Chromatic aberration

[Nick Hatton]

Hi there, just had my first quality rejection in over two years and 1500 images, the stated reason is  Chromatic aberration of one image, could do with some help to understand what I am looking for as the shot looks fine to me!

[spacecadet]

Red/yellow or blue/green fringing at the edges of the FoV, particularly high contrast edges- leaves against sky is a classic.

The tick box in LR deals with a lot of it- you can set it as an import preset- and the eyedropper tool in lens corrections will sort out most of the rest.

There's a current thread from geogphotos about it- it's clear on his crop.

[Betty LaRue]

I ran afoul of that a couple of years ago. There was a bit of CA on leaves against a bright sky, far upper left. I just missed it, tucked away in the corner, even looking at 100%. Tired eyes, I guess.

Dont skip the 100% inspection. It reveals bad stuff not seen even at 50%.

I find when I’ve had a failure, it is my fault, not QC.  I’m supposed to be correcting that stuff. QC is just doing a good job maintaining a good product.

Betty

[Matt Ashmore]

18 minutes ago, spacecadet said:

Red/yellow or blue/green fringing at the edges of the FoV, particularly high contrast edges- leaves against sky is a classic.

The tick box in LR deals with a lot of it- you can set it as an import preset- and the eyedropper tool in lens corrections will sort out most of the rest.

There's a current thread from geogphotos about it- it's clear on his crop.

 

Or indeed purple too...

 

https://en.wikipedia.org/wiki/Purple_fringing

 

And another wikipedia link:

 

https://en.wikipedia.org/wiki/Chromatic_aberration

[Nick Hatton]

Thanks all, can see it now but find it very difficult to make out, could be my 60 year old eyes! 

 

[Betty LaRue]

CA and dust spots in the sky were what I needed to watch for the most. Soft, also.  Inspecting more consistently fixed that. If I had to look at a photo for awhile trying to determine if it was sharp enough told me that if I had to look that long, it wasn’t sharp enough. 

I’m sure I binned some that would have passed, but that was when the sin bin time out was 30 days and it wasn’t worth it. Still isn’t at 10 days.

 

Many times I tried to sneak one through against my better judgment, because otherwise,  subject and everything else about it was unique and special. It hurts to toss those.  Some passed, some failed.  Which proved my judgement was faulty.  

Betty

[Nick Hatton]

30 minutes ago, Betty LaRue said:

CA and dust spots in the sky were what I needed to watch for the most. Soft, also.  Inspecting more consistently fixed that. If I had to look at a photo for awhile trying to determine if it was sharp enough told me that if I had to look that long, it wasn’t sharp enough. 

I’m sure I binned some that would have passed, but that was when the sin bin time out was 30 days and it wasn’t worth it. Still isn’t at 10 days.

 

Many times I tried to sneak one through against my better judgment, because otherwise,  subject and everything else about it was unique and special. It hurts to toss those.  Some passed, some failed.  Which proved my judgement was faulty.  

Betty

Thanks Betty, wise words, OK finding dust spots, but this CA!

[John Walker]

The only C.A. I ever have with my Sony RX100 M3 is purple fringing but only in extreme lighting conditions.

 

I don't use Lightroom but have my own way of dealing with it in Adobe Elements that works well for me.  I zoom right in (over 100%)  and go into Adjust Hue/Saturation. I then use the dropper tool to select the purple C.A..  I then reduce saturation which only affects that exact hue. I also find that reducing the brightness turns the C.A. almost black and make that area look sharper.

 

I'm sure there are other methods but I'm comfortable with the method above.

 

John

[famousbelgian]

Virtually all my images are on a white or black background so I have always had to pay special attention in my processing to CA. I find it helps to attack it early on in the process, the only thing I do before ticking the CA box in Adobe Camera Raw (ACR) is colour balance. The CA box will get rid of most of it, sometimes it needs further tinkering with CA sliders. It goes without saying you need to be zoomed in at 100% before ticking the CA box, so you can see what is happening. I then move on to other processing such as vibrance, contrast, highlights, etc.

 

Quality of your lenses is very important to avoid CA. Poor glass = lots of CA, especially superzooms such as 18-200mm or 18-300mm lenses, etc.

Good macro lenses and primes normally have excellent CA resistance.

 

For extreme cases, lowering saturation of the CA area by 30-40% with a small brush can also help.

 

Marc

[Vincent Lowe]

51 minutes ago, famousbelgian said:

Quality of your lenses is very important to avoid CA. Poor glass = lots of CA, especially superzooms such as 18-200mm or 18-300mm lenses, etc.

 

 

 

I have over 11,000 on Alamy taken with a Nikon 18-200.  Never had a QC failure for CA - automatically corrected in Adobe Camera Raw.

[famousbelgian]

46 minutes ago, Vincent Lowe said:

 

I have over 11,000 on Alamy taken with a Nikon 18-200.  Never had a QC failure for CA - automatically corrected in Adobe Camera Raw.

 

Yes, it can easily be removed in ACR as I said. Much of my back catalog was taken with a Canon EF-S 18-200mm, such a poor lens comparing it now against my current lenses, shocking really, but you can't turn the clock back ...

 

I was just making the point that if you want to avoid CA, buy premium glass and try not to use it wide open. 

 

Marc

[Colblimp]

10 hours ago, John Walker said:

The only C.A. I ever have with my Sony RX100 M3 is purple fringing but only in extreme lighting conditions.

 

I don't use Lightroom but have my own way of dealing with it in Adobe Elements that works well for me.  I zoom right in (over 100%)  and go into Adjust Hue/Saturation. I then use the dropper tool to select the purple C.A..  I then reduce saturation which only affects that exact hue. I also find that reducing the brightness turns the C.A. almost black and make that area look sharper.

 

I'm sure there are other methods but I'm comfortable with the method above.

 

John

 

Good one - I'm going to have to steal your idea!

[hdh]

11 hours ago, John Walker said:

The only C.A. I ever have with my Sony RX100 M3 is purple fringing but only in extreme lighting conditions.

 

I don't use Lightroom but have my own way of dealing with it in Adobe Elements that works well for me.  I zoom right in (over 100%)  and go into Adjust Hue/Saturation. I then use the dropper tool to select the purple C.A..  I then reduce saturation which only affects that exact hue. I also find that reducing the brightness turns the C.A. almost black and make that area look sharper.

 

I'm sure there are other methods but I'm comfortable with the method above.

 

John

Also need to try that, my software deals well with CA on straight edges/lines but almost not on CA between leaves. 

This may do the job. 

 

Thanks for the hint & like+1

[MDM]

4 hours ago, hdh said:

Also need to try that, my software deals well with CA on straight edges/lines but almost not on CA between leaves. 

This may do the job. 

 

Thanks for the hint & like+1

The problem here is that you are no longer working on the raw image as it has already been converted so results are much less satisfactory in my experience. It's also very time-consuming. Ticking a box, setting that as a default in LR/ACR and never thinking about it again makes for a far more efficient workflow and, in the case of CA, better results. I do recall you had some problem with using Adobe software. What you are seeing on leaves may not be CA and may not be correctible in this way.

[Inchiquin]

19 hours ago, Nick Hatton said:

Thanks all, can see it now but find it very difficult to make out, could be my 60 year old eyes! 

 

 

After nearly 10 years of poring over 100% views for Alamy submissions, I find I have developed a kind of sixth sense for CA. Even if the fringing is not blindingly obvious there's something just "not quite right" about contrasting edges.

 

Alan

[pablo]

When I started out with Alamy, I had rejections due to CA. Finally upgraded to a Canon EF-S 15/85 lens.  Now use this for 90% + of my image submissions, but correct each one for CA in DPP. Not had a reject since I started doing this.

[Nick Hatton]

18 hours ago, John Walker said:

The only C.A. I ever have with my Sony RX100 M3 is purple fringing but only in extreme lighting conditions.

 

I don't use Lightroom but have my own way of dealing with it in Adobe Elements that works well for me.  I zoom right in (over 100%)  and go into Adjust Hue/Saturation. I then use the dropper tool to select the purple C.A..  I then reduce saturation which only affects that exact hue. I also find that reducing the brightness turns the C.A. almost black and make that area look sharper.

 

I'm sure there are other methods but I'm comfortable with the method above.

 

John my post 

[Nick Hatton]

Just now, Nick Hatton said:

18 hours ago, John Walker said:

The only C.A. I ever have with my Sony RX100 M3 is purple fringing but only in extreme lighting conditions.

 

I don't use Lightroom but have my own way of dealing with it in Adobe Elements that works well for me.  I zoom right in (over 100%)  and go into Adjust Hue/Saturation. I then use the dropper tool to select the purple C.A..  I then reduce saturation which only affects that exact hue. I also find that reducing the brightness turns the C.A. almost black and make that area look sharper.

 

I'm sure there are other methods but I'm comfortable with the method above.

 

John my post 

 

[pablo]

58 minutes ago, geogphotos said:

 

That's very interesting. Does this work in batch mode or do you have to adjust for each image? If for individual images how do you make it easy to identify CA, do you have to open each at 100% and scroll around likely areas.

 

I'm hoping that you will say that you use a fixed setting on the CA slider in Lens Correction and it works for 99% of images  

 

Yes, I use "Lens Correction". This zooms in on image, but can be moved around to show worst CA. Most images I leave setting at 100%, but sometimes have to reduce this as it changes reddish fringe  to green! Only happens infrequently. Haven't found a way of batch processing, so quite time consuming......but still better than rejection

[Number Six]

I always use Capture NX2 for automatic CA removal, even though I changed from Nikon to Fuji X-series some years ago.

 

Basically, I run the 8-bit TIFF outputs from Fuji RAF file processing in Capture One Express 7 (not brilliant for removing CA imo) through Capture NX2's Camera Lens Corrections (with both CA boxes ticked by default). An extra stage in pp, but I also like Capture NX2's horizon tool so I'm prepared to live with a few more button presses.

 

it works for me....