Removing color casts... the easy way?

A while back I recall either reading or hearing about a magenta to green shift in phase one backs. The following is from an article written on the luminous-landscape by Nick Raines:

"One design problem with extreme wide angles on digital sensors is a colour shift at acute incidence angles. This lens shows a distinct magenta to green shift from the centre to the edge which exaggerates the falloff. Fortunately the Phase One Capture One Pro 3.7.3 software includes a facility for calibrating this hue shift, for each lens and at any movement setting. You simply cover the lens with the white perspex calibration panel and shoot a frame. Import this into CO and under the Colour Balance tab there is an option to Colour Calibrate the lens. You need to do this for different light sources and for each lens, but the software corrects for colour shifts and a bit of falloff. It works well in practice and is a snap to actually do."

I've seen this process in action and thought it was pretty neat. Recently it got me thinking is there a possibility that one could use this white perspex calibration panel when photographing a scene with mixed lighting and have it neutralize color casts?

Jeremy Jachym said:

Recently it got me thinking is there a possibility that one could use this white perspex calibration panel when photographing a scene with mixed lighting and have it neutralize color casts?

Click to expand...

Depending on the exact implementation in software, yes, although it won't offer anything better than an average color temperature over the field of view (so subject colors will influence the result). You would have to use it (similar to an 'Expodisc', but a lot cheaper) by shooting the incident light falling on the scene (like an incident light meter). Depending on the scene, you may get better results from multiple white balanced Raw conversions of the same file, blended in postprocessing.

Bart

Bart, thanks for your reply.

As a result of what you wrote I began to explore what the Expodisc is and it's like what you wrote: "like an incident light meter". I already use a whibal card for color, so I'm not in too much of a hurry to invest in another product that does about the same thing.

On the other hand, while investigating reviews of the expodisc I discovered incamera: http://www.pictocolor.com/incamera.htm . This camera profiling device has perked my interest. I shoot on location, so I would have to set up a color checker for each scene, but I can rationalize the effort involved. What I would like to know is if there is a way to tag a RAW file with the ICC profile created by incamera.

I've posed this question to someone with considerable digital photography knowledge and their response was: "How could that be? Raw does not have really any meaningful colors before debayering." But if that response is accurate than how does one explain Capture One's ability to assign icc profiles? So, maybe I'm answering my own question, but is this also a possibility with Lightroom or DPP? It seems like Capture One and RAW Developer might be the only RC's I use where this is a possibility...? I'd appreciate some clarity around this subject. Thank you.

JJ