400mm 5.6 CA ?

Was doing some shooting with my 400 5.6 on Saturday and I noticed some pretty annoying CA on a few shots. It's mainly noticeable in water droplets that are exposed to the sun or on wet spots that are bright, basically overexposed areas. Sorry I don't have any pics, I deleted the card already and forgot to save those shots.

I did work on them in DPP before I deleted them and was able to get rid of most all of the purple dots by applying "Color Blur" correction.

Is this common to see with this lens ? I've done alot of shooting around water with the 100-400 and never noticed this at all.

I have never noticed this myself. An example would really help. I suppose some CA wide open is to be expected. Few lenses are without it.

I had a 300 f4 non IS that had the same CA as this 400. I could not correct that one in DPP because the lens isn't supported for lens corrections. Below is a picture that I took with the 300, this is the exact same type of color blur that I got with the 400 the other day.

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If you can reproduce that CA on a static target then it might be worth trying a little micro-adjustment in your camera. The focus accuracy can affect how badly purple CA shows up in the final image. (see here).

In general I've found the 400L to be very resistant to CA except in extreme circumstances.

Diver-Down wrote in post #8434355
I had a 300 f4 non IS that had the same CA as this 400. I could not correct that one in DPP because the lens isn't supported for lens corrections. Below is a picture that I took with the 300, this is the exact same type of color blur that I got with the 400 the other day.

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That's PF (Purple Fringing) actually. The difference with true CA is that this always surrounds areas of very high contrast, like water drops in bright sunlight against a darker background. CA you'll normally only see at one side of the contrast edges, rather than surrounding it.

PF is one of the most difficult problems to solve in processing, for the simple reason that it is probably a mix of optical aberrations and sensor blooming, i.e., (extreme) overexposure on the sensor leading to an effect on nearby pixels, causing these fringes and therewith loss of information.

AFAIK, only DxO Optics is capable of solving these problems, partly, after the fact. Maybe the newest versions of DPP can deal with this a little too, I don't know. Before the fact you can try underexposing a little in these circumstances, or use a polarizer, which will help to some degree too. Oh, and don't shoot wide open in those circumstances, stop down at least 1 or 2 stops. It gets a lot less when stopping down because it also seems related to some optical aberrations.

Kind regards, Wim

Thanks for the input ! I'll have to try stopping down on my still shots next time out to see if that helps.