  To probe manifestations of multiband superconductivity in oxypnictides, we
measured the angular dependence of magnetic torque $\tau(\theta)$ in the mixed
state of SmO$_{0.8}$F$_{0.2}$FeAs single crystals as functions of temperature
$T$ and high magnetic field $H$ up to 30 T. We show that the effective mass
anisotropy parameter $\gamma$ extracted from $\tau(\theta)$, can be greatly
overestimated if the strong paramagnetism of Sm or Fe ions is not properly
taken into account. The correctly extracted $\gamma$ depends on both $T$ and
$H$, saturating at $\gamma \simeq 9$ at lower temperatures. Neither the London
penetration depth nor the superfluid density is affected by high fields fields
up to the upper critical field. Our results indicate two strongly-coupled
superconducting gaps of nearly equal magnitudes.
