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Still loving the M6II, even more with new DXO

Started 3 months ago | Discussions thread
nnowak Veteran Member • Posts: 9,075
Re: DxO PL6 Comparison Deep Prime vs XD; Classic color vs wide gamut

m100 wrote:

Larry Rexley wrote:

Rokinon 135mm f2.0 with Viltrox 0.71x speed booster making it a 100mm f1.4 lens).

I am trying to figure this stuff out.

135 x 1.6 = 216

216 x .71 = 153.36

So on the M6II instead of looking like a 216mm lens on a FF your 135mm lens with a .71 speed booster would look like a 153mm FF lens on a cropped Canon sensor ?

https://www.metabones.com/article/of/faq

Not quite.

A 135mm f/2.0 lens on a 0.71X speedbooster becomes a 96mm f/1.4 lens.

A 135mm f/2.0 lens on Canon crop has a full frame equivalence of 216mm f/3.2

A 96mm f/1.4 lens on Canon crop has a full frame equivalence of 153mm f/2.2

The basic premise of a speedbooster is to make a full frame lens on crop produce an image roughly equivalent to the bare lens on full frame. In practice it does not quite work out that way.

Whenever you are looking at using a speedbooster, it is simpler to just think in terms of the new, speedboosted lens as a single unit. In this case, that would be a 96mm f/1.4 lens.

To confuse things further, a speedbooster is just the exact opposite of a 1.4X teleconverter.

A 135mm f/2.0 lens on Canon crop has a full frame equivalence of 216mm f/3.2

A 135mm f/2.0 lens on a 1.4X teleconverter on full frame becomes a 189mm f/2.8

All of these numbers get closer to each other when you are using a 1.5X crop sensor like Sony or Fuji instead of a 1.6X crop sensor from Canon.

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