Canon 1Dx, 500 mm, converter and vignetting

[Jan van Holten]

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.

Thanks,
Jan van Holten

 

[Skulker]

Nice set of shots Jan. Very well taken.

A full fram will tend to show up any vinegetting more simple because its a bigger sensor using more of the image supplied by the lens. Stopping down gets rid of it sometimes, as you have found, or you can revers it in processing.