Adam Maas wrote:
300mm f2.8 (600mm equivalent in 35mm) and 150mm f2.0 (300mm equivalent).
Olympus has taken good advantage of the 2x crop factor.
Not exactly. Compared to APS systems, you can think of the Zuiko 300 F2.8 as
a 600 F4 at best (which is not a bad thing either).
That's because the 2x crop factor of the FourThirds means smaller pixels and
smaller pixels mean at least one (usually around 1.5) lower ISO level for
getting the same result of APS format in terms of noise. So in practice the
2X crop factor eats 1.5 lens stops.
So, with the Oly you have to use a 300 F2.8 at ISO 400 where any APS-format
DLSR can shoot a 400 F4 at ISO 800 (or even 400 F5.6 at ISO 1600).
The same happens at any focal length, hence the 150 F2 on FourThirds is like
a 200 F2.8 on APS (because you have to compensate the noise using a lower
ISO setting and a faster aperture).
Dario
