Andrew Gough wrote:
Samuli,
I had a lot of problems with a non name adapter and the 180mm F/2.8 APO. In the end, I bit the bullet for a Rayqual, and its bang on. What camera are you shooting?
The metabones seems to be ok with wides, but I am getting quite a bit of vignetting on the longer tele's and zooms.
Andrew
It's understandable to have issues with large exit pupil lenses. In dpreview review they said even EF85/1.8 caused vignetting. Aperture in 85mm f/1.8 lens is 85mm/1.8=47,2mm, so no wonder 180mm f/2.8 causes issues (64,3mm aperture). For wide angle lenses it should cause no issues since for example 35mm f/1.4 lens has aperture of 25mm. Naturally things are not as simple as it may seem based on above since the exit pupil size + angle of rays coming from end of the lens is not determined only by aperture of the lens.
I think that the small lens mount puts limitations for these large aperture lenses with this kind of "reverse teleconverter", or should we call it "wideconverter". Good thing is that one can focus wide open even there is some vignetting.
I'm currently shooting with 5DmkII bodies, so I don't need this kind of adapter, but technologically very interesting component.
Samuli