  The $\gamma^\ast N \to N(1520)$ transition has a property that differs from
the other low-lying nucleon resonance amplitudes: the magnitude of the
transverse helicity amplitudes.The transition helicity amplitudes are defined
in terms of square-transfer momentum $q^2$, or $Q^2=-q^2$. Near the photon
point ($Q^2=0$) there is a significant difference in the magnitude of the
transverse amplitudes: $A_{3/2}$ is very large and $A_{1/2}$ is very small.
This atypical behavior contrasts with the relation between the amplitudes at
the pseudothreshold [the limit where the nucleon and the $N(1520)$ are both at
rest and $Q^2 <0$], where $A_{3/2} = A_{1/2}/\sqrt{3}$, and also in the
large-$Q^2$ region, where theory and data suggest that $A_{3/2}$ is suppressed
relative to $A_{1/2}$. In the present work, we look for the source of the
suppression of the $A_{1/2}$ amplitude at $Q^2=0$. The result is easy to
understand in first approximation, when we look into the relation between the
transverse amplitudes and the elementary form factors, defined by a
gauge-invariant parametrization of the $\gamma^\ast N \to N(1520)$ transition
current, near $Q^2=0$. There is a partial cancellation between contributions of
two elementary form factors near $Q^2=0$. We conclude, however, that the
correlation between the two elementary form factors at $Q^2=0$ is not
sufficient to explain the transverse amplitude data below $Q^2 = 1$ GeV$^2$.
The description of the dependence of the transverse amplitudes on $Q^2$
requires the determination of the scale of variation of the elementary form
factors in the range $Q^2=0$...0.5 GeV$^2$,a region with almost non existent
data. We conclude at the end that the low-$Q^2$ data for the transverse
amplitudes can be well described when we relate the scale of variation of the
elementary form factors with the nucleon dipole form factor.
