Canon 1D MkIV purple fringing - PLEASE HELP!!

Lens not body !!

phreeky wrote in post #10880902
That is horrible CA. But I've seen other complaints of the CA from the 85 F/1.2 so I'm not overly surprised.

F/2 or so wouldn't have ruined those shots.

They're not ruined. a) some of the fringing can be fixed in post. Since there is no purple in the actual picture, turn down purple saturation and you're halfway there. For some shots where I've caught a subject against a white background, you'd be surprised how happy a customer is with a well converted black and white image

I mean 1.2 is more than two full stops faster than 2.8. There are just going to be some problems at 1.2. Its just physics and unless Canon was to ad a fluorite element and then the lens would even cost more than it does now, theres going to be some CA at 1.2. In most shooting situations that require you to shoot wide open its really not much of a problem and in those dark situations when 1.2 is the only option you ain't gonna get the shot with the zoom.

One of the only really fast lenses that I know of that doesn't show CA is the 200 2L. I mean Canon could make an 85 1.2 lens that would almost be CA free but would you spend 4K + on it?

haha no no TaDa I gotcha

Ok so basically... Solution = Don't shoot such high-contrast situations with 85mm when wide-open or at least close it down to 2.0 or so to avoid CA?

TaDa wrote in post #10880924
They're not ruined.

I wasn't implying they were! What I meant was that stopping down a bit would've reduced the CA, and the smaller aperture wouldn't have greatly taken away from the images.

airfrogusmc wrote in post #10880943
I mean 1.2 is more than two full stops faster than 2.8. There are just going to be some problems at 1.2. Its just physics and unless Canon was to ad a fluorite element and then the lens would even cost more than it does now. In most shooting situation that require you to shoot wide open its really now much of a problem and in those dark situations when 1.2 is the only option you ain't gonna get the shot with the zoom.

One of the only really fast lenses that I know of that doesn't show CA is the 200 2L. I mean Canon could make an 85 1.2 lens that would almost be CA free but would you spend 4K + on it?

That too. For the amount of fluorite that they'd have to use to control all aberration on a 1.2 lens, the 85L would be pretty much made of 10 fluorite elements and cost a little less than a new car.

tinycomet wrote in post #10880951
haha no no TaDa I gotcha

Ok so basically... Solution = Don't shoot such high-contrast situations with 85mm when wide-open or at least close it down to 2.0 or so to avoid CA?

ding, ding, ding...give the man a ceegar!

TaDa wrote in post #10880967
ding, ding, ding...give the man a ceegar!

Cuban please :P

By the way, it hasn't been said yet, but I like the captures. You had a great couple to work with. Good to see that they were good sports. Don't know if biting your wife's head like an apple is 11x14 material, but they look like they had a blast . Good job letting them be themselves.

fusionphoto wrote in post #10880916
Lens not body !!

CA is

whereas purple fringing is

in the sensor. One is a lens issue; the other is a body/sensor issue.

Quotes from dp review.com - Chromatic Aberration

@TaDa thanks I do my best to get myself in a position where they are no longer aware of my presence

@RTPVid, are you suggesting a body/sensor problem?

It's not the body, it's the 85L....If it's the 85L (version 1) it's even more noticable...Anything under f2 will have a tough time in those situations.

tinycomet wrote in post #10882362
...@RTPVid, are you suggesting a body/sensor problem?

More like a sensor characteristic or limitation. The sensor has millions of tiny lenses (microlenses) covering the sensor elements (pixels). These microlenses are subject to the same optical issues as any other lens, including chromatic aberration. The "white" areas of your pictures are overexposed and have exceeded the dynamic range of the sensor. This can result in "blooming" (spilling over of charge to neighboring sensor elements) which tends to increase the effect of microlens CA. If this is what you are seeing, the purple fringing would be present with similar subjects shot with similar over-saturation of the sensor regardless of the lens. However, it would need to be a "fast" lens to get the same over-saturation effect, hence you are more likely to see this with your 1.2 lens shot wide open than with that same lens stopped down (or with other slower lenses). But, if you can create the same effect with the slower lens and a slower shutter speed, then it is a sensor "feature".

Sensor designers build anti-blooming into the electronics, but even this can be overwhelmed with extreme overexposed areas with high contrast.

CA from your lens will tend to be toward the edges of the frame and can be in cyan, red, etc., whereas CA from the sensor microlenses will be purple and occur throughout the frame.

You could try film for your high key shots! Or, fix it in post-processing.

it's the lens... Interesting you never saw the fringing on the 1Diii or did you not have the 85L then?

here's an example of my own:

I agree, the 85L wide open in high contrast situations has that.