With the arrivel of a confinding juvenile Bairds Sandpiper on the Dutch coast and the first serious photography with my 1Dx, I discovered a complete new phenomenon for myself. The 1Dx is my first fullframe camera. I took my pictures with a ( type 1) 500mm/F4 and with a 1.4x converter ( type2 ) attached. With an aperture set on 5.6 there is obvious vignetting noticable. It disappears pretty much when the aperture is set to 7.1. So far I only knew of vignetting with wide-angle lenses. Compared to my mark 4, I have to trust the much better image quality at iso's above 500.
Is that a phenomenon occuring only with the older 500 mm, or is it due to the use of the converter? Does it also appears with the new telelenses?
By the way, the bird was not getting an very nice welcome. It was sand-blasted a lot on our sandy beaches.
Jan van Holten