Speed Booster Sigma 150-600mm

Started 9 months ago | Discussions thread
rmexpress22 Senior Member • Posts: 1,768
Re: Speed Booster Sigma 150-600mm

Aussie Coop wrote:

Im aware of the new focal length, but how do you come at it being f/7.1 , doesnt the booster increase light by at least 1 stop? So that would make it 682mm f/4.5 at the long end by my calculation ( far from being where it is on the R ). From what Ive read the centre of the image loses very little quality. Im not using a 682mm lens to shoot landscapes so Im really only interested in the centre of the image anyway.

A crop body is like a magic wand. It magically changes the dimensions of your lens and the physical aperture becomes smaller.


An aperture of f/4.5 is the same on full frame, crop, or on a potato. The FOV changes, as you know. The light that passes through the lens is the same.

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