Chromatic abberations

[EchoingWhisper]

Do chromatic abberations matter? Can you fix it in post without reduction in image quality?

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It depends on how bad it is... I think fixing it will pretty much always result in 'some' loss of image quality. That may or may not be noticeable...

Even in B&W, where you wouldn't see it in color, there is still a loss in sharpness.

Whether it matters or not depends on how demanding you are.

[Terenas1986]

Hi, EchoingWhisper!

For example: in Lightroom, you can tell the software what lens you shot the image with... and it will automatically apply (if you select it) all the CA corrections and lens-distortion corrections... and more stuff. Trust me, it's great!

[Alex_B]

CA is somthing which areally annoys me if it is visible. I know some people are crazy for perfect sharpness, others for perfect tonal balance, and with me, it is that I hate CA.

In particular zoom lenses often show a considerable amount of lateral CA, even the good ones. Luckily lateral CA is quite easily reduced if you start from the RAW image, without any loss in image quality. Actually the image in the different colour channels are shifted laterally into the right place, and this increases overall sharpness!

Even when you convert an image with strong CA into black and white, you should also correct CA before the conversion, so the final BW comes out sharper.

It is best done with RAW software which can be calibrated or is calibrated for the lenses you use and recognizes the focal length used. For Canon for example, even the RAW software supplied with the camera does a pretty decent automatic job here if I remember right.

[EchoingWhisper]

CA is somthing which areally annoys me if it is visible. I know some people are crazy for perfect sharpness, others for perfect tonal balance, and with me, it is that I hate CA.

In particular zoom lenses often show a considerable amount of lateral CA, even the good ones. Luckily lateral CA is quite easily reduced if you start from the RAW image, without any loss in image quality. Actually the image in the different colour channels are shifted laterally into the right place, and this increases overall sharpness!

Even when you convert an image with strong CA into black and white, you should also correct CA before the conversion, so the final BW comes out sharper.

It is best done with RAW software which can be calibrated or is calibrated for the lenses you use and recognizes the focal length used. For Canon for example, even the RAW software supplied with the camera does a pretty decent automatic job here if I remember right.

So it doesn't affect image quality? Then Nikon should choose not to correct chromatic abberations at all, saves money, saves sharpness.

[Alex_B]

So it doesn't affect image quality? Then Nikon should choose not to correct chromatic abberations at all, saves money, saves sharpness.

The CA affects image quality in terms of colour fringes and reduced sharpness.

The correction of CA by the use of RAW converters does mean any otherwise loss in image quality, it only improves! That was my statement, as opposed to

I think fixing it will pretty much always result in 'some' loss of image quality. That may or may not be noticeable...

[KmH]

Every lens produces some amount of CA.

How much image quality may be diminished by 'fixing' CA post process depends on the software used, and the skill of the person doing the editing.

Some types of CA cannot be 'fixed' post process.

[Hobbytog]

You should expect some CA in most images. This can be corrected in the full version of Photoshop, i.e. not Elements.

[Like_Breathing]

Shoot in RAW and correct with Adobe Camera RAW. There is virtually no change in IQ, although the nature of correcting CA means the image will shift slightly, maybe by a few pixels.

[Infidel]

Longitudinal, or axial chromatic aberation as it's also known, can not be "fixed" in post production.

[djacobox372]

In my opinion ca actually helps accurately denote contrast. In fact if u look at the work of master painters you will see that they actually incorporate a sort of ca to their high contrast edges to add more realism. This was a practice even before photography existed.

[Garbz]

You should expect some CA in most images. This can be corrected in the full version of Photoshop, i.e. not Elements.

Adobe CameraRAW can correct for CA, so this feature should be available even in Elements.

[sovietdoc]

I heard 5D 3 is the first camera that corrects CA in camera assuming you're using Canon lens. Does anyone know if this is on Jpegs only or in RAW too? I've read that RAW isn't actually corrected in the camera until you use DPP to process the image. Which kind of kills the point...

[Garbz]

JPEG only. All those weird and wonderful settings are JPEG only.

Camera lens corrections (including CA the D800 has those and I thought the D700 did too), "Active-D Lighting", "HDR", any of those image adjustments, sharpening etc. All of this happens in JPEG only.

[KmH]

IIRC, the version of Camera Raw (ACR) in Elements is de-featured. It is my understanding that one of the functions left out is the CA correction function.