Great, thanks for your thoughts Alex. All seems very plausible to me. The images I posted were all from my new Samyang at either f1.4 or f1.8. I think I took a couple at f2 as well so I'll do more of a comparison tonight. I also did a shoot with various lenses in better conditions last night so will post those as well to see if it still shows up.
With the better quality ISO on these new cameras (inc. 5DIII) it's much more possible to stop lenses down and still obtain great low light images now. For every criteria that I look at, these cameras have such great direct and flow-on improvements, such as this example.
Quote:
Originally Posted by alexch
I'd guess it is a combination of a lens, f/stop and the microlenses in front of the digital sensels. These microlenses are designed to collect the light falling onto the sensels at steeper angles and, in doing so more efficiently, they also introduce more chromatic aberrations.
If you stop the lens down then the light falls more perpendicularly to the imaging plane and the problem should disappear.
Some lenses, especially ultra-wides from the film era, are worse than others and produce steeper cones of light. I would not conclude that it is the sensor fault because have not seen any purple fringing when using Nikon or Sony with my reasonably fast f/3.6 reflector. More pronounced fringing with Nikon or Sony when compared to Canon could be because the microlenses on Nikons are more efficient in collecting that steep light cone or that the microlenses themselves introduce some CA.
Just my thoughts.
Alex
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