Sample pictures of the TCON 17 with the Dimage 7i. Unless otherwise stated, photos were taken at full zoom (200 mm) and with the TCON 17 attached. It clearly vignettes, but it is still eminently usable. There is a difference between using at f3.5 and at f9.5 but it's not huge. Shorter focal lengths vignette more. Several pictures were taken with a uv filter (Hoya Super HMC Pro1) in place - which makes little difference. I used a tripod and remote release except for those of the cockerel and the sky which were handheld.
I have just added small crops of the centre and edge of full sized images to allow better comparison of resolution etc.
or 
or 
