brianc1959 wrote:rick.lang wrote:Jason Bourke-Velji wrote:17.5mm Voigtlander f0.95 or Nikkor AIs 50mm f1.2 w/ speedbooster
I think the Metabones Speed Booster requires a minimum f/1.4 lens which would take you to f/1.0. Starting with f/1.2 won't function properly.
Rick Lang
Sent from my iPad using Tapatalk HD
Hi Rick:
The Metabones Speed Booster is fully compatible with f/1.2 lenses. However, "f/1.2" is actually f/(cuberoot(2)) = f/1.2599 ~f/1.26. So what you get is f/(1.26 x 0.71) = f/0.90 .
Brian
Thanks, Brian. You are correct. I think when the white paper came out ages ago, they mentioned the f/1.4 limit, but obviously with the actual product released, it does work with faster lenses. From Metabones website:
"Petersburg, VA, USA, January 14, 2013 - Metabones[REGISTERED SIGN] and Caldwell Photographic jointly announce a revolutionary accessory called Speed Booster[TRADE MARK SIGN], which mounts between a mirrorless camera and a SLR lens. It increases maximum aperture by 1 stop (hence its name), increases MTF and has a focal length multiplier of 0.71x. For example, the Canon EF 85mm f/1.2L II lens becomes a 59mm f/0.9 lens on a Sony NEX camera, with increased sharpness."
Rick Lang
Sent from my iPad using Tapatalk HD