@interact
def _(f_main_ = slider(range(5, 100), label='Main Lens Focal Length'),
f_mla_ = slider(srange(0.02, 0.05, 0.001), label='Microlens Focal Length')):
lr(z) = lamb_range.subs({f_main: f_main_, f_mla: f_mla_})
pt = plot(lr, 100, 1000, axes_labels=["Subject Distance (mm)", "Lambda Range"])
html('$f(x)\;=\;%s$'%latex(lamb_range))
show(pt)