, shooting with mirrorless.

Of course I got rid of that camera, a Nikon. (No, not the D800, but it’s history also).  I became much more discerning about my own QC.

Betty

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26 minutes ago, Betty LaRue said:

Opposite viewpoint. Several years ago I had an image with trees in it against a bright sky, not the subject. I missed a bit of CA in the top left corner. It was minuscule to the rest of the image. I got a fail for CA. 

Now, consider the fact that I was using a particular camera (an approved one, maybe a bad copy, and had received a few fails for soft and lacking definition. Because of those fails, everything I submitted was under intense scrutiny by QC. I pictured them not only inspecting at 100%, but then using a huge magnifying glass on top of 100%. Paranoid, yes.  Who knows if they would have failed me now, with a great QC rating for several years, shooting with mirrorless.

Of course I got rid of that camera, a Nikon. (No, not the D800, but it’s history also).  I became much more discerning about my own QC.

Betty

 

Same here. I once opened up the shadows too much in an image and it failed QC because of a smidgen of CA in the shadow areas. However, it it was the typical red-cyan variety of CA. Starsphinx could be talking about something else. The haloing might be due to lens coating or some other optical peculiarities of some lenses. For instance, I see a lot of colourful "haloing" in some images captured with old manual focus lenses. The lens coatings were different back when they were manufactured. However, I also sometimes see it with newer lenses, especially in close-ups of plants where there are big out-of-focus areas with a lot of colour (leaves, petals, etc.). Actually, it can be quite pretty. At least QC seems to think so. B)

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I've got CA removal as a default in LR, but, occasionally, and particularly with wide angle lenses, I have to intervene and make a further manual adjustment within that program. Very occasionally that isn't enough, and I've had to carefully clone out the CA in PS - or abandon or crop  the shot. 

 

One nearly slipped through the net yesterday, backlit window frames high up in a building, slightly overexposed. I always check skies at 100%, but detailed shots I tend only to check that the principal features are sharp, however, for some reason, I strayed high and saw the CA.  Phew.....

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It may be back lighting to the leaves/branches - it is purply violet and directly related to where the branches extend out beyond the structure it is in front of.  I am going to err on the side of caution and not upload it - I was hurried and tired when I took it and I could do better.  I will put it on a sharing site and link it so people can look.

 

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Just realized that image cannot be properly zoomed in so this is a crop showing the detail 0327%20-%20chippenhampark%20v%20ashton%2

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That is bad lateral CA so you should not submit that. As Brian says, the CA tick box usually deals with CA effectively but not always. This can happen at the edge of the frame with wideangle lenses and you should be able to deal with that using the additional Manual Defringe adjustment in Lightroom under Lens Corrections. If you don't already have the CA button ticked by default, then you should definitely do that. I don't know why Adobe don't do this as an app default as it is magic in most situations.

 

EDIT - why not put the raw on Dropbox. I don't know if any other sites allow raws.

Edited by MDM

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3 minutes ago, MDM said:

That is bad lateral CA so you should not submit that. As Brian says, the CA tick box usually deals with CA effectively but not always. This can happen at the edge of the frame with wideangle lenses and you should be able to deal with that using the additional Manual Defringe adjustment in Lightroom under Lens Corrections. If you don't already have the CA button ticked by default, then you should definitely do that. I don't know why Adobe don't do this as an app default as it is magic in most situations.

 

EDIT - why not put the raw on Dropbox. I don't know if any other sites allow raws.

I do have the CA ticked by default (although have just had an upgrade so will double check as I missed sharpening going from 25 to 40 for ages).

I am not too concerned about this photo,  just a chance what if of something that caught my eye.  It was actually taken with a sigma 70-300mm which can be bloody awful on out of focus bits.  Most of the stuff I do is football and nature - I need the 300mm.  However, it is a bottom of the market lens and replacing it is top of my list of where any money I have spare is going.  That said it will still do the job under the right conditions - most of the photos I have on here were taken with it.

I do not currently have Dropbox - I am investigating it, as given a couple of months I hope to be able to dedicate a lot more time to shooting and uploading, and am going to be after as much advice as I can get.  I will also be spending a lot of time properly learning Lightroom - although I will probably still stick with the proviso if something takes serious fiddling to look right then it is not good enough in the first place - at least for Alamy.

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That's "purple fringing" by the looks of it. Usually easily removed. I find that DxO (see Colin's post above) deals with it well. Not doubt LR and other software does as well.

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This is probably not CA. It just looks like CA 

 

When you have a sharp transition between a darker leaf or branch and a brighter sky sometimes the sensor pixel hit by blue sky brightness, will add some blue brightness to the pixel hit by darkness next to it on the sensor. Bright blue sky over green leaf or black branch, results in purple fringing not CA. Particularly in the corners because the light is striking the corner pixels at a more oblique angle. It is the camera electronics. I think this is purple fringing.

 

It could be a ghost reflection from the sensor cover plate.

 

It could be a ghost reflection from the UV filter if you have one on the lens.

 

It could also be general lens flare.

 

So Quality high megapixel camera, quality low flare prime not zoom lens, lens hood, no filter on lens, if you want perfection.

 

I would submit it regardless.

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I wouldn't submit it in its present condition, but I'm not as brave as Bill. B)

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I will give this one a miss - I would rather reject stuff that might pass than risk failing QC.   I am not yet confident in my ability to accurately judge the line so try and stay well clear of it.

 

 

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If you're using LR, and have the default CA boxes checked, use the manual adjustments.   If it's CA, they will at least try to remove that.  If they change the purple, it's CA, even if they don't remove it.    Even if it's not CA, it really doesn't look so great.

 

Though this is not an example, there are some bushes (in my neck of the woods) that actually have purple stems.  That can get your attention!

 

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I will have a good play with the image in Lightroom and see what I can do making it better/worse.  Seeing what happens and hopefully learning something.

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+1 for DxO, PhotoLab2. I never learned how to handle CA while using PSE (10 years), but got by somehow. With PhotoLab2 I never see it and have never had to adjust it. The lens profiles are great and the CA dialog has a check box for purple fringing, which I haven't had to use (2 Canon zooms, 2 Canon primes). Free trial would probably fix this image on auto, if there is a lens profile for your lens.

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3 hours ago, Starsphinx said:

I do have the CA ticked by default (although have just had an upgrade so will double check as I missed sharpening going from 25 to 40 for ages).

I am not too concerned about this photo,  just a chance what if of something that caught my eye.  It was actually taken with a sigma 70-300mm which can be bloody awful on out of focus bits.  Most of the stuff I do is football and nature - I need the 300mm.  However, it is a bottom of the market lens and replacing it is top of my list of where any money I have spare is going.  That said it will still do the job under the right conditions - most of the photos I have on here were taken with it.

I do not currently have Dropbox - I am investigating it, as given a couple of months I hope to be able to dedicate a lot more time to shooting and uploading, and am going to be after as much advice as I can get.  I will also be spending a lot of time properly learning Lightroom - although I will probably still stick with the proviso if something takes serious fiddling to look right then it is not good enough in the first place - at least for Alamy.

 

Dropbox is just a cloud storage facility and free up to 5GB I think but it does allow you to upload raw files unlike a lot of other ones. The fringing is bad for sure but it would be interesting to see if it can be fixed which is why ai suggested Dropbox. I have a high end Nikon 24-70 lens that shows similar green purple fringing at extreme edges when shooting wideangle against bright backgrounds like this and can be fixed using the eye dropper tool in the Defringe section of Lightroom. It is nothing like as intense as in your pic but is very similar in quality. 

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13 hours ago, Starsphinx said:

I will have a good play with the image in Lightroom and see what I can do making it better/worse.  Seeing what happens and hopefully learning something.

 

I often have to use the manual adjustment to get rid of purple fringing on branches against a sky, particularly on the NEX6. It does the job very easily and I've submitted many pics to Alamy that were processed in that way.

 

Alan

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I wouldn't submit an image like that, especially as it should be an easy fix in LR.

 

Mark

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 Definitely purple fringing not really CA.

 

There is a tool in LR which can get rid of that easily.

 

Allan

 

 

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I have had a play and cleaned it up quite considerably - I will put the improved version up in a bit - possibly tomorrow as getting ready for a game I am shooting.

 

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I have used the Defringe slider very successfully on images such as this when I have used my Canon 70-250 at the high end of the lens.  Defringe slider works a wonder.

 

Jill

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