Teleconverters multiply focal length and f-number by the same factor. A 1.4× costs one stop of light, a 2× costs two — which affects autofocus and shutter speeds.
Enter your lens to see the result.
How it works
Focal × k; aperture × k; light loss = 2·log₂(k) stops.
FAQ
Will autofocus still work?
Many cameras need f/8 or brighter (some f/11) at the effective aperture for reliable AF.
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