What are you trying to DO here? Turn a 10mm lens into a 15mm lens, expanding the center of the image circle to cover the FF sensor so you don't get that dark vignette? I guess that must be it.
Here's my gut feeling: you have a very nice sensor, just CROP. You'll get the exact same effect without introducing the variable of an inexpensive, less finely-engineered optical component into the image path. The 6D sensor, cropped to APS-C dimensions, is STILL better IQ than, say the 20D that was state of the art when I got it.
I have NO problem doing extreme crops on the 5D2, for what it's worth. |
