Alpha_Geist wrote:
I have a few question regarding the Oly m4/3 sensor and the Metabones Speed Booster adapter.
Has anyone used it on their Oly? If so, how is the f/no. affected with the speed booster on the m4/3 sensor? I know the speed booster improves light gathering/speed by 1 stop, and the focal length is widened by 1.42x (.71 for the adapter and 2x for the m4/3 FF equivalent focal length = 1.42x), but the f/no. is still faster.
- Example -
50mm f/2 lens Speed Boosted on a m4/3 camera becomes:
FOCAL LENGTH maths
50mm x .71 = 35.5mm x2 (for FF equivalent focal lengths on m4/3 sensor) = 71mm
F/no. maths
f/2 -> 1.4 from speed booster, but then becomes a f/x for FF equivalent?
I\'m getting a bit tripped up with FF equivalent conversions with m4/3 sensors and throwing in a Speed Booster only added to it.
I\'ve been looking at the Oly and Fuji offerings and have been swayed by the IBIS of the Oly.
The focal length will become .71x. The physical aperture will stay the same size. Since we think of aperture in porportion to focal length, and F changes, the demoninator in our F stop will change by .71x.
Of course, when comparing to another format, we also have to consider aperture equivilence.
So for example, my Rokinon 85mm F/1.4 on the speedbooster becomes a 60mm. The physical aperture also happens to be 60mm (85mm/1.4 = 60mm). Since that did not change, but the focal length does, the maximum F-stop is reduced to 1 -- (60mm(new focal length)/x = 60mm(aperture size), solve for x).
To compare to a different format, we use crop factor to account for focal length and depth of field equivilence. Mounted on the OM-D, this speedboosted Rokinon at 60mm F/1 gives an equivilent shooting experience (depth of field and angle of view) to a 120mm F/2 on full frame.
Alpha_Geist wrote:
I have a few question regarding the Oly m4/3 sensor and the Metabones Speed Booster adapter.
Has anyone used it on their Oly? If so, how is the f/no. affected with the speed booster on the m4/3 sensor? I know the speed booster improves light gathering/speed by 1 stop, and the focal length is widened by 1.42x (.71 for the adapter and 2x for the m4/3 FF equivalent focal length = 1.42x), but the f/no. is still faster.
- Example -
50mm f/2 lens Speed Boosted on a m4/3 camera becomes:
FOCAL LENGTH maths
50mm x .71 = 35.5mm x2 (for FF equivalent focal lengths on m4/3 sensor) = 71mm
F/no. maths
f/2 -> 1.4 from speed booster, but then becomes a f/x for FF equivalent?
I\'m getting a bit tripped up with FF equivalent conversions with m4/3 sensors and throwing in a Speed Booster only added to it.
I\'ve been looking at the Oly and Fuji offerings and have been swayed by the IBIS of the Oly.
The aperture will become .71x, as the focal length will. Of course, when comparing to another format, we have to consider aperture equivilence.
So for example, my Rokinon 85mm F/1.4 on the speedbooster becomes a 60mm F/1. Mounted on the OM-D, this gives an equivilent shooting experience (depth of field and angle of view) to a 120mm F/2 on full frame.
Mar 20, 2014 at 10:25 AM
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