First to make one thing clear: crosstalk applies to normal to wide tech lenses (say 60mm and lower) in shifted positions. Table top photography with longer lenses will most likely work extremely well with this camera. But this camera looks like a portable field camera rather than a studio camera, which means that people will be interested in wide angle performance. For studio photography with longer lenses one is probably better off with a camera that has rear movements as well, such as the Rollei X-Act 2 which some users already use with the A7r (it costs twice as much though, $4K).
Back to crosstalk;
Capture One LCC algorithm does not correct crosstalk at all. It's a quite complicated thing to do. However for mild crosstalks you will only get mild color desaturation, so you can ignore it or make a radial saturation increase. For more heavy crosstalk the color will be so dead and/or shifted you cannot just increase saturation, and for severe crosstalk you start to get mazing artifacts in the demosaicing.
Crosstalk with tech cam wides is nothing new. I actually have it even with my large pixel Aptus 75 when combined with the SK35 and shifts, and even with the new SK60XL at the edge of the image circle, so tech cams users have lived with it for long and been satisfied -- mild crosstalk is not too bad, and if the scene does not have very saturated colors you may not even see it. However with the Dalsa 6um sensors (P65+, IQ160) crosstalk became worse and in response SK35 became less popular and many upgraded to the (weak) retrofocus Rodie 32 for better performance with those new sensors.
Then we have IQ180 which have even higher levels of crosstalk, and IQ250 worse than that, and then after that the A7r comes in. So there's a whole new level of crosstalk which we haven't seen before, and thus we haven't really had time to investigate how much post-processing can solve these issues. If we're lucky it can solve a lot.
I just want to warn those that intend to buy into this system early that it may not perform well at all with tech wides, and new post-processing techniques may need to be developed before it will, and it's uncertain at this point how successful that will be.
Back in the days there were many upgrades from P65+ to IQ180 without that the users have been informed about the increase in crosstalk and what effects that would have on the lenses they owned. A7r / Actus is coffee money in comparison of course, but still I hope people get information about this issue this time around, before they buy rather than after.
A simple sanity check test to see if a lens/sensor combination has crosstalk is to shoot one normal white LCC and then one more LCC with a polyester color filter stuck inbetween, say a red Wratten 29 filter so you get a red LCC (other colors work too, but red is best for testing). Then you generate an LCC from the white one and apply to the red shot. If there is no crosstalk you should see a flat red surface with the same saturation over the whole surface. If there is crosstalk you will see desaturation in the red, and if there is heavy crosstalk you may see a color shift, even that red becomes green. Do test both horizontal and vertical orientation of the sensor as the result can differ greatly due to how pixels are wired on the sensor.
The thing with crosstalk is that it will depend on what colors you have in the scene you are shooting what the result will be. If you have colors that are low in saturation the result will be better, as crosstalk will have a lesser effect on those colors. This means that a single scene shot may not give you the whole truth of how the system will perform in various conditions.
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