Dear "mjon",
Just to clarify my position: I did not mean to say that one does not need to perform a "white shading" with a P45, I would even recommend to do so with any digital back and
even with longer FL lenses: a sensor never has a linear response all over its surface, as shown here.
In addition to this, I also need to say that your colour cast showed here (due to the
non-linear response of the sensor) has nothing to do with the type of colour cast produced by short FL lenses (non-retrofocus) on sensors with micro-lenses
or with larger sensors like the ones used in the IQ DBs (due to
the strong angle at which the light hits the pixels).
Important remark: the non-linear sensor response can be corrected to a certain extend in factory (internal factor), the effect of the light incidence on the pixel cannot (external factor).
Best regards
Thierry
I have to say that I am a bit baffled: While you get less color cast using a P45+ in comparison to a P40+, I'd say there is no way to use the P45 with wide angle lenses without LCCs. When I had to make up my mind which way to go, I compared the P45+, the Aptus 8 and the P40+. Color cast with the P45+ was worse than expected and not acceptable. So I'd say it's of little help that it is less severe than using a P40+: You still need LCCs.
The attached LCC shot (yes, the sensor was incredibly dirty) is from a test of the P45+ with, if I remember correctly, the HR-Digaron W 40mm.