Yes, because the f number is a ratio between the effective aperture vs the length of the lens. A long lens with larger f number can focus more light into the se

Yes, because the f number is a ratio between the effective aperture vs the length of the lens. A long lens with larger f number can focus more light into the sensor than a shorter one with a smaller number, say f/4.0 400mm against a f/2.0 50mm.