nnowak
•
Veteran Member
•
Posts: 9,076
Re: Speedbooster : Question + an idea
bowserb wrote:
While it might only be a novelty, if Metabones released an EF to EFM speedbooster for their usual $699, I would buy it. A lot of money for a novelty, but I see lenses we already have, for example:
50mm F1.2 acting like a 50mm F0.8. Talk about a low light king!
85mm F1.8 as an 85mm F1.2
100mm F2.8 macro being a 100mm F2.0 macro
35mm F2 is a 35mm F1.4
70-200 F2.8 looking like 70-200 F2.0
14mm F2.8 looking like 14mm F2.0
500mm F4 looking like a 500mm F2.8
In practical terms, it wouldn't mean much, but it sure would be fun! I might switch to nothing but night photography!
Speedboosters don't quite work like that. Aperture increase by one stop and focal length is multiplied by 0.71.
Here is what your lenses become on a Speedbooster
50mm f1.2 becomes 36mm f0.9
85mm f1.2 becomes 60mm f0.9
100mm f2.8 becomes 71mm f2.0
35mm f2.0 becomes 25mm f1.4
70-200mm f2.8 becomes 50-142mm f2.0
14mm f2.8 becomes 10mm f2.0
500mm f4.0 becomes 355mm f2.8
Here is where your theory really falls apart. You are now mounting these lenses on a Canon APS-C crop sensor camera which has a 1.6X crop and is 1-1/3 stops behind full frame. Using the above lenses on a M series camera in combination with a Speedboostes nets you the following full frame equivalents....
50mm f1.2 becomes 57mm f1.4
85mm f1.2 becomes 97mm f1.4
100mm f2.8 becomes 114mm f3.2
35mm f2.0 becomes 40mm f2.2
70-200mm f2.8 becomes 80-227mm f3.2
14mm f2.8 becomes 16mm f3.2
500mm f4.0 becomes 568mm f4.5
While the Speedbooster improves the lenses on a crop sensor, the lenses will still work better natively on a full frame camera.